2016 @dentallib Aarti Daswani Short Textbook of Endodontics
2016 @dentallib Aarti Daswani Short Textbook of Endodontics
2016 @dentallib Aarti Daswani Short Textbook of Endodontics
Foreword
Sharad Kokate
Short Textbook of
Endodontics
Short Textbook of
Endodontics
Foreword
Sharad Kokate
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ISBN 978-93-5250-121-2
Printed at
Dedicated to
My Parents
(Mr Rupchand and Mrs Sangita Daswani)
Foreword
It is a proud moment and a great pleasure to see one of our talented graduates writing the Short Textbook
of Endodontics.
Aarti Daswani’s strong will and passion for last several years after graduation has given a wonderful
shape to the final content of this textbook. Aarti Daswani has made an excellent attempt at making the
indispensable knowledge of Endodontics easier to understand for the students as well as clinicians. The
unique feature of this textbook is the mind-maps in each chapter, which should help in summarizing and
memorizing during examinations.
The meticulously prepared content will further help as an invaluable reference for the students as well
as clinicians. The language of the textbook is very simple and the diagrammatic representation makes it
simpler.
I am confident that the book will go a long way in clearly simplifying and developing interest amongst the readers.
Sharad Kokate
Dean, Professor of Conservative Dentistry and Endodontics
Yerala Medical Trust’s Dental College and Hospital,
Kharghar, Navi Mumbai, Maharashtra, India
Vice President
Maharashtra State Dental Council
Mumbai, Maharashtra, India
Preface
What led me to the idea of writing Short Textbook of Endodontics is an astonishing realization that the field of Endodontics has
undergone sea changes in the last few years. Endodontic treatment has come a long way from what it was till about two decades
ago. Not only dental materials and instruments have become technically superior, but also the concepts, procedures and attitudes of
clinicians have acquired a modern outlook. Technology has made Endodontic treatment swift, convenient, easier and interesting.
In addition to incorporating the new developments in Endodontics, Short Textbook of Endodontics has been designed to
cover each and every aspect of Endodontics in a concise yet comprehensive manner. Considering the fact that time is a critical
factor in today’s competitive and busy world, there is no doubt that reading big fat textbooks to get through the examinations
is an uphill task for the students. However, remembering the information is important and this requires repeated reading and
revision. This book is expected to make reading Endodontics interesting and a fun-filled experience through the use of different
memory improvement techniques. Purpose of this book is not to serve as replacement of standard textbook but to complement
the textbook and be used solely for revision.
Thus, Short Textbook of Endodontics is a:
• Memory aid: That helps you memorize, retain and reproduce the required information of the basic texts.
• Rapid revision guide: That helps you save time and quickly revise the subject while preparing for the examinations.
Unique feature of this book is inculcating learning through “Mind-maps”, a concept introduced by Tony Buzan, popular
Psychology author and television personality. A mind-map is a diagram used to visually organize information. This diagramming
tool can be used to generate, visualize, structure and classify ideas and as an aid to studying and organizing information in a
concise yet comprehensive manner. Mind-maps used in this book act as a quick learning aid to the ever-expanding world of
Endodontics. Of course, it goes without saying that mind-maps are just meant to help the reader remember all relevant points
of a topic and should not be reproduced in the examination papers as the same may not be acceptable.
The general practitioners can use this book to train their mind to remember what next in the course of performing Endodontic
procedures. The book will serve as a foundation for sound theoretical knowledge, based on which practitioners can perform
better in a given clinical situation.
Writing this book would not have been possible without contributions from multitude of people including my college teachers,
eminent Endodontists and general dentists, computer experts and artists.
“If you cannot explain it simply, you do not understand it well enough”—Albert Einstein.
Through this book, I have made a sincere attempt to simplify the subject of Endodontics based on my understanding and
clinical experience of seven years. I hope it will be useful to the readers.
I look forward to your suggestions, contributions and comments on Short Textbook of Endodontics (First edition) for future
additions and improvements.
Aarti Daswani
Acknowledgments
First and foremost, I would like to express my heartfelt gratitude to my Satguru and God Almighty for all their blessings,
unconditional love and wealth of knowledge they have showered on me and continue to shower on me every single day.
My sincere thanks to my parents for being a constant source of support and encouragement in all my endeavors and for all
their love and sacrifices. Special thanks to my younger sister Yogi, for introducing me to Tony Buzan’s concept of ‘Mind-maps’ and
to my elder sister Lata, for being my critic, inspiration and guide throughout the compilation of Short Textbook of Endodontics.
Special thanks to my dear friends Mamta, Samta, Jayshree, Amita and Kanika for their constant motivation and encouragement
that inspired me to move faster towards realizing my dream of being an author.
I am grateful to my assistants in clinical practice, Maya and Kalpana, for their support and cooperation during the compilation
of the book.
I would like to thank Shri Jitendar P Vij (Group Chairman), Mr Ankit Vij (Group President), Mr Tarun Duneja (Director–
Publishing), Mr KK Raman (Production Manager) and the entire team of M/s Jaypee Brothers Medical Publishers (P) Ltd, New
Delhi, India, for believing in my convictions and giving me an opportunity to write this book and allowing me to make a small
contribution to dental profession in my own way. Special thanks to Mr Ramesh Krishnamchari and Mr Sabarish Menon (Author
Coordinators), Mr Sunil Dogra (Production Executive) and Mr Mohit Bhargava (Production Coordinator), of M/s Jaypee Brothers,
for guiding me throughout the project.
My heartfelt thanks to Dr Sharad Kokate, Dean, Yerala Medical Trust’s (YMT) Dental College and Hospital, Kharghar, Navi
Mumbai, for giving me permission to use innumerable reference books from college library and for his constant support, guidance
and encouragement throughout the compilation of the book. He also very kindly agreed to write the foreword for the book.
I am truly indebted to my teacher Dr Mrunalini Vaidya, who is a great Endodontist, an excellent academician and a Professor
at YMT Dental College and Research Institute, Navi Mumbai, Maharashtra, India, for Conservative Dentistry and Endodontics.
I take this opportunity to extend my deep gratitude to her for devotion of her time and dedicated efforts in critically evaluating
each chapter and providing valuable suggestions to improve the book.
My sincere thanks to Dr Vishal Rathod for creating amazing diagrams and simplified illustrations for the book.
I am grateful to Dr Manoj Ramugade, MDS, Conservative Dentistry and Endodontics, teacher at Nair Hospital Dental
College, Mumbai, Maharashtra, India, for his valuable contribution towards the layout of the book. He also helped me with critical
evaluation of initial chapters and gave valuable suggestions to improve the contents including contribution by way of some very
good photographs and radiographs for the book.
I am thankful to my friend Dr Suvarna Kondawale for going through the chapters and providing suggestions for improvement.
Many thanks to Dr CR Suvarna for providing few photographs of Endodontic equipment and also his case photographs.
I am really grateful to Dr Ajay Bajaj for his critical evaluation and valuable suggestions as well as encouragement and support
including contribution in the form of his case radiographs for the book.
Many thanks to Dr Ashwin Jawdekar for providing useful information, case radiographs and photographs for the three
chapters namely Pediatric Endodontics, Pulp Therapies and Management of Dental Traumatic Injuries.
My heartfelt thanks to Dr Mansi Shah for contributing valuable information on Cone Beam Computed Tomography (CBCT)
scans in the chapter Diagnosis and Diagnostic Aids in Endodontics and for providing her case radiographs and CBCT scans for
the book.
xii Short Textbook of Endodontics
My deep appreciation to Dr Shivani Bhatt, a dynamic and enthusiastic dentist for contributing her case photographs and
radiographs for the book.
My humble gratitude to Dr Roheet Khatavkar, an Endodontist par excellence, who uses all the latest available equipment and
instruments in Endodontics selectively for his cases, for contributing valuable information and his case radiographs.
I am grateful to Dr Nilesh Kadam for contributing his case radiographs for the book.
I am thankful to Dr VS Mohan, Dr Mukul Dabholkar, Dr Rajesh Podar, Dr Raunak Rai, Dr Paresh Dodhiwala, Dr Samir
Khaire, Dr Rajesh Shivhare, Dr Ritesh Mahashabde, Dr Sonam Singh, Dr Mugdha Mitkar, Dr Nomal Sheth and Dr Dharna Parekh
for their contribution, help and support for the book.
I am grateful to Dr Chetan Shah for his sincere and enthusiastic support and encouragement, which helped me give a new
dimension to the book.
My special thanks to Dr Cliffton Ruddle for giving me permission to use photographs from his inventions in Endodontics.
Also special thanks to American Association of Endodontists for giving me permission to reprint the Endodontic case difficulty
forms.
Heartfelt thanks to Dr Priyanka Karande and Dentsply company for providing me with high resolution photographs of
Dentsply Endodontic products; to Mr Amit Borkar and Dr Raghu for providing me with high resolution images of the Sybron
Endo products; to Mr Guru and Micro-Mega company for providing me with high resolution images of the Micro-Mega Rotary
Endodontic system; to Re Dent Nova company and Dr Ajit Jha for valuable information and photographs of the latest self-adjusting
file system.
My sincere gratitude to Mr A Sawant for preparing the initial computerized typescripts of the entire textbook.
Contents
1. Introduction 1
What is the Scope of Endodontics? 1; What are the Aims and Objects of Endodontics? 2;
What are the Changes and Recent Advances that have Occurred in the Field of Endodontics? 2
6. Endodontic Microbiology 83
What is the Basis of Focal Infection Theory and why is it Totally Rejected Today? 83; What are the Pathways
or Portals of Entry of Microorganisms in the Pulp? 84; What is the Microbial Flora of Root Canal? 84;
Which are the Types of Endodontic Infections? 86; What is the Role of Microbial Virulence and Host Response
in the Pathogenesis of Disease? 88; What are the Methods for Detection, Identification and Examination of
Microbes from a Root Canal? 89; What is the Biofilm and What is its Significance in Endodontics? 92
to Determine them? 233; What are the Current Concepts and Terminology for Root Canal
Preparation? 241; What are the Different Instrument Motions for Effective Shaping of Root Canals? 243;
What are the Requirements before Starting Canal Preparation? 244; Which are the Different Root
Canal Preparation Techniques? 244; What are the Precautions to be taken during Instrumentation? 262;
What are the Procedural Errors that can Occur during Root Canal Preparation? 263
Selection? 365; What are the Required Physical Characteristics of the Core? 367; What are the Different
Types of Core Materials? 367; What is the Technique of Fabrication of Foundation Restoration? 369;
What are the Causes of Failure of Post and Core Restorations? 372
Index 507
1
CHAPTER
Introduction
This chapter gives an overview of the subject of Endodontics and its importance in the field of dentistry.
You must know
• What is the Scope of Endodontics?
• What are the Aims and Objects of Endodontics?
• What are the Changes and Recent Advances that have Occurred in the Field of Endodontics?
WHAT ARE THE AIMS AND OBJECTS OF The aims and objects of Endodontics can be summarized
as given in Figure 1.2.
ENDODONTICS?
(Remember the mnemonic: P3 R3 ESS).
Schilder stated goals of Endodontics: “Root canal systems
must be cleaned and shaped to receive a three-dimensional WHAT ARE THE CHANGES AND RECENT
hermetic (fluid-tight seal) filling of the entire root canal
ADVANCES THAT HAVE OCCURRED IN
space.”
“The logical goal of Endodontic treatment is to eliminate
THE FIELD OF ENDODONTICS?
or substantially reduce the microbial population within the In the last 2–3 decades, lot of advances have taken place
root canal system and to prevent reinfection by a tight seal in the art of Endodontics and science of Endodontology.
of the root canal space.” (PNR Nair, Pathways of Pulp, 9th Epidemiological studies suggest that the percentage of teeth
edn. p.573). that can be retained through contemporary Endodontic
Introduction 3
therapy is rising well above 90%. Millions of teeth are being to be achieved remain same but ‘How’ these goals can
saved and then successfully restored to their full functional be achieved efficiently, effectively and without much
and esthetic value. discomfort to the patient in as less time as possible, has led
to a lot of research in this field. Few examples of change
Sea changes in Endodontics: There have been major in Endodontics are listed in Table 1.1. These have been
changes in the practice of Endodontics. Although goals explained in detail in the respective chapters.
4 Short Textbook of Endodontics
This chapter describes the anatomy, embryology, histology and the physiology of the human dental
pulp and its surrounding periradicular structures.
You must know
• What is the Dental Pulp and the Dentin-Pulp Complex?
• What are the Special Characteristics of the Dental Pulp as Connective Tissue?
• How is the Dental Pulp Formed?
• What are the Histologic Features of the Dental Pulp?
• What is the Blood Supply of the Pulpal Tissues?
• What is the Nerve Supply of the Pulpal Tissues?
• What is the Lymph Supply of the Pulpal Tissues?
• What are the Functions of the Dental Pulp?
• What is the Morphology and Histology of the Periradicular Tissues?
WHAT IS THE DENTAL PULP AND cusps of each crown are called pulp horns. The pulp organ
THE DENTIN-PULP COMPLEX? constricts in the cervical region of the tooth and at this zone,
the coronal pulp joins the radicular pulp.
Dental Pulp
Radicular pulp extends from cervical region of crown
Dental Pulp is a soft vascular connective tissue of mesen to the root apex. Radicular portion of the pulp organ
chymal origin occupying the pulp chamber and the root communicates with periapical connective tissues through
canals and provides dentinogenic, nutritive, sensory and the apical foramen or foramina.
defensive functions reflecting complete tooth vitality. The anatomic components of the pulp cavity are
A total of 52 pulp organs are usually present in human discussed in detail in Chapter 3: “Morphology and Internal
dentition, 32 in the permanent teeth and 20 in the primary Anatomy of the Root Canal System”.
teeth. Each pulp organ has the shape that conforms to that
of the respective tooth. Dentin-Pulp Complex
Each pulp organ is composed of:
• Coronal pulp: Located centrally in the crowns of the The specialized cells of the dental pulp, the odontoblasts,
teeth. are arranged peripherally in direct contact with the dentin
• Radicular pulp: Located in the roots of the teeth. matrix. This close relationship between odontoblasts and
dentin is referred to as the dentin-pulp complex. Dentin
Coronal pulp resembles the shape of the outer surface of and pulp are embryologically, structurally and functionally
the crown dentin. Coronal pulp has six surfaces: the roof related. Figure 2.1 shows the diagrammatic representation
or occlusal, the mesial, the distal, the buccal, the lingual of histologic section of dentin-pulp complex. The histology
and the floor. The protrusions of the pulp that extend into of pulp is explained in detail later in this chapter.
6 Short Textbook of Endodontics
Certain growth factors such as Epidermal Growth Factor (EGF) – Cervical loop: Rim of enamel organ where outer and
and others initiate tooth development
↓
inner enamel epithelia join.
Specific cells of dental lamina form Enamel organ in – Enamel knot and cord: Cells in center of enamel
response to those factors organ are densely packed and form the enamel knot.
At the points of initiation, enhanced proliferative activity Vertical extension of enamel knot into dental papillae
ensues and successively results into the different stages of is called Enamel cord.
tooth development. According to the shape of the epithelial Enamel knot serves as a transient critical signaling center
part of tooth germ, they are called as Bud, Cap and Bell that has dense population of epithelial cells without any
stages (Morphologic Stages): proliferative activity and marked by expression of multiple
• Bud stage is the initial stage of tooth development during signaling molecules. These signaling molecules are critical
which the epithelial cells of dental lamina proliferate for proper development of tooth organ.
and produce a budlike projection into adjacent ecto- • Bell stage: As the cells forming the loop continue to
mesenchyme (Fig. 2.2). proliferate, there is further invagination of the enamel
Differentiation of dental lamina organ into mesenchyme and the enamel organ assumes
↓ a bell shape (Figs 2.4 and 2.5).
Round or ovoid swellings arise from basement membrane at ten different
points corresponding to future positions of deciduous teeth-primordia of
enamel organs (the tooth buds)
Fig. 2.2 Diagrammatic representation of bud stage Fig. 2.4 Diagrammatic representation of early bell stage
8 Short Textbook of Endodontics
- Odontoblasts are tall and columnar with the • Structure: Cell-rich zone is more prominent in coronal
nuclei polarized towards the center of the pulp pulp than the radicular pulp.
arranged in about 6–8 layers in the region of the – Ground substance forms the matrix that surrounds
pulp horns. and supports the cellular and vascular elements of
• Odontoblasts in Radicular pulp: pulp. It is composed of proteoglycans, glycoproteins
– Odontoblasts are cuboidal in midportion of radicular and water.
pulp – Fibroblasts are present in large numbers in the cell-
– Have less crowded arrangement in root and spread rich zone especially in coronal portion. Fibroblasts
out laterally are stellate-shaped cells with ovoid nuclei and
– Odontoblasts are squamous or flattened in the apical cytoplasmic process.
portion of the pulp. – Two types of fibers are found:
Arranged in 2–3 layers in midportion of pulp and i. Elastic fibers that are found in the walls of the
in a single layer in the apical pulp. arterioles.
• Function: Production and deposition of dentin is the ii. Collagen fibers secreted by fibroblasts found in
primary function of odontoblasts. the body of the pulp.
In young pulp, collagen fibers are small and occur
Cell-Free Zone of Weil (Fig. 2.6) in diffuse pattern and in older pulp, they are found in
large bundles usually found in central region.
• This is a narrow zone about 40 um in width, located The apical third of mature pulp contains more
immediately subjacent to the odontoblastic zone. collagen fibers than the coronal third.
• Constituents: – Undifferentiated mesenchymal cells are stellate-
– Blood capillaries shaped with a large nucleus and little cytoplasm.
– Rich network of unmyelinated nerve fibers called as They are located around the blood vessels in the
plexus of Rashkow cell-rich zone.
– Slender cytoplasmic processes of fibroblasts – Macrophages are blood monocytes that have
– Ground substance. migrated into the pulp tissue.
• Structure: Its presence or absence depends on functional • Functions:
status of pulp. It may be completely absent in young – Ground substance acts as a barrier against the spread
pulps during dentinogenesis and in older pulps due to of bacteria. It is a transport medium for metabolites
reparative dentin formation. and cellular waste products.
It is more prominent in coronal pulp. – Fibroblasts bring about formation as well as
• Functions: degeneration of collagen fibers. They can bring about
– Capillaries are involved in the nutrition of deposition of calcified tissue. They have the potential
odontoblasts especially during dentinogenesis and for reparative dentin formation.
periods of inflammation – Collagen fibers secreted by fibroblasts support the
– Rashkow’s plexus involved in the neural sensation body of pulp and those secreted by odontoblasts
of pulp form the dentinal matrix. Collagen fibers in the
– Ground substance involved in the metabolic apical third of root protect the neurovascular bundle
exchanges of the cells and it has the role in limiting from injury.
the spread of infection due to its consistency. – Undifferentiated mesenchymal cells can differentiate
into fibroblasts, odontoblasts, macrophages or
Cell-Rich Zone (Fig. 2.6) osteoclasts to bring about repair and regeneration.
remove extravasated red blood cells, dead cells and Arterioles, Venules and Capillaries and
foreign bodies from the tissue. Few macrophages are Arteriovenous Anastomoses
involved in immune reactions by processing antigen
and presenting it to the memory T cells. • Blood from the arteries enters the tooth by way of
• Dendritic cells: They are the accessory cells of the Arterioles having diameter of 100 µm or less and the
immune system and are termed as antigen presenting Venules having diameter of 200–300 µm leave the tooth
cells. They induce T-cell dependent immunity. through the apical foramen.
• Lymphocytes: T-lymphocytes are mainly found. Smaller vessels may enter the pulp via accessory or
B-lymphocytes are scarce. Lymphocytes appear at lateral canals. But the tooth does not have a collateral
the site of injury after invasion by Neutrophils (PMN alternative blood supply.
Leukocytes) • From the root pulp, arterioles pass to supply the coronal
• Mast cells: They are found in relation to blood vessels in pulp in a straight direction so that 90o branching patterns
chronically inflamed pulps. Mast cell granules contain develop as shown in Figure 2.7.
heparin (anticoagulant) and histamine (inflammatory – They spread laterally towards the odontoblast layer
mediator) and other chemical factors. and form a capillary plexus beneath the odontoblast
layer.
Undifferentiated Mesenchymal Cells – Terminal capillary networks are most important
vessels in the pulp and carry out the following
• They are the primary cells in very young pulp, but a functions: Maintains pulp homeostasis by:
few undifferentiated cells remain in the pulps after a. Transport of nutrients and gas to cells
root development. Their number decreases in older b. Removal of waste products and CO2 from the cells.
pulps. • Coronal portion of the pulp has nearly twice the capillary
• They are believed to be totipotent cells that can blood flow than the root portion being greatest in the
differentiate into odontoblasts, fibroblasts or macro region of Pulp Horns.
phages when need arises. Also called Reserve cells. • From the capillary networks, blood passes into post-
• These cells are found scattered throughout the central capillary venules and into larger venules.
pulp along pulp vessels in cell-rich zone. These venules have thin and discontinuous muscular
• They appear polyhedral in shape with peripheral coat for the movement of fluid in or out of the vessel.
processes and large oval staining nucleus. • Arteriovenous anastomosis connects the arteriole
directly to a venule bypassing the capillary bed. These
Fibers are small vessels having diameter of 10 µm. They may
Arterial Supply
• Arterial supply of the pulp is from the posterior superior
alveolar arteries and
– Infraorbital artery
– Inferior alveolar branch of internal maxillary arteries. Fig. 2.7 Diagrammatic representation of pulpal blood supply
12 Short Textbook of Endodontics
play a role in regulation of blood flow. May be found in in close association with the blood vessels of the pulp
coronal and radicular portions of pulp, more frequent and many are sympathetic in nature.
in radicular portion. A-fibers transmit fast pain which is sharp and piercing.
• ‘U’-Turn loops filled with streaming blood may be found C-fibers transmit slow pain which is dull, aching pain.
in the pulp vascular network that shunt blood away from • Apart from sensory fibers, sympathetic fibers from the
area of injury or inflammation thus preventing injury to superior cervical ganglion appear with the blood vessels
microcirculation. when the vascular system is established in the dental
• Changes in pulpal blood flow can be measured using papilla. In adult tooth, sympathetic fibers form plexuses
the laser Doppler flowmeter. around the pulpal arterioles usually.
• Pulpal blood flow may be affected by change in posture. • A network of nerves located adjacent to the cell-rich
Change of posture from standing to supine position zone formed by peripheral axons is called plexus of
causes increase in blood flow resulting in elevated pulpal Raschkow. A-delta fibers lose their myelin sheath at the
tissue pressure sufficient to activate pulpal nocireceptors odontoblastic layer forming this plexus.
to initiate spontaneous pulpal pain. Formation: Nerve bundles along with the blood vessels pass from
• The stealing theory of pulpal blood flow: Most of the radicular pulp to coronal pulp
vascular resistance regulating the pulpal blood flow is ↓
located in the venules and also outside the pulp. As a They branch into smaller bundles beneath the cell-rich zone
↓
result, Ramify into plexus of single-nerve axons called the plexus of Raschkow
Changes in blood flow in surrounding tissues ↓
such as gingiva, alveolar bone and PDL In this plexus, A-fibers emerge from their myelin sheaths and branch further
↓ to form sub-odontoblastic plexus within the Schwann cells from which
Causes changes in pulpal blood flow terminal axons exit and pass between odontoblasts as free nerve endings.
According to Poiseuille law, “Any vasodilatation in tissues that receive • Pain sensation caused by external stimuli in the tooth is
their blood supply through the side branches of the end arterioles mediated by large myelinated fibers.
feeding the pulp will, steal blood pressure from the pulp.” • Certain neurotransmitters are present in the nerves of the
Thus, vasodilatation of alveolar bone, periodontal ligament or gingiva dental pulp such as substance P, 5-Hydroxytryptamine,
↓
Fall in arterial blood pressure of the Vasoactive Intestinal peptide, prostaglandins, acetyl
arterioles feeding the pulp choline, norepinephrine.
• Sensory response in the pulp cannot differentiate
• Dental pulp is called as the LOW COMPLIANCE SYSTEM between heat, touch, pressure or chemicals because
because it is encased in rigid structures namely enamel, pulp organs lack receptors specific to different stimuli.
dentin and cementum. Due to limited ability of pulp As a result, the unique feature of dentin receptors is that
to expand, any vasodilatation and increased vascular environmental stimuli always elicit pain as a response.
permeability occurring during inflammation cause an • A-delta fibers get stimulated first when Electric pulp
increase in pulpal hydrostatic pressure and thus reduced tester is used. C-fibers also get stimulated if intensity of
pulpal blood flow. stimulus is increased.
A mind-map to remember all points of blood supply A mind-map to remember all points of Nerve supply
of pulpal tissues (Fig. 2.8). of pulp is given in Figure 2.9.
Fig. 2.8 A mind-map to remember all points of blood supply of pulpal tissues
Lymph vessels draining the pulp and the periodontal – With the developing enamel organ to determine the
ligament of anterior teeth pass to the submental lymph particular type of tooth.
nodes and those of the posterior teeth pass to the • Formative: The cells of the pulp organ produce the
submandibular and deep cervical lymph nodes. dentin that surrounds and protects the pulp. The pulpal
odontoblasts play a role in developing the organic matrix
WHAT ARE THE FUNCTIONS OF THE PULP? and calcification during dentin formation.
• Inductive: The pulp anlage interacts: • Nutritive: The blood vascular system of the pulp
– With the oral epithelial cells leading to differentiation nourishes the surrounding avascular dentin through
of the dental lamina and enamel organ formation. odontoblasts and their processes.
14 Short Textbook of Endodontics
• Sensory: Although the pulp is encased by protective WHAT IS THE MORPHOLOGY AND
layer of dentin, which in turn is covered with enamel, HISTOLOGY OF PERIRADICULAR TISSUES?
the pulp is quite sensitive to different external stimuli
such as heat, cold, pressure, chemicals and mechanical Periradicular tissues include (Fig. 2.11):
trauma. The response is always pain irrespective of the • Cementum
type of stimulus due to lack of specific receptors related • Periodontal ligament
to those stimuli. The nerves in the pulp initiate reflexes • Alveolar process
that control circulation in the pulp.
• Defensive or reparative: The dental pulp responds to Cementum
mechanical, thermal, chemical or bacterial irritation Cementum is hard, bone-like calcified tissue structure
by producing reparative dentin and mineralizing any covering the roots of the teeth.
affected dentinal tubules (Sclerosis) to wall off the pulp
from the source of irritation. In response to bacterial Types
infection, pulp elicits inflammatory and immunologic • Cellular cementum
reaction. The macrophages, lymphocytes, neutrophils, • Acellular cementum.
monocytes, plasma and mast cells of the pulp help in
the process of repair of the pulp. Cellular Cementum
A mind-map listing all points of dental pulp is given • It contains cells called cementocytes and deposited
in Figure 2.10. usually in the apical third of root.
The Dental Pulp and the Periradicular Tissues 15
Periodontal Ligament
The periodontal ligament is a dense, fibrous connective
tissue surrounding the roots of the teeth and occupying the
space between the cementum and the alveolar bone and
is continuous with the pulp and the gingiva. It attaches the
root to the surrounding tissues.
Two important components of periodontal ligament
are:
1. Cells
2. Fibers
BIBLIOGRAPHY
1. Bhaskar SN. Orban’s Oral Histology and Embryology, 11th edn. 3. Grossman L, Oliet S, Del Rio C. Endodontic Practice, 11th edn.
Mosby, 2001.pp.28-48,pp.139-79. Varghese Publication; 1991.pp.29-58.
2. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis: 4. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics 6, 6th edn.
Mosby, 2006.pp.460-513. BC Decker Inc, Hamilton; 2008.pp.118-50.
Morphology and Internal
3
CHAPTER
This chapter describes the morphology and internal anatomy of teeth and their root canal systems
You must know
• What are the Anatomic Components of the Root Canal System?
• What are the Regressive Changes that Occur in the Anatomy of Root Canal System?
• What are the Different Types of Root Canal Systems in any Root?
• What is the Anatomy of the Apical Portion (Apical 1/3rd) of the Root Canal?
• Which are the Anatomic Complexities that can Occur in Root Canal System?
• What is Isthmus and what is its Role during Endodontic Surgical Procedure?
• What are the Possible Developmental Anomalies and Variations in the Anatomy of Root
Canal System?
• What is the Morphology of the Root Canal System of the Individual Teeth?
• Canal orifices: The openings in the floor of the pulp mandibular first molar almost always has two canals;
chamber that lead into the root canals are called as the its distal root occasionally has two canals.
canal orifices. They are not separate structures, but are – According to Meyer, roots which are round and
continuous with both pulp chamber and root canals. cone-shaped, usually contain only one canal but
roots which are elliptical and have flat or concave
Components of the Root Canal (Fig. 3.1) surfaces frequently have more than one canal.
• Apical foramen: A funnel-shaped opening where the
• Principal/main root canal: root canal exits is called as the apical foramen. Besides
– The root canal is that portion of the pulp cavity from there are numerous geometrical configurations and
the canal orifice to the apical foramen. intricacies along the length of the root canal. Apical
– For convenience, the root canal is divided into three foramen may be located in the center of root apex or
sections namely: coronal, middle and apical thirds. may exit on the mesial, distal, labial or lingual surface
– Usually the root canal does not extend straight along of the root slightly eccentrically.
the entire length of the root. Either a curvature or a • Accessory, lateral and furcation canals: Minute canals
constriction is present before the apex is reached. extending in horizontal, vertical or lateral directions
– The shape of the root canal usually conforms to the from pulp to the periodontium are called as accessory
shape of the root. If there is curvature in the root, canals. Accessory canals consist of connective tissue and
usually the root canal follows this curve. vessels but they do not supply the pulp with collateral
– The curvature may be: circulation.
a. Gradual curvature of the entire canal. Accessory canals that branch to the lateral surface of
b. Sharp curvature of canal near the apex. the root are called as lateral canals. These may be visible
c. Gradual curvature of canal with straight apical on radiograph. Canals occurring in the bifurcation
ending. or trifurcation of multirooted teeth are called as the
d. Double curvature of the canal (S-shaped canal). furcation canals.
– Usually, the number of root canals corresponds Formation: Accessory canals are formed as a result
to the number of roots. But a root can have more of entrapment of periodontal vessels in Hertwig’s
than one canal. For example, the mesial root of Epithelial Root Sheath (HERS) during calcification.
Furcation canals are formed as a result of entrapment
of periodontal vessels during the fusion of diaphragm
that becomes pulp chamber floor.
Clinical significance: Accessory, lateral and furcation
canals can serve as avenues for the passage of irritants,
primarily from the pulp to the periodontium.
• Accessory foramina: Openings of accessory and lateral
canals in root surface are called as accessory foramina.
• Apical delta: A pyramidal or pointed structure made
of multiple fine channels in the apical third of the root
through which the blood vessels and nerves pass is
called apical delta. Figure 3.2 shows the diagrammatic
representation of the apical delta.
For convenience, the root canal is divided into three
sections: coronal, middle and apical thirds as shown in
Figure 3.1.
• Portals of exit (POE): The openings from the root canal
system to the PDL space through which the micro-
Fig. 3.1 Diagram showing components of root canal system.
A: Coronal pulp; B: Radicular pulp/Principal root canal; a: Pulp horn;
organisms and the potential Endodontic breakdown
b: Roof of pulp chamber; c: Canal orifice; d: Floor of pulp chamber; products may pass are referred to as Portals of Exit
e: Lateral canal; f, g, h: Portals of Exit (POE) (POE).
Morphology and Internal Anatomy of the Root Canal System 21
Fig. 3.3 Characteristics of root canal system in young person Fig. 3.4 Characteristics of root canal system with increasing age
WHAT ARE THE REGRESSIVE CHANGES THAT WHAT ARE THE DIFFERENT TYPES OF ROOT
OCCUR IN THE ANATOMY OF ROOT CANAL CANAL SYSTEMS IN ANY ROOT?
SYSTEM?
The canals within the root, may branch, divide and
See Figures 3.3 to 3.5. rejoin.
22 Short Textbook of Endodontics
A C
B D
Figs 3.5A to D Diagrams showing age changes in the root canal system in order: a: Pulp horns: High pulp horns go on receding with increasing
age; b: Pulp chamber: Large and wide pulp chambers become smaller and shorter; c: Root canals: Wider root canals become narrower due
to deposition of secondary and reparative dentin; d: Apical foramen: Broad open apex of immature tooth closes and becomes narrow and
forms an apical stop; e: Pulp stones: Calcification is seen in older pulps and few pulps with chronic infection. Calcification starts in the pulp
chamber and proceeds apically
Classification of Root Canal Systems (Fig. 3.6) • Type IV: One canal leaving the pulp chamber and
dividing short of the apex into two separate, distinct
The possible configurations of the root canal systems as canals with separate apical foramina (1-2) (Fig. 3.6D)
given by Weine include: Weine’s classification is the first clinical classification of
• Type I: Single canal extending from the pulp chamber more than one canal system in a single root.
to the apex (1) (Fig. 3.6A) Later, Vertucci et al gave the classification categorizing the
• Type II: Two separate canals leaving the pulp chamber root canal system into following eight types:
and joining short of the apex, to form one canal (2-1) 1. Type I: Single canal extending from the pulp chamber
(Fig. 3.6B) to the apex (1) (Fig. 3.7)
• Type III: Two separate, distinct canals extending from 2. Type II: Two separate canals leaving the pulp chamber and
the pulp chamber to the apex (2) (Fig. 3.6C) joining short of the apex, to form one canal (2-1) (Fig. 3.8)
Morphology and Internal Anatomy of the Root Canal System 23
A B C D
Figs 3.6A to D Weine’s classification of root canal systems
3. Type III: One canal leaving the pulp chamber and 7. Type VII: One canal leaving the pulp chamber and
dividing into two canals in the root. The two root canals dividing into two canals and then rejoining to form one
then merge to exit as one canal (1-2-1) (Fig. 3.9) canal in the body of the root, and then finally redivides
4. Type IV: Two separate, distinct canals extending from into two distinct canals short of the apex (1-2-1-2)
the pulp chamber to the apex (2) (Fig. 3.10) (Fig. 3.13).
5. Type V: One canal leaving the pulp chamber and 8. Type VIII: Three separate, distinct canals extending from
dividing short of the apex into two separate, distinct the pulp chamber to the apex (3) (Fig. 3.14).
canals with separate apical foramina (1-2) (Fig. 3.11) The only tooth that has been found with all eight possible
6. Type VI: Two separate canals leaving the pulp chamber, configurations is the maxillary 2nd premolar.
and joining in the body of the root to form one canal,
which redivides short of the apex to exit as two distinct According to Vertucci’s classification:
canals (2-1-2) (Fig. 3.12). • Types I, II, III show One canal at apex
24 Short Textbook of Endodontics
• Types IV, V, VI, VII show Two canals at apex determine the number and location of orifices on the
• Type VIII shows Three canals at apex. pulp chamber floor which have been described in detail
in Chapter 13: Endodontic Access Cavity Preparation.
Vertucci’s Findings Those guidelines should be followed.
• Magnification and illumination aids such as dental
• Whether the canals join or remain as separate canals, is loupes and dental operating microscope are valuable
determined by the proximity of the canal orifices. aids that improve visualization and greatly reduce the
• Joining of canals: If orifices are less than 3 mm apart, chances of missing root canals or any variable anatomy.
canals usually are joined together. • Other orifice location aids such as Champagne bubble
As the distance between the orifices decreases, canals test using sodium hypochlorite and other aids have
are found to join more coronally. been described in Chapter 13: Endodontic Access Cavity
• Separation of canals: If the distance between the orifices Preparation.
is more than 3 mm, the canals tend to remain separate
through their entire length. WHAT IS THE ANATOMY OF THE APICAL
PORTION (APICAL 1/3rd) OF THE ROOT CANAL?
Some of the Practical Hints to Determine
The apical portion of the root contains three anatomic and
the Type of Canal System Clinically
histologic landmarks (Fig. 3.15):
• It is important to have knowledge of different variations I. Apical foramen or major apical diameter.
that can occur in the root canal anatomy including the II. Apical constriction or minor apical diameter.
possibility of finding additional canals than the usual III. Cementodentinal junction (CDJ).
for a given tooth.
• Pretreatment radiographs taken in two-three different Apical Foramen or Major Apical Diameter
angulations gives an idea of the internal anatomy of the
(Fig. 3.15b)
tooth and the number of root canals.
• Follow the “dentinal map” which is the road-map to the • Cohen has defined it as follows:
root canal system and preserve the pulpal floor. “Apical foramen is the circumference or rounded edge,
• Location of canal orifice on pulpal floor can indicate the like a funnel or crater, that differentiates the termination
number of canals present as follows:
– Canal located in center of the pulpal floor may
indicate that one canal is present.
– Canal orifices located less than 3 mm apart: Indicates
tendency to join/unite.
– Canal orifices located more than 3 mm apart may
indicate tendency to remain separate.
• On radiograph, sudden disappearance or narrowing of
canal (fast-break guideline): Indicates bifurcation of root
canal.
• When the first file inserted into distal canal of a
mandibular molar, points in buccal or lingual direction:
may indicate 2 distal canals are present.
• When two canals join in the root to form one canal,
lingual/palatal canal has direct access to apex.
• When one canal separates into two canals, configuration
of separated canals is in the shape of letter ‘h’, where
(given by Slowey)
– Buccal canal is straight portion of ‘h’
– Lingual canal generally is the one that splits from the
Fig. 3.15 Diagrammatic representation of anatomy of apical third
main canal at a sharp angle. of root. a: Cementum; b: Apical foramen; c: Cementodentinal
• Krasner and Rankow have given certain guidelines junction (CDJ); d: Major constriction; e: Minor constriction; f: Apical
or laws of pulp chamber anatomy to help clinicians constriction
26 Short Textbook of Endodontics
of the cemental canal from the exterior surface of the to be 0.5 mm in young persons and 0.67 mm in older
root”. individuals.
• Generally, the apical foramen does not exit at the apex, • The space that occurs between the major and minor
it may be about 0.5 – 3 mm offset from center. apical diameters, i.e. between the AF and AC is funnel
• The apical foramen may not always be located in the shaped, described as ‘hyperbolic’ shape or ‘shape of the
center of the root apex and it may be on mesial, distal, morning-glory’.
labial or lingual surface of the root.
• In immature tooth with open apex, the apical foramen Cementodentinal Junction (CDJ) (Fig. 3.15c)
is funnel-shaped filled with periodontal tissue which is
replaced by dentin and cementum as the root develops • It is the junction where cementum meets dentin.
so that the apical foramen becomes narrower. Root • At CDJ, pulp tissue ends and periodontal tissues begin.
canals can take various courses and accordingly the • CDJ is approximately 1 mm from the apical foramen.
apical foramen is located. Figures 3.16A to D show • The CDJ is considered to be the ideal point of termination
different curvatures of root canals and the locations of for the preparation and obturation of the root canals.
the apical foramina.
• Average size of apical foramen in maxillary permanent Anatomy of Root Apex
teeth is 0.4 mm diameter and that of mandibular
permanent teeth is 0.3 mm. The apical opening may not Figure 3.15 shows diagrammatic representation of anatomy
always be found in the center of the apex. Frequently of root apex.
two or more foramina are found separated by a portion A mind-map to remember all points of landmarks in
of dentin and cementum or by cementum only. apical portion of canal is illustrated in Figure 3.17.
Apical Constriction or Minor Apical Diameter WHICH ARE THE ANATOMIC COMPLEXITIES
(Fig. 3.15f) THAT CAN OCCUR IN ROOT CANAL SYSTEM?
• Apical constriction is the part of the root canal with the
smallest diameter. Anatomic complexities of root canal system include:
• Apical constriction is generally 0.5 – 1.5 mm inside the • C-shaped canals
apical foramen. • Additional canals
• Apical constriction is delicate and should be maintained. • Fins, deltas, loops, intercanal connections, etc.
Over-instrumentation violates and breaks this
constriction resulting in irritation of periapical tissues ‘C’-shaped Canals (Fig. 3.18)
and over-extended root canal filling may occur. • Roots and their root canals with their cross-sectional
• The mean distance between the major and minor apical morphology C-shaped are called as C-shaped canals.
diameters, i.e. between the AF and AC has been found • C-shaped canal first documented in Endodontic
literature by Cooke and Cox in 1979.
• C-shaped canals result from fusion of the mesial and
distal roots on either the buccal or the lingual root
surface. Failure of fusion of the Hertwig’s epithelial root
sheath to fuse on buccal or lingual root surface forms
C-shaped roots that contain C-shaped canals.
• Occurs most commonly in mandibular second molars
but may also be seen in mandibular first molar, maxillary
first and second molars.
• C-shaped root canal system has single, ribbon-shaped
A B C D orifice that has an arc of 180 degrees or more.
Figs 3.16A to D Various courses of the root canals and the location • It starts at mesiolingual line angle of pulp chamber and
of the apical foramina: (A) Curvature in the apical third of the root goes around buccal or lingual and ends at distal aspect
canal and apical foramen distant from the root apex; (B) Curvature
of pulp chamber.
in the apical third of the root canal and apical foramen near the
apex; (C) Constriction in the root canal as the apical foramen is • Classification of C-shaped canals:
approached; (D) Double curvature of the root canal and apical I. Based on number of canals that leave from orifice
foramen distant from root apex and reach apex (Flow chart 3.1)
Morphology and Internal Anatomy of the Root Canal System 27
Fig. 3.17 A mind-map to remember all points of landmarks in apical portion of canal
• Sometimes the C-shaped groove runs connecting two or • Other complexities: Fins, deltas, loops, intercanal
three orifices such as mesiobuccal and distal orifices or connections, etc.
mesiobuccal and distobuccal and distolingual orifices
with the mesiolingual orifice remaining separate in WHAT IS ISTHMUS AND WHAT IS ITS ROLE
mandibular first molar. These canals at the apical
DURING ENDODONTIC SURGICAL PROCEDURE?
portion may end into separate apical foramina or may
get merged to exit as single canal. Due to a number When two or more canals are present in the root, a narrow
of anatomic variations seen in the C-shaped canal ribbon-shaped communication that occurs between the
morphology, the cleaning, shaping and obturation of root canals containing pulp or pulpally derived tissues is
these teeth becomes difficult. called an isthmus (Fig. 3.22A).
Figures 3.21A and B show preoperative and post- Kim et al classified isthmi into 5 types that can be found:
operative radiographs of mandibular second molar with 1. Type I: An incomplete isthmus with a faint
C-shaped canal. communication between the two canals (Fig. 3.22B).
• Presence of additional canals: There is always a possibility 2. Type II: A complete isthmus with a definite
of additional root canals than that are normally found, communication between the two canals (Fig. 3.22C).
in any tooth. If these canals are missed, it results in 3. Type III: A very short, complete isthmus between the
incomplete debridement causing Endodontic failure. two canals (Fig. 3.22D).
4. Type IV: A complete or an incomplete isthmus that
occurs between three or more canals (Fig. 3.22E).
5. Type V: Two or three canal openings without visible
communication between the canals (Fig. 3.22F).
A B C
D E F
Figs 3.22A to F (A) Diagram showing enlarged view of ribbon-shaped communication between root canals: Isthmus;
(B) Type I; (C) Type II; (D) Type III; (E) Type IV; (F) Type V
Fig. 3.23 Diagrammatic representation of gemination Fig. 3.24 Diagrammatic representation of fusion of teeth
• Fusion: It is a developmental anomaly caused by union • Dilaceration: It is an angulation or a sharp bend or curve
of two normally separated tooth germs. The tooth in the root or crown of a formed tooth caused due to
may have separate or fused root canals (Figs 3.24 and trauma during tooth development. This curvature needs
3.25). to be recognized on preoperative radiograph to prevent
• Concresence : It is the fusion of teeth after root formation procedural errors (Fig. 3.27).
is completed. Teeth are joined by cementum only (Fig. • Talon’s cusp: It is an anomalous structure that resembles
3.26). an eagle’s talon, that projects lingually from the
Morphology and Internal Anatomy of the Root Canal System 31
Fig. 3.25 Intraoral periapical radiograph showing fusion of lower Fig. 3.27 Diagrammatic representation of dilaceration in the apical
central and lateral incisor teeth of both left and right sides appearing third of the roots of a maxillary molar
as wide central teeth having fused pulp chambers and root canals
(Courtesy of Dr Mansi Shah, Dentoview-Advanced Dental Imaging
Center)
Fig. 3.26 Diagrammatic representation of concresence of maxillary Fig. 3.28 Intraoral periapical radiograph showing dens in dente in
second and third molars maxillary left central incisor (Courtesy of Dr Mansi Shah, Dentoview
Advanced Dental Imaging Center)
cingulum area of maxillary or mandibular permanent Figure 3.28 shows a radiograph showing dens in dente
incisor. There is a deep developmental groove where in maxillary left central incisor.
the talon’s cusp blends with the sloping lingual tooth Three types of Dens in Dente include: (Fig. 3.29)
surface that consists of a horn of pulp tissue. Exposure – Type I: It is minor type, lined by enamel that occurs
of pulp horn necessitates Endodontic therapy. within the crown and not extending beyond
• Dens invaginatus/dens in dente: It is a developmental Cemento enamel junction (CEJ).
variation caused by invagination within the crown or – Type II: It consists of enamel lined blind sac that
root of the lingual surface of tooth before calcification invades the root and may connect with the dental pulp.
has occurred. Permanent maxillary incisors are the teeth – Type III: It is the severe type which extends to the
more frequently involved, although may occur in other root and opens in the apical region but without
anterior teeth as well. connection with the dental pulp.
32 Short Textbook of Endodontics
Fig. 3.29 Diagrammatic representation of dens in dente Fig. 3.30 Diagrammatic representation of taurodontism in
types I, II, and III mandibular molars (Courtesy of Dr V.S. Mohan)
• Dens evaginatus: It appears as an accessory cusp or a dentin formation with abnormal pulpal morphology.
globule of enamel on occlusal surface between buccal Roots are malformed in both the dentitions. In Radicular
and lingual cusps of premolars, rarely on molars, canines dentin dysplasia, obliterated pulp chambers are seen
and incisors. This extra cusp may contribute to pulp in both the dentitions. In coronal dentin dysplasia,
exposure with subsequent infection following occlusal obliterated pulp chambers in deciduous teeth and
wear or fracture. abnormally large pulp chambers in permanent teeth
• Taurodontism: It is a dental anomaly in which the occur.
body of tooth is enlarged at the expense of the roots. • Palatal developmental groove: It originates from palatal
On radiograph, the involved tooth appears rectangular surface usually the cingulum of maxillary lateral incisor
in shape rather than taper toward the roots. The pulp and ends apically at various levels of root.
chamber is extremely large and the usual constriction • Additional root canals than the usual may be present.
at the cervical of tooth is lacking and the roots are Figures 3.32A and B show radiographs of maxillary
exceedingly short. Bifurcation/trifurcation may be lateral incisor with four canals.
present only few millimeters above the root apex.
Figure 3.30 shows diagrammatic representation of WHAT IS THE MORPHOLOGY OF THE ROOT
taurodontism in mandibular molars and Figures 3.31A CANAL SYSTEM OF THE INDIVIDUAL TEETH?
and B show the pre- and postoperative radiograph of
pulpally involved mandibular molar with taurodontism. Maxillary Central Incisor (Fig. 3.33)
• Supernumerary roots: Extra roots than the usual • Average length of tooth: 22.5 mm
may be present. Teeth that usually have single root, • Usual number of roots: 1
particularly mandibular premolars and canines, • Usual number of root canals: 1 (Lateral accessory canals
often have two roots. Molars also may exhibit one or may be present)
more supernumerary root. Additional roots must be • Root curvature: Mostly straight, but may be curved to
recognized on preoperative radiograph to accomplish labial or distal.
Endodontic treatment properly.
• Dentinogenesis imperfecta (Hereditary opalescent Morphology of Root Canal System
dentin): In type I and type II dentinogenesis Imperfecta,
there is partial or total obliteration of the pulp chamber Morphology of pulp chamber
and root canals by continued formation of dentin. • Pulp chamber wider mesiodistally than buccolingually
• Dentin dysplasia: Dentin dysplasia is a hereditary • Three pulp horns present in newly erupted central
disease characterized by normal enamel but atypical incisor
Morphology and Internal Anatomy of the Root Canal System 33
A B
Figs 3.31A and B Taurodontism seen in a mandibular molar:
(A) Preoperative radiograph showing deep caries involving the pulp
(B) Postobturation radiograph (Courtesy of Dr Roheet Khatavkar) Dotted line shows the outline for access cavity preparation
A B A B
Figs 3.32A and B Preoperative and postoperative radiographs Figs 3.34A and B Preoperative and postoperative radiographs of
showing maxillary lateral incisor with four canals which were maxillary central incisor tooth (Courtesy of Dr Roheet Khatavkar)
located, negotiated, cleaned and shaped and obturated (Courtesy of
Dr V.S. Mohan)
• Since there is single canal usually, the division between Possible Variation and Anomalies
pulp chamber and root canal is indistinct
• Floor is oval generally. • More than one main canal may be present.
• Dens invaginatus.
Morphology of root canals • Shovel shaped incisor crowns.
• Cross-section at CEJ level is generally triangular in young • Fusion, gemination.
teeth and oval in older teeth
• Cross-section at apical level gradually becomes round. Maxillary Lateral Incisor (Fig. 3.35)
Figures 3.34A and B show the preoperative and
postoperative radiographs of maxillary central incisor • Average length of tooth: 21 mm
tooth. • Usual number of roots: 1
34 Short Textbook of Endodontics
Possible Variation and Anomalies • Average length of tooth: 26 mm (Longest root in dentition
of approximately 17 mm length)
• Two roots may be present usually associated with a • Usual number of roots: 1
developmental radicular palatal groove. • Usual number of root canals: 1 (Lateral accessory canals
• Dens invaginatus or dens in dente. may be present commonly in the apical third of the root)
• Fusion, gemination. • Root curvature: Mostly its root gets curved to the distal,
• Additional canals may be present. sometimes straight or may be curved to the labial.
Morphology and Internal Anatomy of the Root Canal System 35
A B
Dotted line shows the outline for access cavity preparation
Figs 3.38A and B Preoperative and postoperative radiographs
of maxillary canine (Courtesy of Dr Roheet Khatavkar) Fig. 3.39 Maxillary first premolar
36 Short Textbook of Endodontics
A B A B
Figs 3.40A and B Preoperative and postoperative radiographs of Figs 3.41A and B Preoperative and postoperative radiograph
maxillary first premolar tooth (Courtesy of Dr Roheet Khatavkar) of maxillary first and second premolars (Courtesy of Dr Roheet
Khatavkar)
Clinical Considerations
• There is thin layer of bone separating the alveolar socket
of maxillary first premolar from maxillary sinus.
• Buccal root fenestration through the bone leading to
clinical problems such as inaccurate apex location, risk
of irrigation accident, slight permanent apical pressure
sensitivity after root canal therapy.
• Maxillary first premolar is susceptible to mesiodistal
root fracture and fracture at the base of the cusps.
Maxillary Second Premolar (Fig. 3.42) Dotted line shows the outline for access cavity preparation
• Average length of tooth: 21.5 mm Fig. 3.42 Maxillary second premolar
• Usual number of roots: 1
• Usual number of root canals: 1 in most cases, 2 in few
cases
• Root curvature: Mostly the root is distally curved, Morphology of root canals: From floor of pulp chamber
sometimes may get curved to the buccal or to the distal. to the apex the cross-section is oval. When two canals are
present, they are nearly parallel to each other since the tooth
Morphology of Root Canal System has one root usually.
Figure 3.43 shows the postoperative radiograph of
Morphology of pulp chamber maxillary second premolar tooth with one canal.
• Wider buccolingually than mesiodistally Figures 3.44A and B show the preoperative and
• Buccal and palatal pulp horns are present, buccal pulp postoperative radiograph of maxillary second premolar
horn is larger. tooth with two canals.
Morphology and Internal Anatomy of the Root Canal System 37
Clinical Consideration
• Maxillary second premolar is also susceptible to
fractures like the maxillary first premolar.
B
Dotted line shows the outline for access cavity preparation
Figs 3.44A and B Preoperative and postoperative radiographs of
maxillary fist premolar tooth (Courtesy of Dr Shivani Bhatt) Fig. 3.45 Maxillary first molar
38 Short Textbook of Endodontics
– Distobuccal root is mostly straight sometimes it may Figures 3.48A and B show the preoperative and
be curved to the mesial or distal postoperative radiographs of maxillary first molar with
– Palatal root is mostly curved to the buccal sometimes four canals.
it may be straight.
Possible Variation and Anomalies
Morphology of Root Canal System
• Two palatal canals have been reported (Fig. 3.49)
Morphology of pulp chamber • C-shaped canals
• Its buccolingual dimension is widest. • Taurodontism.
• Four pulp horns are present: MB, MP, DB, DP.
• Cross-section of the floor of the pulp chamber is
triangular (Molar triangle) when three canals are present
as shown in Figure 3.46A.
It is rhomboidal when four orifices are present, with
corners corresponding to each of the four orifices
as shown in Figure 3.46B.
• Mesiobuccal orifice lies under the mesiobuccal cusp,
distobuccal orifice lies distal and palatal to the MB
orifice, Palatal orifice is centered palatally. There are two
possible locations of the MB2 orifice: It may lie palatal
and mesial to the main mesiobuccal orifice or it may lie
on a line drawn from the main mesiobuccal orifice to
the palatal orifice. Use of dental operating microscope
or even loupes has resulted in increased prevalence of
A B
clinical detection of MB2 canal.
Figs 3.47A and B Preoperative and postoperative radiographs
Morphology of root canals of maxillary first molar with three canals (Courtesy of Dr Roheet
• The palatal canal is flat and ribbon-like. Khatavkar)
• It has largest dimension and is wider mesiodistally.
• Cross-section of the distobuccal canal is oval in the
coronal two-thirds and round in the apical one-third.
• MB1 and MB2 canals are closely interconnected and
may sometimes merge into one canal.
• Mesiobuccal root has a concavity on its distal aspect.
So the root canal wall becomes thin in that area. As
result, care has to be taken not to instrument the wall
excessively because strip perforation can occur. A B
Figures 3.47A and B show the preoperative and Figs 3.48A and B Preoperative and postoperative radiographs of
postoperative radiographs of maxillary first molar with maxillary first molar with four canals (Courtesy of Dr Shivani Bhatt)
three canals.
A B
Figs 3.46A and B Occlusal view of maxillary first molar with three Fig. 3.49 Occlusal view of maxillary first molar with two palatal
and four canals respectively canals and two mesial canals (MB1, MB2)
Morphology and Internal Anatomy of the Root Canal System 39
Clinical Consideration Figure 3.51 shows the occlusal view of maxillary second
molar with three canals, two canals and one canal.
• Pulp chamber of maxillary first molar lies mesial to the
oblique ridge, so access cavity is usually confined mesial Morphology of root canals
to oblique ridge in most cases. • There may be two, three or four root canals.
• Soreness can occur in maxillary teeth due to sinusitis • When two canals are present (seen in case of fused
or sinusitis can occur due to pulpal disease due to close roots), they are generally parallel and of equal length
proximity of maxillary sinus and because of thin buccal and diameter.
bony plate. Figures 3.52A and B show the postoperative
radiographs of maxillary second molar tooth with three
Maxillary Second Molar (Fig. 3.50) and four root canals respectively.
A B
Figs 3.52A and B (A) Postoperative radiograph of maxillary second molar with three canals (Courtesy of Dr Ajay Bajaj);
(B) Postoperative radiograph of maxillary second molar with four canals (Courtesy of Dr Mrunalini Vaidya)
Clinical Consideration
• Two anatomic structures to which maxillary third
molars lie close are the maxillary sinus and maxillary
tuberosity.
• Since maxillary third molars may be significantly tipped
to distal, buccal or both, there can be great access
problem.
• Limited mouth opening can make root canal therapy
almost impossible in maxillary third molar teeth.
Dotted line shows the outline for access cavity preparation Mandibular Central Incisor (Fig. 3.55)
Fig. 3.53 Maxillary third molar • Average length of tooth: 20.8 mm
• Usual number of roots: 1
• Usual number of root canals: 1 or 2 canals which usually
exit into a single apical foramen
• Root curvature: Mostly it is straight, sometimes it may
be curved to the distal or labially curved.
• When two root canals (buccal and lingual) are present, Clinical Consideration
they usually join at the apical portion. Sometimes they • Second canal is found lingual to the main canal. It should
exit as two separate canals (Fig. 3.56). not be missed.
Figure 3.57 shows the postoperative radiograph of • Due to lingual inclination of apex of mandibuar central
mandibular central and lateral incisor teeth. incisor, surgical access may be difficult to achieve.
Fig. 3.56 Postoperative radiograph of mandibular central incisor Fig. 3.57 Postoperative radiograph of mandibular central incisors
with two canals (Courtesy of Dr V.S. Mohan) and lateral incisor (Courtesy of Dr Ajay Bajaj)
42 Short Textbook of Endodontics
Dotted line shows the outline for access cavity preparation Dotted line shows the outline for access cavity preparation
Fig. 3.58 Mandibular lateral incisor Fig. 3.59 Mandibular canine
Fig. 3.62 Postoperative radiograph of mandibular first premolar Fig. 3.64 Postoperative radiograph of mandibular first premolar
(Courtesy of Dr Nilesh Kadam) with moderate J-shaped curvature in the apical part of the root
(Dilaceration) (Courtesy of Dr Roheet Khatavkar)
44 Short Textbook of Endodontics
• Due to lingual inclination of crown, access cavity may Possible Variation and Anomalies
need to be extended upto cusp tip, to gain straight • Similar to first premolar but found less often.
line access. Location and negotiation of lingual canal Figures 3.67A and B show the preoperative and
becomes difficult. postoperative radiographs of mandibular second premolar
• Due to close proximity of root apex of mandibular first with additional root and root canals.
premolar to mental canal and foramen, sometimes
periapical radiolucency on radiograph must be Mandibular First Molar (Fig. 3.68)
differenciated from periapical pathology.
• Average length of tooth: 21 mm
• Usual number of roots: 2, sometimes 3
• Usual number of root canals: 3 or 4 usually, sometimes
more
B
Figs 3.67A and B Preoperative and postoperative radiographs of
mandibular second premolar with additional root and root canals
(Courtesy of Dr Roheet Khatavkar)
• Root curvature:
– Mesial root : Mostly gets curved to the distal
sometimes straight.
– Distal root: Mostly straight, sometimes may be
curved to the distal. Fig. 3.69 Occlusal view of mandibular first molar with three, four
and five canals respectively
Morphology of Root Canal System
Morphology of pulp chamber Morphology of root canals
• Four pulp horns are present: MB, ML, DB, DL • Cross-section of all canals is ovoid in cervical and middle
• Roof of pulp chamber is located in cervical third of root thirds and round in the apical third.
and is rectangular in shape. • Mesial root usually has two canals—MB and ML.
• Floor of pulp chamber is located in cervical third of root Sometimes, a third canal called middle mesial (MM)
and is rhomboidal in shape. (Figs 3.69 and 3.71) is found between the two mesial
• Mesiobuccal canal orifice is located under the canals. Mesial root canals are curved; MB canal having
mesiobuccal cusp the greatest curvature.
• Mesiolingual orifice is found just lingual to central • Distal root may have a single canal or two canals—DB
groove and DL are present. Sometimes a third canal middle
• Distal orifice is located distal to buccal groove. distal may be present.
Figure 3.69 shows occlusal view of mandibular first Figures 3.70 to 3.72 show radiographs of mandibular
molar with three, four and five canals respectively. first molar tooth.
46 Short Textbook of Endodontics
A A
B B
Figs 3.70A and B Preoperative and postoperative radiographs of Figs 3.72A and B Preoperative and postoperative radiographs of
mandibular first molar tooth (Courtesy of Dr Shivani Bhatt) mandibular first molar with radix entomolaris (Courtesy of Dr Nilesh
Kadam)
A B Clinical Consideration
Figs 3.71A and B Preoperative and postoperative radiographs
of mandibular first molar with three mesial canals (Courtesy of Dr • Multiple accessory foramina are present in the furcation
Roheet Khatavkar) of mandibular molars.
Morphology and Internal Anatomy of the Root Canal System 47
Morphology of Root Canal System • Multiple accessory foramina are present in the furcation
of mandibular molars
Morphology of pulp chamber • The distal aspect of the mesial root of mandibular second
• Similar to mandibular first molar but more symmetric. molar and the mesial aspect of the distal root have a root
• Smaller size of pulp chamber and canal orifices as concavities where careful instrumentation needs to be
compared to mandibular first molar. done.
• Two mesial orifices located closer together.
• C-shaped canals commonly occur in mandibular second Mandibular Third Molar (Fig. 3.78)
molar. Figure 3.74 shows occlusal view of mandibular
second molar with three canals, four canals, two canals • Average length of tooth: 17.5 mm
and C-shaped canals respectively. • Usual number of roots and root canals: 2
48 Short Textbook of Endodontics
A B
A Figs 3.77A and B Preoperative and postoperative radiographs of
mandibular second molar with C-shaped canal (Courtesy of Dr
Roheet Khatavkar)
B
Figs 3.75A and B Preoperative and postoperative radiographs of
mandibular second molar tooth (Courtesy of Dr Shivani Bhatt) Dotted line shows the outline for access cavity preparation
Fig. 3.78 Mandibular third molar
Clinical Considerations
Fig. 3.76 Postoperative radiograph of mandibular second molar • Anatomic structure that lies close to the roots of
with C-shaped canal (Courtesy of Dr Shivani Bhatt) mandibular third molar is mandibular canal.
Morphology and Internal Anatomy of the Root Canal System 49
A B
Figs 3.79A and B Preoperative and post-operative radiograph of mandibular third molar
showing curved canals (Courtesy of Dr Nilesh Kadam)
4
CHAPTER
This chapter explains how the reaction of pulp to various external stimuli is unique and
describes in detail the reaction of pulp to dental caries and various dental procedures.
You must know
• How is the Response of Dental Pulp Unique and Different from Other Connective Tissues of
the Body?
• Which are the Different External Stimuli that can Affect Dental Pulp?
• How does the Pulp React to Dental Caries?
• How does the Pulp React to Dental Procedures?
– How does the Pulp React to some of the Diagnostic Procedures?
– How does the Pulp React to Treatment Procedures?
• How does the Pulp React to Specific Dental Materials?
HOW IS THE RESPONSE OF DENTAL PULP • Bacteria enter the pulp at a very late stage. Initially there
UNIQUE AND DIFFERENT FROM OTHER is invasion of bacterial products and toxins rather than
CONNECTIVE TISSUES OF THE BODY? bacteria themselves
• Pulp organ lacks specific receptors for different
Pulpal response to external stimuli is unique due to external stimuli, the sensory response is always pain
following reasons: irrespective of the type of stimulus-heat, cold, pressure,
• Pulp is encased within the hard tissues, in an unyielding touch, etc.
low-compliance environment A mind-map to remember all unique features of dental
• Pulp has limited space to expand during inflammation pulp is given in Figure 4.1.
• Pulp has limited portals of entry
• Pulp is an organ of terminal and limited circulation with WHICH ARE THE DIFFERENT EXTERNAL STIMULI
no efficient collateral circulation THAT CAN AFFECT THE DENTAL PULP?
• Pulp is more susceptible to injury and may have Flow chart 4.1 gives the detailed list of external noxious
complicated regeneration due to scarcity of circulation stimuli that can affect the dental pulp causing its
• Even the mature pulp resembles embryonic connective inflammation, necrosis and dystrophy beginning with the
tissue. Therefore, it is relatively rich source of stem cells. most frequent irritant: Micro-organisms. These have been
It has the ability to form dentin throughout life discussed in detail in the next chapter under the possible
• Rich neurovascular supply within the pulp may promote causes of diseases of dental pulp.
the effect of inflammation and can lead to rapid
degeneration and necrosis of pulp HOW DOES THE PULP REACT TO DENTAL CARIES?
• Various dental treatment procedures involve cleaning Dental caries is a polymicrobial disease affecting the dental
and shaping of enamel and dentin, causing further pulp. Bacteria are mainly responsible for causing pulpal
irritation of pulp disease.
The Pulpal Reactions to Caries and Dental Procedures 51
Pathways of Bacterial Invasion of the Pulp Dentin Sclerosis: Decrease in Dentin Permeability
Figure 4.2 shows different pathways through which there is First defense reaction to caries is dentin sclerosis.
invasion of bacteria and toxins into the pulp. This occurs by:
Initially, there is invasion of bacterial toxins and invasion • Increased deposition of intratubular dentin.
by bacteria themselves occurs at later stages of the carious Transforming growth factor-beta 1 (TFG-beta 1) has
process that clinically present as carious exposure. This is been implicated to be mainly responsible for this
because toxins pass through enamel and dentin well ahead reparative dentinogenesis.
of bacteria themselves. • Direct deposition of precipitated mineral crystals into the
Bacterial byproducts and toxins include: narrowed dentinal tubules causing occlusion of tubules.
• Acids and proteinases that dissolve and digest enamel As a result, there is effective decrease in dentin
and dentin permeability occurring in a relatively short period of
• Lipopolysaccharides (LPS) time.
• Lipoteichoic acid (LTA).
Formation of Tertiary Dentin
Reaction of Pulp to Dental Caries
This occurs over a longer period of time as compared to
Pulp exhibits inflammatory reaction in response to bacteria sclerotic dentin.
and their byproducts and toxins. Resultant character of tertiary dentin depends on the
• To protect dental pulp against caries, three basic intensity of stimulus. Either reactionary or reparative dentin
reactions occur in the following sequence: is formed (Fig. 4.3).
– Dentin sclerosis: Decrease in dentin permeability • In response to mild stimulus, resident quiescent
– Formation of tertiary dentin odontoblasts are activated forming reactionary
– Inflammatory and immune reactions. dentin. This mostly is seen in cases where dentin
52 Short Textbook of Endodontics
Flow chart 4.1 Noxious stimuli affecting dental pulp/causes of diseases of dental pulp
Fig. 4.2 Pathways of bacterial invasion into the pulp Fig. 4.3 Diagram showing effect of caries on pulp. a: Bacterial
plaque; b: Outer carious dentin; c: Transparent inner carious dentin;
d: Reparative dentin; e: Pulp
The Pulpal Reactions to Caries and Dental Procedures 53
demineralization has occurred beneath the noncavitated • Chronic hyperplastic pulpitis: In case of primary and
enamel lesion. immature permanent teeth, pulp exposure can result in a
• In response to aggressive stimulus, the subjacent proliferative pulpal response called chronic hyperplastic
odontoblasts die and there is disruption of odontoblast pulpitis characterized by proliferation of exuberant
layer. As a result, there is differentiation of secretory cells inflammatory pulp tissue through the exposure forming
to cause repopulation of the disrupted odontoblast layer pulp polyp.
either by • Pulp necrosis: In case of persistent inflammation,
– Organized tubular reparative dentin or tissue pressure is increased, stasis occurs resulting
– Disorganized irregular fibrodentin. in pulp necrosis. Whether partial or total necrosis of
Sclerotic and tertiary dentin formed provides a physical pulp occurs is determined by possibility of drainage.
barrier to noxious stimuli. In case of pulp open to oral fluids, drainage is possible.
So, partial necrosis is likely to occur. Apical pulp tissue
Inflammatory and Immune Reactions remains uninflammed. But if drainage is not possible,
total necrosis of pulp may occur.
Inflammation Figure 4.5 shows diagrammatic representation of
• Acute inflammation: Polymorphonuclear (PMN) sequel of dental caries, how it affects the dental pulp and
leukocytes reach the area of bacterial involvement to the periradicular area demonstrating caries in enamel
prevent the further dissemination of bacteria deeper and dentin becomes deeper and causes inflammation in
into the pulp.
In case of severe inflammatory process, symptoms
of acute reaction are manifested.
– There is accumulation of inflammatory exudates,
causing pain from pressure on nerve endings.
– As the PMN leukocytes die, there is formation of pus
which further irritates the nerve cells.
• Chronic inflammation: In case of less severe inflam
matory process, PMN leukocytes are replaced by
lymphocytes and plasma cells. The inflammatory
reaction is confined to the surface of the pulp.
– Microorganisms may penetrate deeper causing an
acute exacerbation manifested by clinical flare-up.
– Microorganisms may cause reaction in the periapical
tissue by means of their metabolic products.
Chronic inflammation due to deep dental caries
involving the pulp appears radiolucent on intraoral Fig. 4.4 Radiograph showing mandibular first molar with extensive
periapical radiograph (IOPA) as seen in Figure 4.4. caries involving the pulp (Courtesy of Dr Chetan Shah)
A B C D E
Figs 4.5A to E Diagrammatic representation of sequel of dental caries: (A) Caries in enamel and dentin; (B) Deep caries causing pulpitis;
(C) Widening of the periodontal ligament space; (D) Periapical granuloma or abscess; (E) Necrotic pulp and periapical abscess
54 Short Textbook of Endodontics
the pulp. There is widening of the PDL space. Persistent – Calcific metamorphosis progresses from coronal part
inflammation causes necrosis of the pulp. Less virulent of the tooth to the apical canal.
microorganisms may result in formation of chronic An alternative sequela to trauma may be idiopathic
abscess. Low grade irritation can result in the formation internal resorption.
of periapical granuloma or cyst. • Repair and regeneration: When inflammatory and
immune reactions are effective, the foreign material
Immune Reactions may be neutralized and removed, initiating repair and
• Humoral and cellular pulpal immune response occurs regeneration.
to invading microorganisms. • There is formation of reactionary (tertiary) dentin, when
• Immunoglobulins such as IgG, IgM and IgA have been no odontoblasts are killed.
found within the odontoblasts of carious dentin. • There is formation of reparative (tertiary) dentin, when
• The three antigen-presenting cell types of pulp include: odontoblasts are killed.
– Macrophages However, normally organized pulp may not reform.
– Dendritic cells Pulp polyp is considered as a chronic inflammation
– B-lymphocytes. in which injury and repair are going on at the same time.
Macrophages express type II major histocompatibility Pulp polyp contains epithelial cells from oral mucosa, large
complex (MHC) molecules on stimulation of bacteria or lymphocytes and also fibrous tissue.
cytokines. Figure 4.6 shows a photograph of pulp polyp in a primary
Dendritic cells form network around blood vessels second molar.
within the pulp and the odontoblast layer and constantly Lymphocytes represent cells of inflammation.
express MHC molecules without provocation. Fibrous tissue represents an attempt to ‘wall off’ the
B-lymphocytes secrete antibodies during specific diseased tissue, i.e. repair.
immune response and express MHC molecules. A mind-map to remember all points of reaction of pulp
Initially, antibodies accumulate in the odontoblast to dental caries (Fig. 4.7).
layer. But as the lesion progresses, they may be found in
dentinal tubules. HOW DOES THE PULP REACT TO DENTAL
• The first cells to encounter an antigen diffusing along the
PROCEDURES?
dentinal tubules are the odontoblasts. The odontoblasts
are stationary and do not directly participate in the Flow chart 4.2 shows different diagnostic and dental
activation of T-cells, but may have a role in activating treatment procedures.
dendritic cells.
• Calcification and internal resorption:
Formation of pulp stones and calcific metamorphosis
has been found to occur in response to caries in chronic
long standing cases.
Calcific metamorphosis
– A pulpal response to traumatic injury characterized
by deposition of hard tissue within the root canal
space is called calcific metamorphosis.
– Calcific metamorphosis commonly occurs in the
anterior teeth that get affected by trauma.
– A tooth with calcific metamorphosis appears darker
in hue than the adjacent teeth and has dark yellow
color due to greater thickness of dentin.
– There is reduction in size of both the coronal and
radicular pulp spaces, sometimes resulting in partial
or total obliteration of pulp canal when seen on
radiograph. PDL space is normal and lamina dura Fig. 4.6 Photograph showing pulp polyp in a primary second molar
is intact. (Courtesy of Dr CR Suvarna)
The Pulpal Reactions to Caries and Dental Procedures 55
Fig. 4.13 Reaction of pulp to drying of tooth Fig. 4.14 Reaction of pulp to acid-etching of dentin
It is recommended that cavity floors be dried with cotton If the open dentinal tubules are left unsealed, the
pellets and short blasts of air rather than harsh chemicals. irritants can diffuse into the pulp and may intensify and
In deep cavities, air blast can cause lots of discomfort to the prolong the severity of pulpal reactions.
patient. Cotton pellets should be used. In superficial cavities, diameter of dentinal tubules is
Also, the tooth must be kept moist during preparation narrow and density of peripheral dentin is low, so etching
and while drying the cavity preparation, care must be taken of dentin followed by adequate sealing with restorative resin
just to remove extra moisture from the operative field and will not cause any detrimental effects on pulp.
not remove dentin’s natural moisture (desiccation). In case of deep cavities or presence of exposure,
phosphoric acid etching can be detrimental.
How does the Pulp React to Cavity Also, in cases where phosphoric acid etching is done
Cleansing and Sterilization? and bacteria are also present, severe pulpal inflammation
Certain caustic chemicals such as hydrogen peroxide, and necrosis tends to occur.
sodium hypochlorite, calcium hydroxide, etc. were used Due to such effects with total etch systems, self-etching
in the past for cavity disinfection to get rid of residual systems have become popular these days which eliminate
microbial contamination of the cavity preparation. But these etching with phosphoric acid. They do not remove the
chemicals may be potentially toxic to the pulp and so they smear layer but this smear layer is incorporated within the
are not used these days. restoration. But the only drawback of self-etch system is that
When dentin is exposed, there is outward flow of it may form a relatively poor bond due to weaker acidity of
dentinal fluid, so the inward flow of any noxious agents is acidic primers of self-etch system than total etch system.
minimized. As a result, the irritation from residual microbial
contamination in dentinal tubules is reduced. How does the Pulp React to Cementation
How Does the Pulp React to Acid of Crown or Bridge?
Etching of Enamel and Dentin? When cementation of crowns, inlays or bridges is done on
When dentin is cut, smear layer is produced containing vital teeth, hydraulic forces may be exerted on the pulp as
fragments of microscopic mineral crystals and organic cement compresses the fluid in dentinal tubules.
matrix. Smear layer blocks the orifices of dentinal tubules • Gentle and careful cementation must be done in case
and reduces the permeability of dentin. Etching of dentin of vital teeth
with phosphoric acid removes the smear layer and causes • Vents are provided in the casting that allow the cement
demineralization of surface layer of collagen (Fig. 4.14). to escape and facilitate seating.
60 Short Textbook of Endodontics
suppresses nerve excitability in the pulp. It adapts well to as the corrosion products accumulate between restoration
dentin and inhibits bacterial growth on cavity walls. and the cavity walls.
Zinc oxide eugenol is suitable as temporary filling but
not long-term restoration as it has been found to leak over Restorative Resins
a period of time.
Placement of resin restoration is technique sensitive.
Zinc Phosphate Cement Improper technique can result in faulty bond to tooth
structure causing dentin hypersensitivity, recurrent disease
The phosphoric acid liquid phase may be harmful to the and pulpal inflammation or necrosis.
pulp. But studies have shown that it is relatively safe. Zinc Etching with phosphoric acid dissolves the highly
phosphate cement has been used as base beneath amalgam mineralized peritubular dentin leaving free collagen fibrils
restorations for years. and opening dentinal tubules. The resin in the form of
Zinc phosphate is also well-tolerated by pulp when used bonding agent has to infiltrate the exposed collagen mesh
as a luting agent. and seal the open dentinal tubules. If it does not do so then
there is nanoleakage.
Glass Ionomer Cement Pulpal irritation from resin placement can be
due to irritants such as unpolymerized monomer
When glass ionomer cement is used as liner in deep cavities and polymerization shrinkage. The components of
with RDT of 0.5–0.25 µm, it results in deposition of tertiary unpolymerized monomer may leach directly into pulp
dentin but at a slower rate than calcium hydroxide. in case of deep cavities and cause chemical irritation.
When glass ionomer cement is placed over exposed Polymerization shrinkage of composites induce internal
healthy pulp, there is severe pulpal inflammation or necrosis stresses on dentin and create voids causing microleakage.
similar to that for calcium hydroxide. This can be minimized by incremental placement and
When glass ionomer cement is used as luting agent in vital curing of composites and starting the restoration with
teeth, for sometime after luting, there is postcementation flowable resins.
sensitivity which subsides over a period of time.
BIBLIOGRAPHY
Silver Amalgam 1. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis:
Mosby; 2006.pp.514-40.
Amalgam cannot be placed directly over the cavity 2. Grossman L, Oliet S, Del Rio C. Endodontic Practice, 11th edn.
preparation, it has to be placed over a liner/base such as Varghese publication, 1991.pp.59-65.
3. Ingle, Bakland Endodontics, 5th edn. BC Decker-Elsevier; 2002.
zinc phosphate cement to protect the pulp. pp.95-6.
During setting, amalgam shrinks, which results in micro 4. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics 6, 6th edn.
leakage. But over a period of time, marginal seal improves BC Decker Inc, Hamilton; 2008.pp.468-87.
5
CHAPTER
This chapter describes in detail the various diseases of the dental pulp and
the periradicular tissues and their possible causes.
You must know
• What are the Possible Causes of Diseases of Dental Pulp?
• How does the Pulp React to Different Direct and Indirect Stimuli and how is the Response
unique?
• How do we Classify the Diseases of Dental Pulp?
• What are the Different Features of the Diseases of the Dental Pulp?
• What are the Causes of Diseases of the Periradicular Tissues?
• How do we Classify the Diseases of Periradicular Tissues?
• What are the Different Features of the Diseases of Periradicular Tissues of Endodontic Origin?
• What is the Pathogenesis of Primary Apical Periodontitis?
WHAT ARE THE POSSIBLE CAUSES OF DISEASES layer. The affected layer is the area which has
OF DENTAL PULP? been demineralized by acids produced by
bacteria in the infected surface layer.
Causes of Diseases of the Dental Pulp - Reaction of dental pulp to dental caries has been
The various causes of diseases of the dental pulp are listed explained in Chapter 4: The Pulpal Reactions to
in Flow chart 4.1 ‘Noxious stimuli affecting dental pulp/ Caries and Dental Procedures.
Causes of diseases of dental pulp’, in the previous chapter. – Bacterial toxins before direct invasion: The pulp
They will be discussed in detail here. becomes inflamed from irritation by preceding
bacterial toxins long before the bacteria reach the
Microbial/Bacterial Causes pulp to actually infect it.
• Fractured crown: Microorganisms can invade the pulp
Coronal Ingress following injury to tooth (Trauma)
• Caries: Coronal caries is the most common means of – Complete fracture: Accidental fracture generally does
ingress for infecting bacteria and/or their toxins into not devitalize the pulp at that instant. But untreated
the dental pulp coronal fracture results in infection by oral bacteria
– Direct microbial invasion: gaining ready access to the pulp. Most commonly
- There are various portals of entry of micro affected teeth are maxillary anterior teeth. Various
organisms into the pulp. These have been dental traumatic injuries and their management
explained in detail in Chapter 6: Endodontic have been discussed in detail in Chapter 24:
Microbiology Management of Dental Traumatic Injuries.
- Active carious lesion is composed of an outer – Incomplete fracture: Incomplete fracture of the crown
infected layer and a deeper (underlying) affected (infraction) causes entry of bacteria into the pulp.
Diseases of the Pulp and the Periradicular Tissues 63
Pulp infection and associated pulpal inflammation – Periodontal pocket: It may extend to and surround
depends on the extent of fracture (whether complete the root apex. Such retrogenic infection is less
or incomplete) extending into pulp chamber or only common. Periodontal lesion causing Endodontic
through enamel. If it extends into pulp chamber, lesion is explained in Chapter 25: Endodontic-
pulpitis develops. If only through enamel, pulp is Periodontal Inter-relationships.
merely hypersensitive to cold and mastication. – Periodontal abscess: Retrogenic pulp infection
• Nonfracture trauma: It was found by Grossman that the accompanying or immediately following an acute
pulp canal infection can occur from trauma even without periodontal abscess, may be sometimes the cause
fracture of teeth. of unexplained pulp necrosis.
• Anomalous tract: Anomalous tooth development of – Hematogenic blood borne microorganisms colonizing
tooth crown and the root can be a cause of bacterial in the pulp: (Anachoresis) It refers to colonization or
invasion into the pulp. fixation of blood-borne microorganisms in the pulp.
– Dens invaginatus: Most commonly found in There is no enough evidence to explain the invasion
maxillary lateral incisors. It can range from a slight of pulp by bacteria through blood. Systemic transient
lingual pit in the cingulum area to a frank anomalous bacteremia may explain the unusual number of
tract apparent visually or radiographically. infected pulp canals following impact injury or
- Coronal dens in dente may involve all layers of fracture.
enamel organ into the dental papilla. In such
cases, pulp may be exposed and thus opens to Physical
bacterial invasion, inflammation and necrosis.
There may be early development of periradicular Mechanical
lesions.
- In radicular dens, there is a fold in HERS into • Traumatic Injury to Teeth (Acute trauma)
developing tooth, producing enamel and dentin – Traumatic injury may directly or indirectly affect the
there. dental pulp.
– Dens evaginatus: It has a tract to the pulp at its – Trauma to teeth can occur in case of accidents,
point of attachment. Found usually in mandibular sports-related injury (Contact sports) or blow to
premolars. the tooth. Various dental traumatic injuries, their
– Radicular lingual groove or palatogingival groove: effects on the pulp and their management have been
It is found primarily in maxillary lateral incisor. discussed in Chapter 24: Management of Dental
The defect starts in the region of the cingulum and Traumatic Injuries.
proceeds apically and frequently towards the distal - Coronal fracture: Most pulp death following
portion of the tooth for various distances along the coronal fracture is due to bacterial invasion
surface of the root. Due to the nature of the groove, it following the accident.
is thought that the cementum formation is disturbed - Radicular fracture: Accidental fracture of the root
or even absent—No cementum, no attachment. disrupts the pulp vascular supply and the injured
In case of long groove, palatal abscess that forms coronal pulp can lose vitality. The apical radicular
extends to the apex. pulp tissue may remain vital.
- Vascular stasis: In case of severe impact injury,
Radicular Ingress the tooth may lose pulp vitality immediately. The
• Caries: pulp vessels get severed at the apical foramen
– Root caries is bacterial source of pulpal irritation causing ischemic infarction. Another response of
- Less frequent occurrence than coronal caries pulp to trauma is formation of irritation dentin.
- Cervical root caries occurs as a common sequel - Luxation: Extrusive luxation, lateral luxation and
to gingival recession intrusion result in pulp death nearly always. Pulp
- Interproximal radicular caries may follow recovery may occur in case of immature young
periodontal procedures if meticulous oral permanent tooth with wide, open apices.
hygiene is not maintained. - Avulsion: Pulp necrosis occurs as a consequence
• Retrogenic infection: Pulp may become infected through of total avulsion of tooth.
apical foramen or lateral accessory canals associated • Wasting diseases of teeth/noncarious destruction/
with chronic periodontal pocket. diseases of teeth/pathologic wear from attrition,
64 Short Textbook of Endodontics
Iatral (Iatrogenic)
• Cavity preparation
– Heat of preparation: Heat generated during cavity
preparation can cause pulp damage if adequate
water coolant is not used.
Diseases of the Pulp and the Periradicular Tissues 65
Four basic factors in rotary instrumentation fractures. Patient gets relief when the cusp of
that cause temperature rise in the pulp, given by the tooth finally fractures or the crown fractures
Swerdlow and Stanley, include: horizontally.
- Force applied by operator – Force of cementing: The tremendous hydraulic force
- Size, shape and condition of cutting tool exerted during cementation of an inlay or full crown
- Revolutions per minute (RPM) in case of a vital tooth would drive the liquid towards
- Duration of actual cutting time the pulp causing pain while cementing.
Lower speeds produce less thermal elevation – Heat of polishing: Already discussed before in the
than high speeds. thermal causes.
– Depth of preparation: Deeper cavity preparations • Orthodontic movement: Use of mechanical separators
cause more extensive pulpal inflammation. for rapid separation of teeth or rapid orthodontic tooth
– Dehydration: Excessive drying (desiccation) of movement can cause changes in the pulp. Also, some
the exposed dentin during cavity preparation can of the methods employed for removal of orthodontic
contribute to pulp inflammation. brackets after treatment have the potential to injure the
– Pulp horn extensions and pulp exposure: The close pulp.
proximity of the pulp to the floor of the cavity • Periodontal curettage: During the periodontal curettage
preparation can expose the high pulp horns. of a lesion that entirely extends around the apex of the
Slow speed carbide burs can be used in areas of root, the pulp vessels may be severed and the pulp may
deep cavity preparation to avoid any traumatic get devitalized.
mechanical exposure of the pulp. If possible, a layer • Electrosurgery: Inadvertent contact with metallic
of solid dentin (nonleathery) is allowed to remain as restorations during electrosurgery procedure may
pulp cover. Also, it should be noted that use of air- severely endanger the pulp and the periodontal
water coolant is important in the areas where dentin structures.
is thinned and the pulp approached to prevent any • Laser burn: Higher intensity laser radiation can cause
pulpal damage. damage to the pulp.
– Pin insertion: Earlier the pins that were used to • Periradicular curettage: During the periradicular
support amalgam restorations or as a framework curettage of an extensive bony lesion, the devitalization
for building up badly broken down teeth for full of the pulps of adjacent teeth has been found to occur.
coverage restorations, were found to cause pulp • Intubation for general anesthesia: If an inflexible
inflammation and pulpal death. In some cases, pins endotracheal tube is used during general anesthesia,
were inadvertently inserted directly into pulp or so heavy retraction against the mandibular incisors can
close to that they acted as severe irritant. Such pins cause their luxation.
are no longer used with the advent of dentin bonding
agents and adhesives. Chemical Causes
• Restoration • Erosion caused due to acidity: Acidity (hydrogen ion
– Insertion: After the insertion of gold foil or silver concentration) causes erosion of enamel on labial or
amalgam, severe hypersensitivity and pulpalgia facial surface of teeth that eventually gets the dental pulp
may occur related to force of insertion or expansion closer to irritating agents present in plaque and foods.
of amalgam after insertion. Mild to severe • Restorative materials:
hypersensitivity is found to occur after insertion of – Acid etching of dentin with phosphoric acid: Acid
composite restoration, especially when total-etch etchants that contain phosphoric acid used for total
technique using phosphoric acid is used or other etch technique of composite bonding are known
causes such as over-drying of dentin, over-etching, to cause irritation of the pulp especially when
faulty technique, moisture contamination, etc.) The prolonged dentinal etching is done opening up the
use of self-etch bonding agents has been found to dentinal tubules which are not completely occluded
reduce the postoperative sensitivity to a great extent. by application of bonding agent over the etched
– Fracture: Complete or incomplete fracture of surface.
posterior teeth have been found to occur after – C h e m i ca l i r r i t at i o n o f pu l p o c c u r s f ro m
placement of silver amalgam or soft gold inlays or unpolymerized monomer
foil. Patient may have complaint of hypersensitivity – Cavity liners, bases: Since the cavity liners and
or pulpalgia in case of undetected incomplete bases are applied directly on dentin, they should be
66 Short Textbook of Endodontics
Idiopathic
• Aging: Regressive changes occur in the pulp tissue, such
as decrease in number and size of cells and increase in
the number of collagen fibers. There is deposition of
secondary and tertiary dentin and pulp recedes with
advancing age.
• Resorption (internal and external): Various changes
that can occur in case of pathologic tooth resorption
have been explained in Chapter 30 Pathologic Tooth
Resorption.
• Systemic diseases such as sickle cell anemia, herpes
zoster infection, etc.
In case of sickle cell anemia, microcirculation of pulp
is found to be affected resulting in pulp death.
In herpes zoster infection, it is found that the virus
may infect the pulp vasculature leading to infarction and II. Baume classified pulpal diseases based on clinical
pulp death. symptoms as follows:
III. Seltzer and Bender classified pulpal diseases according In reversible pulpitis, peripheral A delta fiber stimulation
to histologic findings: occurs.
WHAT ARE THE DIFFERENT FEATURES OF Diagnosis: It is based on signs and symptoms and clinical
diagnostic tests.
THE DISEASES OF THE DENTAL PULP?
• Clinical signs and symptoms such as sharp pain which
Features of Pulp Inflammation (Pulpitis) is momentary (few seconds) that generally disappears
on removal of stimulus such as cold, sweet or sour may
Reversible Pulpitis point towards reversible pulpitis.
• Diagnostic test such as cold thermal test can help locate
Definition: and diagnose the involved tooth.
• “Reversible pulpitis is a mild to moderate inflammatory • Radiographs generally show normal periodontal
condition of the pulp caused by noxious stimuli in which ligament status. Caries or deep restoration may be
the pulp is capable of returning to the uninflamed state evident.
following removal of stimuli.” (Grossman’s Endodontic
Practice, 11th edition, p.65) Histopathologic findings:
• Disruption of odontoblast layer
Etiology: Various etiologic factors include: (c2d2e2s2t2) • Dilated blood vessels
• caries • Extravasated edema fluid
• defective restorations • Acute or chronic inflammatory cells
• exposed dentin
• excessive dehydration of dentin caused by stream of Treatment:
compressed air or with alcohol or chloroform • Prevention of reversible pulpitis by:
• chemical stimulus from irritation caused by silicate or – Prevention of caries
self-cure acrylic resin – Early detection of caries and restoration
• recent dental treatment – Pulp protection base under restoration for deep
• Decreased threshold stimulation for A-delta nerve fibers cavities
• Maxillary sinus disease causing generalized transient – Placing well-sealed restorations, to avoid marginal
hyperemia of pulp of maxillary posterior teeth leakage
• trauma caused from a blow or due to disturbed occlusion – Proper contouring of restorations.
or occlusal prematurity (high point) – Adequate water coolants while cavity preparation or
• thermal shock due to cavity preparation without while polishing metallic restorations.
adequate water coolant or using a dull bur or keeping the • Palliative treatment includes:
bur in contact with the tooth for long time or excessive – Remove the restoration and replace it with a sedative
heat produced during polishing of restoration. cement such as Zinc oxide Eugenol.
68 Short Textbook of Endodontics
If pain persists or worsens, then extirpation of pulp Diagnosis: Based on clinical findings and diagnostic tests
is advised. and radiographic examination:
– Reduce occlusal trauma if present. • On inspection, deep cavity or secondary caries at the
margins of restoration may be seen or grayish leathery
Irreversible Pulpitis layer over the exposed pulp and surrounding dentin may
be visible.
Definition: “Irreversible pulpitis is a persistent inflammatory • Probing over this superficial layer may not be painful.
condition of the pulp, symptomatic or asymptomatic, Deeper layers might elicit pain on probing.
in which the pain persists for several minutes to hours, • Thermal tests elicit pain persisting even after removal
lingering even after the removal of the stimulus”. (Grossman’s of stimulus.
Endodontic Practice, 11th Edition, p.67) • Radiographic appearance of periradicular bone may
show minimal changes such as thickening of periodontal
Etiology: ligament.
• Most common cause is bacteria affecting the pulp from • Calcification in the form of pulp stones or calcification
caries. in canal may be evident on radiograph.
• Untreated reversible pulpitis progresses to irreversible
pulpitis Histopathology:
• Can have any of the other physical or chemical causes. • Chronic and acute inflammatory changes in the pulp
• Thermal stimulation of A-delta nerve fibers causing are evident.
lingering pain and stimulation of unmyelinated C-fibers • Congestion of postcapillary venules
causing spontaneous, dull aching pain. • Phagocytosis of PMN leukocytes
• Large open cavity (Figure 5.2 shows photograph of pulp • Pulp polyp should be distinguished from gingival polyp
polyp in deciduous molar with large open cavity). – Pulp polyp is more sensitive than gingival polyp
– Raise the polyp and trace its stalk to find its origin.
Signs and symptoms: Pulp polyp originates from pulp chamber
• Usually asymptomatic • On probing, pulp polyp bleeds profusely due to rich
• Sometimes if food bolus gets lodged in the open cavity network of blood vessels within it.
causing pressure, discomfort may be felt by the patient • While performing diagnostic tests such as thermal and
• May bleed profusely if gets traumatized. electric pulp tests, more current and more cold stimulus
may be required to elicit pulp response.
Diagnosis:
Histopathology:
• Generally occurs in teeth of children and young adults
• Stratified squamous epithelium covering the surface of
• On inspection, fleshy, reddish pulpal mass filling most
pulp polyp is seen.
of the pulp chamber or cavity is seen.
• Chronic inflammatory changes in pulp
• Such polypoid tissue sometimes may extend beyond the
• Granulation tissue containing PMN neutrophils,
confines of the tooth causing discomfort while biting.
lymphocytes and plasma cells is evident.
Treatment:
• Periodontal curette or spoon excavator is used to
remove the hyperplastic pulpal mass completely to the
level of orifices.
• Bleeding is controlled.
• Endodontic treatment is completed.
Internal Resorption
Definition: “Internal resorption is an idiopathic slow or
fast progressive resorptive process occurring in the dentin
of the pulp chamber or root canals of teeth”. (Grossman’s
Endodontic Practice, 11th Edition, p. 71)
Figure 5.3 shows diagrammatic representation of the
internal resorption. The etiology, clinical features, diagnosis
and different types of internal root resorption are discussed
in detail in Chapter 30 Pathologic Tooth Resorption.
Fig. 5.3 Internal resorption Fig. 5.4 Free, attached and embedded pulp stones
Diseases of the Pulp and the Periradicular Tissues 71
– It has been found that such degenerated pulp from i. No response to cold test
the root canal has leathery fiber appearance. ii. No response to electric pulp test
Atrophic and fibrous degeneration do not have a iii. Response may be elicited to prolonged
clinical diagnosis. application of heat due to remnants of pulpal
fluid or gases expanding and extending into
Features of Pulp Necrosis periapical region.
– Radiographic changes :
• Definition: Pulp necrosis is defined as: “Partial or i. Large carious lesion may be seen.
total death of pulp following inflammation or a ii. Pulp stones in pulp chamber or some evidence
traumatic injury in which pulp gets destroyed before an of calcification in root canal may be seen.
inflammatory reaction takes place”. iii. Thickening of PDL space.
• Etiology: • Histopathology: Pulp cavity shows necrotic pulp tissue,
– Untreated symptomatic or asymptomatic irreversible cellular debris and microorganisms.
pulpitis progresses to necrosis. • Treatment: Endodontic treatment.
– Trauma: Basically, injury to pulp by noxious stimuli
such as bacterial, traumatic or chemical irritation
WHAT ARE THE CAUSES OF DISEASES
leads to necrosis of pulp.
• Types: OF THE PERIRADICULAR TISSUES?
• Diagnosis:
– History of severe pain lasting from few minutes to
few hours, followed by cessation of pain completely.
– In some patients, there can be slow death of pulp
without any symptoms
– Tooth may become symptomatic to percussion as
the infection extends into PDL space
– Tooth may exhibit hypersensitivity to heat or
sometimes even to the warmth of oral cavity. Such
pain is often relieved by application of cold. This
helps in localization of necrotic tooth.
– Diagnostic tests such as thermal and electric pulp
tests:
72 Short Textbook of Endodontics
C. Ingle has given the following classification: (see flow Fig. 5.5 Intraoral periapical radiograph showing normal
chart on next page) periradicular tissues
Diseases of the Pulp and the Periradicular Tissues 73
Fig. 5.15 CBCT image showing tooth with a pathology likely to be Fig. 5.16 Radiograph showing condensing osteitis in relation
radicular cyst (Courtesy of Dr Mansi Shah, Dentoview: Advanced to mandibular second molar tooth (Courtesy of Dr Mansi Shah,
dental imaging center) Dentoview: Advanced dental imaging center)
BIBLIOGRAPHY
1. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis:
Mosby; 2006.pp.40-58, 541-79.
2. Grossman L, Oliet S, Del Rio C. Endodontic Practice, 11th edn.
Varghese publication; 1991.pp.59-101.
3. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics, 6th edn.
BC Decker Inc, Hamilton; 2008.pp.468-487, 494-513.
4. Ingle, Bakland Endodontics, 5th edn. BC Decker, Elsevier; 2002.
pp.95-149.
6
CHAPTER
Endodontic Microbiology
This chapter tells you about the role of microorganisms in the pathogenesis of Endodontic disease and
the techniques for identification and control of Endodontic infections.
You must know
• What is the Basis of Focal Infection Theory and Why is it Totally Rejected Today?
• What are the Pathways or Portals of Entry of Microorganisms in the Pulp?
• What is the Microbial Flora of Root Canal?
• What are the Types of Endodontic Infections?
• What is the Role of Microbial Virulence and Host Response in the Pathogenesis of Disease?
• What are the Methods for Detection, Identification and Examination of Microbes?
• What is the Biofilm and what is its Significance in Endodontics?
WHAT IS THE BASIS OF FOCAL INFECTION • In 1910, William Hunter, in a lecture on role of sepsis
THEORY AND WHY IS IT TOTALLY and antisepsis in medicine, condemned the practice
REJECTED TODAY? of dentistry and stated that nonvital pulps and
Endodontically treated teeth were the cause of many
Supporters of this theory believed that pulpless and chronic illnesses. This presentation inadvertently
Endodontically treated teeth may leak bacteria or toxins affected the practice of root canal therapy and
or both into the body, causing illnesses such as arthritis, unwarranted extraction of nonvital and Endodontically
intestinal disorders, anemias and other diseases of the treated teeth continued for approximately 20 years.
various systems of the body. Other details of the focal infection theory are given
With the expansion of this theory, millions of teeth were in Chapter 8 Rationale of Endodontic Therapy.
needlessly extracted to cure various chronic illnesses.
Rejection of Focal Infection Theory
Origin of Focal Infection Theory
In 1930, an editorial published in dental cosmos, rejected the
• In 1890, WD Miller proposed that pulpal and periapical focal infection theory and called for a return of constructive
disease was associated with the presence of bacteria. rather than destructive dental treatment rationale.
• In 1904, Billings defined ‘focus of infection’ as Numerous studies were conducted to cure chronic
‘circumscribed area of tissue infected with pathogenic illness, but in nearly all cases, the disease returned and
organisms’ and described the positive correlation the patient now faced the additional difficulty of living
between oral disease and bacterial endocarditis. with mutilated dentitions.
• In 1904, Rosenow, a student of Billings, described the
‘theory of focal infection’ which stated that localized Conclusion
or generalized infection is caused by bacteria traveling On the basis of various clinical and scientific studies, both
through the bloodstream from a distant focus of medical and dental professions concluded that there is
infection. no relationship between Endodontically treated teeth or
84 Short Textbook of Endodontics
nonvital pulps and the degenerative diseases implicated DRAPE—Dentinal tubules, Restorations, Anachoresis,
in the theory of focal infection. Periodontal tissues, Exposure of pulp).
Also, many epidemiologic and biologic studies dem
onstrated that Endodontic therapy is safe and results in WHAT IS THE MICROBIAL FLORA
saving the teeth without endangering systemic health. OF ROOT CANAL?
Colonization is the establishment of microbes in a host
WHAT ARE THE PATHWAYS OR PORTALS OF when biochemical and physical conditions are adequate for
ENTRY OF MICROORGANISMS IN THE PULP? growth. Normal microbial flora is the result of permanent
Microorganisms can enter the pulp through different colonization of microbes in a symbiotic relationship that
pathways as listed in Figure 6.1. (Remember the Mnemonic: produces beneficial results.
Fig. 6.2 Diagram showing dental caries: (a) Dental caries; Fig. 6.4 Diagram showing pulp exposure due to trauma: (a) PDL
(b) Infected pulp; (c) Periapical pathology widening; (b) Traumatic exposure of pulp; (c) Angle fracture of
maxillary central incisor
A B
Figs 6.3A and B Diagram showing exposed dentinal tubules as Fig. 6.5 Diagram showing pulp exposure during restorative
pathway to pulp: (A) Normal tooth; (B) (a) Attrition; (b) Exposed procedures. Pulp exposure in a mesially inclined mandibular molar
dentinal tubules; (c) Abrasion during tooth preparation for receiving fixed partial denture indicated
by arrow
86 Short Textbook of Endodontics
Fig. 6.6 Diagram showing pathways of pulp through periodontal Fig. 6.8 Radiograph showing recurrent caries at the margins of
tissues: (a) Lateral canal; (b) Furcation canal; (c) Periodontal pocket; restoration causing pulpal involvement and periradicular infection
(d) Accessory canals; (e) Apical foramen in mandibular first molar (Courtesy of Dr Chetan Shah)
Flow chart 6.2 Different bacteria in an infected root canal II. Secondary root canal infections may be caused by
microorganisms that were not present during primary
infections but introduced during treatment between
appointments or after Endodontic treatment.
Commonly found microorganisms in case of
secondary Endodontic infections include:
– Enterococcus
– Staphylococcus
– Streptococcus
– Actinomyces
– Pseudomonas
– Candida sp.
– Propionibacterium
Improper coronal seal causing leakage has been
implicated as an important cause of post-treatment
apical periodontitis.
Flow chart 6.3 Classification according to Gram stain technique III. Persistent root canal infections may be caused by
bacteria present within the canal at the time of
obturation that resist filling procedures and materials
to survive even in changed environment maintaining
the periradicular inflammation. This is most important
cause of Endodontic failure.
Enterococcus faecalis is predominant microbe
in canals undergoing retreatment in cases of failed
Endodontic therapy and canals with persistent
infections. Also Streptococcus faecalis, Actinomyces sp.,
Candida sp. may be found in such cases.
• It can persist in spite of poor nutrient environment in in combination with natural resistance to various
Endodontically treated teeth. antimicrobial agents.
• It survives even in the presence of root canal irrigant such Figure 6.10 shows a mind-map to remember all the
as sodium hypochlorite and intracanal medicament microbial flora of root canal and types of Endodontic
such as calcium hydroxide. infections and Figure 6.11 summarizes all points of
• It tends to invade and metabolize fluid within dentinal microbiology of infected root canal.
tubules and adheres to collagen in the presence of
human serum. WHAT IS THE ROLE OF MICROBIAL
• It endures prolonged periods of starvation and utilizes VIRULENCE AND HOST RESPONSE IN
tissue fluid from periodontal ligament. THE PATHOGENESIS OF DISEASE?
• It is known to convert into a Viable But Non-Cultivable
state (VBNC) The ability of microorganisms to produce a disease is called
• It can survive in adverse conditions such as low pH, high pathogenicity.
salinity and high temperatures. The degree of pathogenicity caused by microbes is
• It can acquire gene-coding antibiotic resistance referred to as virulence.
The pathogenic response includes damage caused WHAT ARE THE METHODS FOR DETECTION,
by the host in response to the microbes. Host’s response IDENTIFICATION AND EXAMINATION OF
includes: MICROBES FROM A ROOT CANAL?
• Nonspecific inflammatory reaction Flow chart 6.6 lists the methods for detection, identification
• Specific immunologic reaction and examination of microbes.
The pathogenic responses are associated with:
a. Microorganisms (Bacterial virulence factors given in Culture Methods
Figure 6.12)
Technique
b. Associated host responses (Flow chart 6.5).
• Isolate the tooth with rubber dam.
Bacterial Virulence Factors • Remove the dressing from root canal of previous visit.
• Insert a sterile absorbent point into the canal and wipe
(Remember the short sentence: PLEASE Care For— the canal to remove any intracanal medicament.
Polyamines, Lipopolysaccharides, Enzymes, Ammonia, • Take a fresh, sterile absorbent point till the apex or
Short chain fatty acids, Extracellular vesicles, Capsule, slightly beyond to absorb as much periapical exudates
Fimbriae (Fig. 6.12). and microorganisms from the root canal as possible.
Fig. 6.11 Mind-map to remember all points of microbiology of infected root canal
90 Short Textbook of Endodontics
Let the absorbent point remain there for at least one collected in oxygen free, anaport vial and transported to
minute. any anaerobic culturing depot for examination.
• The absorbent point is removed with the sterilized cotton
pliers and is put into the culture medium. Advantages
• The sample is sent for laboratory examination. Gram- • It allows identification of a great variety of microbial
staining demonstrates which type of microorganisms species in a sample.
predominate. • Helps in determination of antimicrobial susceptibility
• Culturing anaerobic microorganisms from samples for appropriate treatment.
obtained from root canal and periapical tissue require
special equipment and temperature controlled, oxygen- Disadvantages
free medium.
Using an aseptic technique, sterile needle of Luer Lok • They have low sensitivity and specificity
syringe is inserted into periradicular space. Aspirate is • May give false-negative results
Endodontic Microbiology 91
Flow chart 6.5 Host response to the microbes Flow chart 6.6 Methods for detection, identification and
examination of microbes
Fig. 6.13 A mind-map to remember all points of methods for detection, identification and examination of microbes
Endodontic Microbiology 93
The sessile microorganisms protected in biofilms are Polymeric Substances (EPS) that anchors bacterial
more than 1000 times resistant to antimicrobial agents as cell to substrate. About 85% by volume of Biofilm
the same organisms in planktonic form. is matrix material and 15% is cells. A fresh biofilm
The phenotype of biofilm bacteria is distinct from that consists of polysaccharides, proteins, nucleic acids
of planktonic bacteria. and salts embedded in extracellular matrix. Matured
Bacterial cells within the biofilm have altered phenotypic biofilm structure and composition varies according to
properties that protect them from: environmental conditions such as: growth conditions,
i. Antimicrobials nutritional availability, etc. A viable, fully hydrated
ii. Environmental stresses mature biofilm appears as tower or mushroom shaped
iii. Bacteriophages structure adherent to the substrate. The primitive
iv. Phagocytic amoebae circulatory system in the biofilm is water channels that
Since biofilms are resistant to both host defense intersect the structure of biofilm and form connections
mechanisms and antibiotic therapy, they are responsible between microcolonies that facilitate exchange of
for most chronic infections and recalcitrant infections in materials between bacterial cells and bulk fluid. This
human beings. is important in coordinating functions of biofilm
• Common biofilms found in oral cavity are protective community.
in nature and essential for maintenance of oral
• Development of Biofilm: Biofilms tend to form when
health as they inhibit the adherence of pathogenic
there is flow of fluid, microorganisms and a solid surface.
microorganisms through colonization resistance.
Figure 6.15 shows the schematic representation of stages
But any environmental change favoring colonization
of biofilm formation.
by pathogenic bacteria causing ecological shift and
decline in host defense mechanism due to disease will Stage 1: Formation of conditioning layer: The inorganic and
cause harmless commensals to become opportunistic organic molecules get adsorbed to the solid surface to form
pathogens. Type and availability of nutrients and oxygen conditioning layer, e.g. Saliva pellicle is the conditioning
tension determine the nature of bacteria associated with layer on tooth during dental plaque formation.
a biofilm. All common oral diseases—Dental caries,
Stage 2: Adhesion of microbial cells to the conditioning layer.
Gingivitis, Periodontitis, apical periodontitis are biofilm-
mediated diseases. Stage 3: Bacterial growth and biofilm expansion. Micro
colonies are formed. Two microbial interactions that occur
• Ultrastructure of Biofilm (Fig 6.14): Microcolonies or at cellular level include:
cell clusters formed by surface adherent bacterial cells, i. Coadhesion which is recognition between suspended
surrounded by Glycocalyx matrix made of Extracellular cell and cell already attached to substratum (Fig. 6.16B)
Fig. 6.14 Schematic representation of ultrastructure of mature biofilm (N-Nutrients; M-Metabolic products; S-Signal molecules)
94 Short Textbook of Endodontics
Stage 2 Planktonic bacterial cell attachment Stage 3 Bacterial growth and biofilm expansion
ii. Coaggregation in which genetically distinct cells in in primary and post-treatment Endodontic infections.
suspension recognize each other and clump together Microbes persist in anatomical complexities such as
(Fig. 6.16A). isthmus, deltas and in apical portion of root canal system
The detachment of microcolonies to detach from biofilm and may also invade beyond the apical foramen.
community can be in two forms:
i. Erosion: Continual detachment of single cells and small Types of Biofilm
portions of biofilm. 1. Intracanal Microbial Biofilms:
ii. Sloughing: Rapid, massive loss of biofilm. – Formed on root canal dentine of Endodontically
Detachment shapes morphological characteristics of infected tooth
biofilm and serves as active dispersive mechanism (Seeding – Intracanal bacterial biofilm was documented in
dispersal). Detached cells that have acquired resistance detail by Nair in 1987
traits from parent biofilm community, can be a source for – Composed of loose collection and biofilm structure
persistent infection. of cocci, rods and filamentous bacteria
Biofilm in Endodontics: When there is infection in – Monolayer and/or multilayered bacterial biofilms
the root canal, its nutritional and environmental status is adhere to the dentinal wall of root canal
altered. It becomes more anaerobic. Nutritional level is – Intracanal biofilm has extracellular matrix
depleted making it a tough ecological niche for surviving material of bacterial origin interspersed with cell
microorganisms. This favors biofilm formation both aggregates
Endodontic Microbiology 95
3. Periapical Bofilms:
– Isolated biofilms found in periapical area of
Endodontically infected teeth
– Actinomyces and P. propionicum have been found
in asymptomatic periapical lesions refractory to
B Endodontic treatment.
– Actinomyces has yellow granular appearance (called
sulfur granules). Periapical biofilm structure is
Figs 6.16A and B Schematic representation of coaggregation and
co-adhesion between different bacterial cells forming biofilm granular containing central mass of intertwined
branching bacterial filaments held together by
extracellular matrix with peripheral radiating clubs.
– Phagocytes cannot engulf bacteria in matrix
– E. faecalis can develop biofilms according to enclosed biofilm structure.
prevailing environmental and nutrient conditions:
i. In nutrient-rich environment (aerobic and 4. Biomaterial Centered Infection (BCI):
anaerobic): E. faecalis is found to produce – Bacteria adheres to an artificial biomaterial surface
typical biofilm structures with characteristic to form biofilm.
surface aggregates of bacterial cells and water – When biomaterials are present in close proximity to
channels. Viable bacterial cells present on the host immune system, it increases susceptibility
biofilm surface. for BCI.
ii. In nutrient-deprived environment (aerobic – It is a major complication associated with prosthesis
and anaerobic): Irregular growth of adherent and implant-related infections. In Endodontics, it
cell clumps. Dead bacterial cells and pockets can form on root canal obturating materials and can
of viable bacterial cells found. be intraradicular or extraradicular depending on
whether the obturation material is within the canal
Formation or extruded beyond apex.
– Microbes associated with BCI: Coagulase negative
Stage 1: E. faecalis adhere and form microcolonies on the Staphylococcus, S. aureus, enterococci, streptococci,
root canal dentine surface. P. aeruginosa and fungi found from infected
Stage 2: Bacterial-mediated dissolution of the mineral biomaterial surfaces. E. faecalis, S. sanguinis,
fraction from dentin substrate was induced. S. intermedius, etc. have been isolated from biofilms
related to obturation material. Gram-positive
Stage 3: Mineralization or calcification of E. faecalis biofilm facultative anaerobes can colonize and form
due to localised increase in calcium and phosphate ions. extracellular matrix on GP points. Serum plays a role
Coaggregation interactions between E. faecalis in biofilm formation.
and F. nucleatum occur and contribute to Endodontic – Bacterial adherence to biomaterial surface is
infections. described in following phases:
96 Short Textbook of Endodontics
- Phase 1: Transport of bacteria to biomaterial (by means of Asepsis). For the disruption of biofilm
surface and reduction of microbial load, combination
- Phase 2: Initial, nonspecific adhesion phase of mechanical instrumentation and various root
- Phase 3: Specific, adhesion phase. canal irrigants and disinfectants such as Sodium
– Clinical Significance: Apical periodontitis is hypochlorite, Chlorhexidine digluconate, MTAD,
essentially a biofilm-induced disese. The structure calcium hydroxide, etc. are being used. Also other
of Biofilm and the resident microorganisms is methods such as use of Endoactivator, Ultrasonics,
such that it is resistant to antimicrobial agents Lasers, Ozone therapy, etc. are being employed to
such as antibiotics, disinfectants or germicides. eradicate biofilms and achieve complete root canal
Endodontic treatment should focus on elimination disinfection. These have been discussed in detail in
of microbes that colonize infected root canal Chapter 15: Disinfection of the Root Canal System.
system (by means of Antisepsis) and prevent Mind-maps to remember all points of biofilm are given
introduction of new microorganisms in the canal in Figures 6.17 and 6.18.
Endodontic Microbiology 97
This chapter describes a systematic and methodical approach towards making an accurate
diagnosis. It includes the various odontogenic and nonodontogenic causes of orofacial pain,
which sometimes presents a true diagnostic and therapeutic challenge to the clinician. The
chapter also explains in detail the various diagnostic aids in Endodontics.
You must know
• What is Diagnosis and how to be a Successful Diagnostician?
• What are the Steps to be followed to Arrive at an Accurate Diagnosis?
Flow chart 7.1 Simplified chart showing steps to make an accurate diagnosis
Past Dental History • Progression of pain: Whether the pain has reduced,
• Information regarding the last dental visit. become worse or same (unchanged).
• Whether there has been any recent dental treatment. • Aggravating factors: Factors that precipitate or aggravate
This may help to localize a particular problem. pain help in directing objective tests.
The lack of aggravating factors indicates that the pain
Pain History is nonodontogenic.
• Relieving factors: Factors that alleviate pain.
This involves both careful listening and astute questioning. – Whether the pain is responsive to specific medication
The clinician has to determine the source of pain. – Moderate intensity pain but unresponsive to anti-
Odontogenic inflammatory drugs suggests a noninflammatory
Source of pain origin.
Nonodontogenic • Associated factors: Such as swelling, discoloration and
Well-localized numbness.
• Location
Diffuse Orofacial Pain/Dental Pain
Superficial
Location Definition of Pain
Deep
– Easily localized superficial pain: May be Cutaneous “Pain is defined as an unpleasant sensory and emotional
or Neurogenic origin. experience associated with actual or potential tissue damage
– Deep pain, that may be localized when provoked: or described in terms of such damage.” (International
May be Musculoskeletal in origin Association of Study of Pain (IASP).
– Deep diffuse pain: May be Somatic, Visceral or By far ‘pain’ is the most important/only factor that
Musculoskeletal. provokes the individuals to seek dental care.
– Superficial and spreading pain: May be Neurogenic
rather than a Cutaneous source. Classification
• Intensity: Can be determined using Verbal Analog Scale
which means on a scale of 0–10, with 0 being no pain • Classification of dental pain:
and 10 being the worst pain, how does the patient rate
the pain.
Sudden
• Onset of pain
Gradual
This helps to determine the etiology.
Unchanging pain that has been present over a protracted
period is highly suggestive of a nonodontogenic source.
Whether the pain is – Spontaneous
– Elicited with hot/cold/chewing
• Duration of pain – Momentary
– Lingering
• Whether the pain is Continuous or Intermittent
• Nature of pain – Dull ache (May be muscular)
– Sharp shooting
– Shock like, Burning
(May be neurogenic)
– Throbbing, pulsatile
(May be vascular)
102 Short Textbook of Endodontics
Referred Pain
“The perception of pain in one part of the body that is
distant from the actual source of pain is known as Referred
pain”.
• Pain of nonodontogenic origin can refer pain to teeth.
Also teeth may refer pain to other teeth as well as to
other anatomic areas of the head and neck.
• It is provoked by intense stimulation of pulpal C-fibers
that cause intense, slow, dull pain.
• Referred pain always radiates to Ipsilateral side of the
tooth involved.
• Rarely, anterior teeth refer pain; Posterior teeth may refer
pain to Opposite arch, to Periauricular area, or rarely to
anterior teeth.
• Dental pain of myofascial origin may or may not be Trigeminal neuralgia: It can be diagnosed based on:
associated with pulpal or periapical pathosis. • There is intense, sharp, shooting pain on stimulation of
• Dental pain of myofascial origin can be diagnosed based trigger zones and is unilateral.
on following: • Slight pressure on trigger zones results in severe pain.
– Local anesthetic block will not resolve symptoms but This pain usually subsides within few minutes until
if local anesthetic is administered into trigger point, triggered again.
it will resolve symptoms • Trigger zones for trigeminal neuralgia may be intraoral
– Lack of symptoms after pulp testing and may be triggered by chewing.
– Palpation of masticatory muscles will elicit pain • Administration of local anesthetic in the area of trigger
– Percussion of teeth will not elicit pain. zones may resolve the symptoms and can be misleading.
• Sharp, shooting pain in the absence of dental etiology
Neurovascular Pain vs Pulpal Pain should alert the clinician to include trigeminal neuralgia
Neurovascular pain presents mainly as headache with in differential diagnosis.
accompanying toothache perceived secondary to headache.
Primary headache is of three types: Cardiac Pain
1. Migraine • Cardiac pain may be referred to left side of mandible.
2. Tension-type headache • Cardiac pain can be spontaneous and diffuse similar to
3. Cluster headache pulpal pain.
• Migraine presents as unilateral, pulsatile, moderate • Diagnostic features:
to severely intense headache which is likely to be – Associated medical history pointing to cardiac
aggravated with routine physical activity. Patients may problem
experience nausea or vomiting or photophobia. – Cardiac pain will not get aggravated by local
• Tension-type headache does not mimic toothache. provocation of teeth
• Pain of neurovascular origin presenting primarily as – Administration of local anesthetic will not reduce
toothache is more likely to be cluster headache. the pain.
Cluster headaches occur in episodes lasting for 15
minutes to 2 hours. There may be 1–8 such episodes in a day. Psychogenic Pain
Presents as unilateral, excruciating orbital, supra-orbital or • Patient will have complaint of toothache, yet lacks a
temporal pain. Other symptoms may be ipsilateral nasal physical cause.
congestion, rhinorrhea, lacrimation. • Psychogenic toothache is very rare.
Elimination of pain following 10-minute inhalation of • Diagnosis of psychogenic toothache only by ruling out
100% oxygen is diagnostic for cluster headache. all other potential diagnoses.
Referred pain is felt in maxillary anterior or premolar • Psychogenic pain may be precipitated by severe
teeth. psychologic stress. It may not follow any anatomic
distribution. Pain may be felt in multiple teeth.
Important Diagnostic Features A Mind-map to remember all points of case history
taking (Fig. 7.5).
• Neurovascular pain occurs in episodes with complete
remission between episodes whereas pulpal pain will STEP 2: CLINICAL EXAMINATION
be continuous or may present as discomfort between
any aggravating episodes. General
• Local anesthetic administration is unpredictable. • The clinician must observe the patient as he/she walks
• Administration of oxygen to rule out cluster headache into the operatory by his/her gesture and body language.
can make definitive diagnosis. • Obtain and record the patient’s vital signs: (TPR BP)
Temperature, pulse rate, respiratory rate, blood pressure.
Neuropathic Pain vs Pulpal Pain Temperature
Neuropathic pain arises from abnormalities in neural • An elevated body temperature (fever) indicates total
structures. body reaction to inflammatory disease.
Diagnosis and Diagnostic Aids in Endodontics 105
• Normal body temperature is 98.6oF. A temperature above No dental treatment should be done if blood pressure
this but below 100oF indicates localized disease. readings of diastolic pressure is over 100 mm Hg on that
Localized disease can be treated: day. Consent and consultation with the patient’s physician
• By removing the cause (Root canal opening and cleaning needs to be done.
and disinfection) and/or Sometimes, elevated blood pressure is caused only by
• Incision and drainage (I and D). stress and anxiety of the moment and must be dealt with
Pulse rate: Normal pulse rate is 60–100 beats per minute. reassurance or pretreatment sedation if required.
Stress and anxiety can cause elevated pulse rate. • Other abnormalities such as breathlessness, altered gait,
unusual body movements must be recorded.
Respiratory rate: Normal respiratory rate is 16–18 breaths • Cancer screening of soft tissues: Extraoral and intraoral
per minute. This rate also gets elevated due to stress and soft tissues must be evaluated for any kind of lump,
anxiety. swelling, white spots or scaly patches or sore spots
Blood pressure: Normal BP is 120/80 mm Hg for persons for early detection of any precancerous or cancerous
under 60 years of age and 130/90 mm Hg for persons over lesion.
age of 60 years.
106 Short Textbook of Endodontics
Extraoral Examination
• Patient is examined for any signs of facial asymmetry.
Figure 7.6 shows photograph of a patient having
facial asymmetry due to extraoral swelling on left
side.
• Any localized swelling, change in color, bruises, or similar
signs of disease, trauma or previous treatment should be
looked for.
• Inspection and palpation of painful and/or enlarged
lymph nodes.
• Any opening of sinus tracts through skin of face.
• Extent and manner of jaw opening.
• Temporomandibular joint examination—any tender
ness, clicking, irregular movement, etc.
Fig. 7.6 Facial asymmetry due to extraoral swelling on left side
Intraoral Examination (Courtesy of Dr Manoj Ramugade)
Visual and Tactile Inspection
• For careful inspection, there should be good light and
dry conditions and good mouth mirror and probe/
explorer.
• Magnification in the form of Loupes and dental
operating microscope allow the clinician to visualize
what cannot be observed with naked eye.
• Inspection of:
Figure 7.7 shows photograph of a patient with
changes in color, contour and consistency of all
maxillary teeth due to hypoplasia.
The clinician should avoid “tunnel vision”–that is
examining only the area of chief complaint of the patient.
Palpation
• Manual digital palpation, i.e. palpation with fingers of
soft and hard tissues around the tooth in question should
be done.
Figure 7.8 shows photograph demonstrating manual Fig. 7.8 Photograph showing manual digital palpation in the
digital palpation in the mucobuccal fold of maxillary left mucobuccal fold of maxillary left canine (Courtesy of Mr Amar,
canine. Dr Dabholkar’s clinic)
Diagnosis and Diagnostic Aids in Endodontics 107
Fig. 7.10 Percussion of upper right canine with butt end of mirror Fig. 7.11 Back ends of mirror handles to check mobility of tooth
handle (Courtesy of Mr Amar, Dr Dabholkar’s clinic) (Courtesy of Mr Amar, Dr Dabholkar’s clinic)
Mobility and Depressibility • The periodontal probe is “stepped” around the long-axis
of the tooth, progressing in 1 mm increments.
Mobility of teeth indicates either loss of periodontal Diagnostic criteria given by Harrington to determine
attachment due to trauma, parafunctional habits, whether the periodontal defect is of Endodontic or
periodontal disease, root fracture or it could be extension periodontal origin:
of infection from pulp to PDL space. Once the initiating – If periodontal probe Sinks abruptly into an isolated
factors are eliminated or treated, the mobility reverses to periodontal defect, it could be due to Vertical root
normal. fracture.
Lateral movement of tooth in socket is called mobility. – If periodontal probe Steps down into a periodontal
Vertical movement of tooth in socket is called defect and a similar finding occurs on the
depressibility. contralateral side of the arch, it could be due to a
This test is performed using back ends of two mirror generalized periodontal disease.
handles—one on buccal aspect of tooth and one on lingual • Furcation defect or bone loss can occur secondary to
aspect of tooth as shown in Figure 7.11. periodontal or pulpal disease. Furcation canals can be
a portal of exit for necrotic pulp tissue byproducts.
Clinical furcation probing and radiographic
assessment of the furcation defect is done. Grades of
furcation involvement:
Periodontal Examination
• Periodontal probing is an essential part of the diagnostic
process.
• Each tooth is evaluated in atleast three locations—
mesial, middle and distal aspect, on both buccal and
the lingual surfaces.
• Periodontal defects could be a sign of either an Figure 7.12 shows mind-map to remember all points of
Endodontic or a periodontal problem. clinical examination.
Diagnosis and Diagnostic Aids in Endodontics 109
Therapeutic Uses
For treatment radiographs, technique is even more critical.
With rubber dam in place, visibility is reduced,
Fig. 7.13 Radiograph showing deep occlusal caries in mandibular sometimes it may be difficult to expose working radiographs.
first molar approaching the pulp During Endodontic treatment, radiographs are useful
for:
• For determination of working length (Fig. 7.15)
• Examining the position of an instrument within the root
to localize hard-to-find and negotiate root canals
• To determine position and adaptation of master cone
• To evaluate obturation
• During root end surgery, to localize the apex and
following root end surgery, to confirm before suturing
that all tooth fragments and excess filling material have
been removed.
Prognostic Uses
• To evaluate the outcome of treatment:
– Success: Radiographic evidence of resolution of
lesion and re-establishment of normal periapical
Fig. 7.14 Radiograph showing deep carious lesion in the crown and
structures.
periapical radiolucency in relation to mesial root of mandibular first – Failure: Persistence or emergence of radiographic
molar signs of disease.
Diagnosis and Diagnostic Aids in Endodontics 111
LIMITATIONS OR DRAWBACKS OF
RADIOGRAPHS
• Radiographs provide two-dimensional image of three- RADIATION SAFETY
dimensional object. Additional radiographs at different
angulations have to be taken to obtain the desired ALARA principle: As Low As Reasonably Achievable.
information. As per this principle, ‘No matter how small the radiation
• Radiograph is only an adjunctive tool and can be dose, there still may be some deleterious effects’.
misleading. Radiographs alone cannot be used for It is best to keep the ionizing radiation to a minimum
diagnosis. Radiograph alone can lead to misinterpretation for protection of both the patient and the dental staff.
112 Short Textbook of Endodontics
Principles of ALARA
Clinical Aspect
Technical Aspect
• Select fast (i.e. sensitive) speed film, either Ultraspeed
(U) or E.
• Use dental units with 70 kvp or higher kilovoltage
since lower kvp causes increased patient’s skin dose.
Optimally 90 kvp should be used.
• Units operating at 70 kvp must have filtration equivalent Conventional Radiography
of 2.5 mm of aluminum to eliminate the low-energy
X-rays before patient absorbs them. • Requires use of conventional standard films and
• Collimation with lead diaphragm restricts the X-ray processing chemicals.
beam size so that it does not exceed 2.75 inches (7 cm) • Requires dark room procedures for processing of
at the patient’s skin surface. radiographs.
• Open-ended, circular, or rectangular lead-lined • Increased radiation exposure.
cylinders are called position-indicating devices (PIDs) • Perfectly exposed and perfectly processed radiograph
are recommended as they direct the beam to target and is required for it to have good diagnostic quality.
collimate the X-ray beam reducing patient exposure. Proper dark room organization, film handling and
PIDs should be at least 12–16 inches long. Pointed cones adherence to time and temperature method of film
should not be used as they produce increased amount processing play an important role in producing good
of scatter radiation. images.
It should be understood that digital detectors are
much more sensitive to radiation as compared to Xeroradiography
conventional direct exposure emulsion X-ray films.
So, digital detectors require lower radiation exposure. • Xeroradiograph can be exposed by conventional
With digital radiography there is 50–90% reduction X-ray machine using less than usual radiation. It
in exposure as compared to conventional film-based is automatically processed and delivered as a dry,
radiography. laminated permanent film in 25 seconds.
Thus, digital radiography plays an important role in • Xeroradiography produces images of sharper clarity and
radiation safety. finer detail.
Diagnosis and Diagnostic Aids in Endodontics 113
Fig. 7.16 Photograph showing the monitor and the electronic sensor for digital radiography
Paralleling Technique
• Size of pulp chamber is observed. Resorption of apical lamina dura and widening of PDL space
• Abnormal pulp calcification in response to caries or may occur as an early or limited response to infection in
trauma may be seen. root canal system or may be due to increased tooth mobility
• Calcification may be diffuse or localized. occurring as a result of orthodontic movement, periodontal
• Sometimes, pulp chamber may appear to be obliterated. disease or parafunctional habits.
• Small areas of resorption, invaginated enamel, dens
in dente, etc. these findings sometimes may be Alveolar Bone
overlooked. • Density of bone in periapical area: Increased density of
bone in response to infection may be seen in periapical
Root area referred to as condensing osteitis.
• Bone loss: Around the roots should be noted.
Pulp Canal/Root Canal
• Number of canals, additional roots and canals, Periapical Pathology
accessory, lateral canals should be looked for, while
interpreting the radiograph for Endodontic diagnosis Periapical granuloma, cyst, abscess may be evident on the
and treatment. radiograph.
Two or more radiographs at different angulations can
be viewed and compared and then the findings can be Anatomic Structures
interpreted.
• Shape of the canals, curvatures should be noted. Sometimes normal anatomic structures may be misinter
• Degenerative localized or diffuse calcifications in the preted as pathoses. For example, mental foramen, incisive
radicular pulp. foramen will appear as radiolucencies in the periradicular
• Pulp obliteration. area. They can be differentiated from pathologic conditions
by exposures at different angulations and by pulp-testing
Root Fracture procedures. Other anatomic radiolucencies include:
Maxillary sinus, nutrient canals, nasal fossa, submandibular
Fracture of root may not be evident on radiograph but may fossa, etc.
result in reparative processes that become recognizable in
later radiographs. Differential Diagnosis Based on Radiographic
Findings can be Interpreted
Root Resorption: External or Internal
Based on radiographic evaluation, following conditions may
Internal resorption causes replacement of dentin by a soft be suspected or diagnosed (As given in Ingle):
tissue with resorbing cells. This may result in a balloon- • Hypercementosis: Cementum deposition around the
shaped lesion starting from the radicular pulp seen as round roots clearly seen on radiographs. It may occur in
or ovoid radiolucent area observed on the radiograph. response to pulpal inflammation without infection in
Internal pulp wall appears to be destroyed whereas apical part of canal.
cementum and periodontium seem to be unaffected in – Pulpitis would require Endodontic treatment.
initial cases of internal resorption. – Hypercementosis persists even after Endodontic
treatment.
Periapical Area • Condensing apical osteitis: It represents altered bone
structure associated with chronic pulpitis and resolves
Integrity of Lamina Dura following adequate therapy.
Determining the integrity of lamina dura has a diagnostic • Idiopathic osteosclerosis: It may be closely located to
value when recent radiograph can be compared with apex of a vital tooth.
previous one. – Does not require Endodontic treatment.
Also, integrity or lack of integrity of lamina dura in • Marginal periodontitis: Its radiographic features are
relation to health of the pulp is to be determined. similar to apical periodontitis. If it is associated with
118 Short Textbook of Endodontics
necrotic and infected pulp, combined Endodontic- Applications of CBCT in Endodontics include:
periodontal treatment is recommended. • Localization of canals (Fig. 7.21)
• Root fractures: It may be seen as a variant of apical • Assessment of root fractures (Figs 7.22A to C)
periodontitis. When pulp canal space and the fracture • Evaluate the angulation of root (Fig. 7.23) and root
slit are infected, it results in periodontitis, where the resorption (Figs 7.24 and 7.25)
fracture communicates with periodontal space. • Periradicular pathologies in all planes can be
In vertical root fracture (VRF), the whole length of root evaluated. Example periapical or radicular cyst (Figs
may be affected, producing a diffuse halo of radiolucent 7.26A and B).
bone around the root.
• Osteomyelitis: Sequestration of bone and apparently STEP 3: DIAGNOSTIC TESTS
normal bone structures are seen between areas of bone
destruction. Goals of Diagnostic Tests
• Inflammatory paradental cyst: A rare entity, occurring
exclusively in mandibular molar area. Ingle has stated 2 goals of diagnostic tests (Fig. 7.27).
• Lateral periodontal cyst: A developmental cyst occurring Diagnostic tests are important adjunctive tools in the
in premolar area of mandible and sometimes in maxilla. decision-making process that leads to both pulpal and
It may be mistaken for apical periodontitis. periapical diagnoses. Do not rely on a single diagnostic test
• Nonodontogenic incisive canal developmental cyst: result. If at least one more test gives similar findings, then
Located centrally between maxillary incisors and may the appropriate treatment is recommended.
be mistaken for apical periodontitis if projected over the
apex. Various Pulp Tests
• Simple bone cyst: Traumatic bone cyst.
• Osseous/cemental dysplasia: Occurring in lower Pulp tests determine the pathological status of pulp.
anterior region. Teeth are vital, there are no clinical
symptoms. Radiographically can mimic chronic apical Specific Pulp Tests
periodontitis.
• Giant cell granuloma: Large multilocular, radiolucent • Thermal tests:
area. – These tests identify the presence of pulp nerve
• Hyperparathyroidism. tissue that is capable of responding to a change in
• Odontogenic keratocyst. temperature.
• Benign or malignant tumors of jaw. – They may provide information that suggests whether
A mind-map to remember all points of RADIOGRAPHS the pulp is reversibly or irreversibly inflamed or
is given in Figure 7.20. necrotic.
– The preferred temperature for heat test is 65.5oC
Advanced Multiplanar Imaging: Cone Beam (150oF).
– It is important to isolate individual tooth with rubber
Computed Tomography (CBCT) for Endodontics
dam while performing thermal tests to prevent any
It is digital advanced imaging that helps to obtain an image of false positive results from the adjacent teeth.
virtually any plane through a structure that greatly improves – Abnormal response to thermal tests is elicited as:
diagnostic information of its 3-dimensional morphology. It - Lack of response to stimulus-Lingering or
involves section imaging. Axial, coronal and sagittal sections intensified pain sensation after removal of the
can be obtained with less patient exposure as compared to stimulus
conventional CT scans. Cone beam computed tomography - Immediate, excruciating painful sensation as
(CBCT) is a compact, faster and safer version of regular CT. soon as the stimulus is placed upon the tooth.
The buccolingual dimension which cannot be appreciated Figure 7.28 shows heat test being performed using
on radiographs can be clearly visualized on CBCT images. guttapercha stick.
Diagnosis and Diagnostic Aids in Endodontics 119
Fig. 7.21 CBCT image showing MB2 canal in a maxillary first molar Fig. 7.23 CBCT image of a tooth with dilaceration. (Courtesy of Dr
tooth. (Courtesy of Dr Mansi Shah, Dentoview: Advanced Dental Mansi Shah, Dentoview: Advanced Dental Imaging Center)
Imaging Center)
A B C
Figs 7.22A to C CBCT images showing horizontal root fracture of palatal root of maxillary second premolar tooth.
(Courtesy of Dr Mansi Shah, Dentoview: Advanced Dental Imaging Center)
A B
Fig. 7.24 CBCT image showing blunting of apex caused due to Figs 7.25A and B CBCT image showing internal resorption in a
external root resorption. (Courtesy of Dr Mansi Shah, Dentoview: tooth. (Courtesy of Dr Mansi Shah, Dentoview: Advanced Dental
Advanced Dental Imaging Center) Imaging Center)
Diagnosis and Diagnostic Aids in Endodontics 121
A B
Figs 7.26A and B CBCT image of a radicular cyst. (Courtesy of Dr
Mansi Shah, Dentoview: Advanced Dental Imaging Center)
Procedure pulp. It only denotes that some viable nerve fibers are
• Teeth to be evaluated are isolated and dried. present in the pulp that are capable of responding.
• A control tooth (contralateral vital tooth) should be • The use of electric pulp tester in a patient with cardiac
tested first in order to establish a baseline response and pacemaker can interfere with its function. So it is contra-
to help the patient know what a “normal” sensation is. indicated in such patients.
• Dry contact with the tooth does not evoke a response. • It may cause some anxiety in the patient knowing the
The tooth should be coated with a conductive medium instrument passes an electric current through their
to transmit current such as petroleum jelly, water-based teeth.
jelly, toothpaste or prophylactic paste. • False-positive responses can also occur just as in thermal
• Optimal placement of probe tip is on the occlusal 2/3rd tests in adjacent teeth especially those with contacting
of labial or buccal surfaces of teeth or the incisal edges. metal fillings.
• Once the probe tip is in contact with the tooth, the • This test is not reliable in younger teeth with immature
patient is asked to place the finger lightly on the metal apices or in teeth following a traumatic injury.
part of the probe to complete the circuit and initiates • It relies on subjective response by the patient and only
the delivery of electric current to the tooth. measures the neurological status of pulp, not the vitality
• Patient is instructed to remove his/her finger from the in true sense.
probe handle when a warm, tingling sensation is felt.
• The suspected tooth should be tested at least twice to Cohen has given the following accuracy rate results of pulp
confirm the results. tests:
• In case of complete coverage crown, a small metal Cold test → 86%
Endodontic instrument such as files or explorers can Electric test → 81%
be used as bridging instrument, with the tip coated with Heat test → 71%
contact medium and placed on enamel or dentin of the These usual pulp tests provide information only about
tooth being evaluated. The probe tip is then placed on the presence or absence of nerve receptors in the pulp and
the metal of the bridging instrument. not about the pulpal blood supply.
Figure 7.29 shows electric pulp test being performed
using electric pulp tester. Methods to assess pulpal circulation: Assessment of pulpal
circulation is more accurate determinant of pulp vitality as
Limitations compared to thermal tests because it uses methods that are
objective tests that help to differentiate between vital and
• The response to electric pulp testing (EPT) does not necrotic pulp.
reflect the histological health or disease status of the
Pulpal circulation can be assessed with the following
methods:
• Laser Doppler flowmetry
• Pulse oximetry
• Transmitted light-Photoplethysmography
• Infrared thermography
Laser Doppler Flowmetry and Pulse Oximetry are
explained here.
According to the Doppler principle (Law of Light Principle: It employs a light source probe that emits
Frequency Shift) simultaneously two light beams:
• The light beam will be frequency-shifted by moving red 1. One transmits red light (640 nm)
blood cells. 2. Other transmits infrared light (940 nm)
• The light beam will remain unshifted as it passes through • The light passes through the tissue of interest
the static tissue. • A photodetector is placed on the opposite side
This average Doppler frequency shift will measure the of the light source to capture whatever light gets
velocity at which the red blood cells are moving. through
• Oxygenated hemoglobin and deoxygenated
Application of Laser Doppler Flowmetry (LDF) hemoglobin absorb different amounts of red and
in Dentistry infrared light.
Laser Doppler Flowmetry can be used to assess pulpal The machine calculates the difference between the light
blood flow. emitted and the light received to provide the pulse rate and
The initial use of LDF was exclusively for direct soft tissue oxygen concentration in blood.
blood flow measurements. But for dental situations, there
is interference of hard tissues like dentin and enamel. Application in Dentistry
If it is properly conducted:
• It is found to be an accurate, reliable and reproducible Pulse oximetry has been tested and suggested to assess pulp
method to assess pulpal blood flow and check vitality vitality with mixed results. Some studies have found pulse
of tooth pulp. oximetry test to have high accuracy rate while other studies
• It has been shown to work in primary incisors as well showed that it does not have predictive diagnostic value for
• It is very useful in cases of dental trauma diagnosing pulp vitality.
• It can identify “at risk” teeth early after the trauma The technology uses devices that are too cumbersome
• In case of avulsion, it can detect revascularization after and complicated, hence, not feasible for routine dental
a few weeks and well in advance of other traditional practice.
clinical tests.
Drawbacks
• Initial high set-up cost
• Accurate and consistent reading of LDF assessment
requires certain critical steps to be taken
• May not be feasible for routine dental practice.
• Cannot be used if the tooth to be tested cannot be
stabilized.
• Devices used for bite test: Cotton applicators, toothpicks,
Pulse Oximetry orangewood sticks, rubber polishing wheels.
Tooth slooth is specifically designed to perform bite test.
It is a noninvasive and objective way to record the oxygen Figure 7.30 show bite test using cotton roll. Figures 7.31
saturation of blood and pulse rate. and 7.32 show tooth slooth for bite test.
124 Short Textbook of Endodontics
Procedure
Transillumination
• Applications:
– To determine the presence of a crown or root
fracture
– Detection of caries, calculus and soft tissue lesions
– Aid in determination of pulp vitality
• Devices used:
– Specifically designed fiberoptic lights
– High speed handpiece with fiberoptic activated or
Fig. 7.32 Bite test being performed with tooth slooth in place. Tooth other bright point light sources.
slooth should make contact with the cusp tips (Courtesy of Dr CR Figure 7.35 show the fiberoptic light source for
Suvarna) transillumination test as demonstrated in Figure 7.36.
Diagnosis and Diagnostic Aids in Endodontics 125
Anesthetic Test
• When other diagnostic tests have been inconclusive,
then selective anesthesia may be helpful to locate the
offending tooth or the arch and to derive the appropriate
diagnosis.
• Administration of the local anesthesia could be by
infiltration, block or intraosseous injection.
• When the patient is unable to determine which arch Fig. 7.35 The fiberoptic light source for transillumination test
(Courtesy of Dr CR Suvarna)
the pain is coming from then a periodontal ligament
Fig. 7.33 Caries detector dye (Courtesy of Dr CR Suvarna) Fig. 7.36 Demonstrating transillumination test
(Courtesy of Dr CR Suvarna)
126 Short Textbook of Endodontics
PULPAL DIAGNOSIS
Simplified chart that will direct your thinking process to correct clinical diagnosis
Clinical • No spontaneous • Presence of caries, • Sometimes deep caries • Asymptomatic • Symptoms of pain
subjective symptoms exposed dentin, but asymptomatic • No response to electric (spontaneous)
and objective • Respond to pulp recent dental • Intermittent or pulp tests or to cold • No response to
findings tests treatment, defective spontaneous pain stimulation electric pulp tests or
• Symptoms/ restorations • Stimuli causing • May respond to heat cold tests
response to • Stimulation with temperature changes • Multirooted teeth: • May respond to heat
pulp tests are an irritant causes (Especially cold) elicit sometimes roots • Pain on percussion
mild that do not symptoms, but its heightened and may give confusing • Tooth may become
cause distress removal resolves prolonged episodes of symptoms, one root very hypersensitive
• Transient symptoms pain even after removal responds, other does to heat
sensation, of stimulus not
reverses in • Pain may be sharp, or • Tooth may become very
seconds dull, localized or referred hypersensitive to heat
Radiographic • No evidence of • No significant • Minimal changes in • Deep caries • Thickening of PDL
findings resorption, caries radiographic change radiographic appearance • Thickening of PDL space
or pulp exposure of periradicular bone • Pulpal involvement • Periapical radiolucent
• Calcification may • Thickening of PDL lesion
or may not be • Extensive canal
present calcification in response
to pulpal irritation
• Deep restorations, caries,
exposure may be evident
↓ ↓ ↓ ↓ ↓
Diagnosis Indicates normal Indicates reversible Indicates irreversible Partial or complete pulp Pulp necrosis with
pulp pulpitis pulpitis necrosis periapical lesion
Treatment plan No treatment • Requires palliative • Root canal treatment • Root canal treatment • Root canal treatment
treatment according
to cause
• Remove etiologic
factors
PERIAPICAL DIAGNOSIS
Clinical • Very painful • No clinical symptoms • Very painful to biting pressure, percussion • No clinical symptoms
response to • No response to pulp and palpation • No response to pulp vitality
biting pressure or vitality tests • Not respond to any pulp vitality tests tests
percussion • Tooth not sensitive to • Mobility of various degrees may be • Tooth not sensitive to
• May or may not biting pressure, but some present biting pressure but “feels
respond to pulp different sensation may • Swelling may be present in mucobuccal different” upon percussion
vitality tests be felt on percussion fold • Intermittent drainage
↓ ↓ • Febrile, lymph nodes may be tender on through an associated
palpation sinus tract
Radiographic • Widened PDL • Periradicular • Can exhibit anything from a widened PDL • Periradicular radiolucency
findings space but not radiolucency, usually space to a periradicular radiolucency present
periradicular around apical third of
radiolucency. root
↓ ↓ ↓ ↓
Diagnosis Acute periradicular/ Chronic periradicular/ Acute periradicular/apical abscess Chronic periradicular/apical
apical periodontitis apical periodontitis abscess (suppurative)
128 Short Textbook of Endodontics
– Thermistors are found to be consistent in recording • Clinician’s attitude: Clinician must have the attitude of
the surface temperatures of teeth with both vital and considering each and every patient ‘important’ and give
necrotic pulps. his full attention and expertise in treatment.
– Electronic thermography can determine the relative
differences in temperature in both superficial and Diagnosis
deep areas and it can be a useful adjunct to other Some cases may be straight forward, where, the findings
pulp diagnostic tests. clearly point towards the diagnosis. In few cases, a list of
A mind map to remember all point of diagnostic differential diagnosis is made and then based on reasoning
tests is given in Figure 7.37. and clinical judgment, a definitive diagnosis is derived by
exclusion.
STEP 4: ARRIVING AT AN ACCURATE Few cases may present a diagnostic challenge, where an
obvious dental etiology cannot be found. An existing medical
ENDODONTIC DIAGNOSIS
problem or a nonodontogenic cause should be suspected
After thorough questioning, examination and testing, the and looked for and appropriate referral be made to protect
various subjective, objective, clinical testing and radiographic the patient from unnecessary dental treatment.
findings are considered for decision-making process to The pulpal and periapical diagnosis is made based on the
arrive at an accurate diagnosis. findings and appropriate reasoning to determine whether
The clinical judgment for decision-making is influenced the case requires Endodontic treatment or not.
by various factors such as: A simplified chart that directs your thinking towards an
• Knowledge and skills: Developed by education and accurate pulpal and periapical diagnosis to formulate the
training. necessary treatment plan is given on page number 127.
• Clinical experience: With experience of various cases
over a period of time, clinician develops the judgment BIBLIOGRAPHY
to correlate various findings and come to a definite
conclusion in a short time. 1. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis: Mosby,
• Updating information: Keeping abreast with the latest 2006. pp.2-39.
2. Grossman L, Oliet S, Del Rio C. Endodontic Practice, 11th edn.
trends in the field: Varghese publication, 1991. pp.1-18.
– by reading appropriate literature and 3. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics, 6th edn. BC
– Attending continuing education courses Decker Inc, Hamilton, 2008. pp.520-637.
8
CHAPTER
Rationale of Endodontic
Therapy
This chapter tells you about the logic behind doing Endodontic therapy.
You must know
• Which were the Proposed Theories of Spread of Infection that Developed into Modern
Philosophy of Endodontics?
• How do Dental Biologic Tissues React to Noxious Stimuli?
• Why is Inflammatory Response of Pulp Different from other Parts of Body?
• What Tissue Changes Occur during Inflammation?
• What Tissue Changes Occur following Inflammation?
• What is Role of Immunity in Endodontics?
• What are the Zones of Reaction of Periradicular Tissues and What are Endodontic
Implications?
WHICH WERE THE PROPOSED THEORIES OF According to the Focal Infection Theory, the focus of
SPREAD OF INFECTION THAT DEVELOPED INTO infection is often unrecognized, while secondary infections
THE MODERN PHILOSOPHY OF ENDODONTICS? might occur at sites particularly susceptible to such
microbial species or toxins such as gallbladder, kidney, liver,
Focal Infection Theory (FIT): An Obsolete prostate; but most commonly oral tissues.
Concept Now In 1920s, Dr Weston Price presented a research
suggesting that the bacteria entrapped in the dentinal
In 1891, WD Miller published a report, entitled as “Human tubules during Endodontic treatment could leak and lead to
mouth as focus of infection”. He used Robert Koch’s postulates systemic diseases such as arthritis, diseases of kidney, heart,
to establish microbial etiology of infectious diseases. He nervous, gastrointestinal, endocrine and other systems.
concluded that mouth was a focus of infection and that the Dr Price advocated tooth extraction over Endodontic
bacteria in mouth caused various systemic diseases. treatment. It resulted in era of tooth extraction both for
In 1909, Dr William Hunter identified oral sepsis as a treatment of systemic disease and as a prophylactic measure
cause of systemic diseases. Later Billings described the against future illness.
terms focus of infection and focal infection and the term The Focal Infection Theory led to needless extraction of
oral sepsis was replaced by focal infection. millions of Endodontically treated teeth until well-designed
A focus of infection is described as a confined area studies conducted during 1930s demonstrated that this
that contains pathogenic microorganisms, that can occur theory was not valid. Dr Price’s research techniques were
anywhere in the body and usually causes no clinical criticized as they lacked many aspects of modern scientific
manifestations. research, including absence of proper control groups and
A focal infection is a localized or generalized infection induction of excessive doses of bacteria.
caused by the dissemination of microorganisms or toxic In 1940, Reiman and Havens stated that the suggested
products from a focus of infection. focal infection theory has not been proved. The infectious
Rationale of Endodontic Therapy 131
HOW DO THE DENTAL BIOLOGIC TISSUES REACT WHAT ARE THE TISSUE CHANGES THAT
TO NOXIOUS STIMULI? OCCUR DURING INFLAMMATION?
Various noxious stimuli that can affect the dental biologic Inflammation: Basic Concepts
tissues (Bacterial, Physical, Chemical, etc.) and the reaction
of the dental pulp to these stimuli have been explained in • Inflammation is local physiologic reaction of body to an
detail in Chapter 4 ‘The Pulpal Reactions to Caries and irritant or noxious stimulus.
Dental Procedures’. • Object of Inflammation → to Remove the irritant
Such stimuli can result in reversible or irreversible (R2) → to Repair damage to the
changes in the pulp and the periradicular tissues as listed tissue
in Flow chart 8.1. • Type of inflammation Predominant cells
The changes that occur in the pulp and the periradicular – Acute and early stages PMN neutrophils
tissues are mediated by a series of inflammatory and of inflammation
immunological reactions in order to eliminate the irritant – Chronic inflammation Lymphocytes, plasma
and repair any damage, which will be explained in detail in cells, monocytes,
this chapter. macrophages
• Cardinal symptoms of inflammation:
WHY IS THE INFLAMMATORY RESPONSE IN – Pain (dolor)
– Swelling (tumor)
CONNECTIVE TISSUE OF DENTAL PULP
– Redness (rubor)
DIFFERENT FROM OTHER PARTS OF BODY? – Heat (color)
Pulpal inflammatory response is modified due to following – Disturbance of function (Functio lesea).
reasons: In an inflamed pulp, all these symptoms occur, but only
• Pulp is encased within the hard tissues pain and disturbance of function are recognized clinically.
• Pulp has limited space to expand during inflammation In case of acute inflammation of periradicular tissues, all
• Pulp has limited portals of entry the cardinal symptoms may be recognized clinically.
132 Short Textbook of Endodontics
– Both basophils and mast cells contain granules 3. Neuropeptides: Neuropeptides such as Substance P,
and when stimulated, by injury they degranulate Calcitonin-gene related peptide (CGRP) are potent
and release chemical mediators such as histamine vasodilators. Increased production and release of
(vasodilator) and heparin (anticoagulant). They can neuropeptides plays an important role in initiating and
initiate inflammatory allergic responses. propagating the inflammation of the pulp.
4. Cytokines: They are polypeptides produced by many cell
Inflammatory Mediators types that play a role in modulating the function of other
cell types. These include Interleukin-1, Interleukin-8 and
The main biologic function of inflammatory mediators is to tumor necrosis factor (TNF). IL-1 and TNF are produced
cause vasodilatation and increased vascular permeability by activated macrophages. They induce the synthesis
and recruit inflammatory cells, mainly neutrophilic and surface expression of the endothelial adhesion
leukocytes and macrophages from blood circulation to molecules and bring about enhanced leukocyte
the site of tissue injury. The inflammatory reactions are adhesion to endothelial walls. IL-1 has been found
mediated by chemical substances produced by certain cells mainly in periapical pathology and IL-8 is associated
or present in plasma. with acute apical periodontitis. TNF is associated with
chronic apical lesions and root canal exudates. IL-1
Nonspecific Inflammatory Mediators and IL-8 are proinflammatory cytokines and TNF is a
I. Cell derived mediators: chemotactic cytokine.
1. Vasoactive amines such as histamine, serotonin 5. Nitric oxide: Nitric oxide in macrophages act as free
(5-Hydroxytryptamine) radicals, which are cytotoxic to certain microbes and
2. Lysosomal enzymes tumor cells. It increases vascular permeability and
3. Neuropeptides causes inactivation of anti-proteases.
4. Cytokines 6. Eicosanoids such as prostaglandins or leukotrienes
5. Nitric oxide are released through the cyclooxygenase pathway and
6. Eicosanoids. lipooxygenase pathway in response to injury to cells,
which are involved in inflammatory process.
II. Plasma derived mediators
1. Complement system II. Plasma derived mediators:
2. Kinin system 1. Complement system: It consists of 20 component
3. Coagulation and fibrinolytic system. proteins and their cleavage products found in greatest
concentration in plasma. Components of complement
Specific Inflammatory Mediators: Antibodies system such as C3a, C3b, C5a, C5b, C5-C9 are products
of the complement cascade, which can be activated by
I. Cell derived mediators: two pathways: The classic pathway and the alternate
1. Vasoactive amines such as Histamine, Serotonin pathway. The classic pathway is initiated by activation of
(5-Hydroxytryptamine): Histamine is released by mast C1 by multimolecular aggregates of IgG or IgM antibody
cell degranulation in response to variety of stimuli complexed with specific antigen and the alternate
such as physical injury, immune reactions involving pathway is activated by microbial cell components
binding of antibody to mast cell, etc. Histamine (lipopolysaccharide, teichoic acid) and plasmin. C3a
causes dilatation of arterioles and increased vascular and C5a causes vasodilation and increases the vascular
permeability of venules. Serotonin is present in platelets permeability and C5a is a powerful chemotactic agent
and enterochromaffin cells. Its release is stimulated for neutrophils, monocytes, eosinophils and basophils
when platelets aggregate after contact with collagen, and causes increased adhesion of leukocytes to
thrombin, antigen-antibody complexes. It causes endothelium.
increased vascular permeability. 2. Hageman factor activated Kinin and Coagulation system:
2. Lysosomal enzymes: Collagenase can mediate tissue Kallikrien converts kininogen into bradykinin, which in
injury by degrading collagen and other tissue proteins. turn converts plasminogen into plasmin. Kinins cause
Kallikerin released from the lysosomes promotes the increased vascular permeability, vasodilation and
generation of bradykinin. Lysosomal enzymes cause smooth muscle contraction.
increase in vascular permeability and play a role in Coagulation/Clotting system and fibrinolytic
activation of the complement system. system: Its two components: Fibrinopeptides which
134 Short Textbook of Endodontics
increase vascular permeability and are chemotactic for duration of disease, pulp tests, percussion, palpation
leukocytes and thrombin which increases leukocyte and radiographic findings whereas histologic diagnosis
adhesion and fibroblast proliferation. is a morphologic and biologic description of cells and
extracellular matrix of diseased tissues.
Vascular Changes Clinical diagnosis represents provisional diagnosis based
on signs, symptoms and testing results whereas histologic
1. Vasodilatation: Induced by histamine, prostaglandins, diagnosis is a definitive diagnosis of diseased tissue.
nitric oxide. There is no good correlation between clinical symtoms
2. Increased vascular permeability: Vasoactive amines, C3a, and histopathologic findings of pulpitis and apical
C5a, Bradykinin, Leukotrienes, Platelet activation factor periodontitis. For example, a pulp tissue with acute pulpal
play a role in it. It causes increase in concentration of abscess at cellular level may be clinically completely
red cells in small vessels. Increase in viscosity of blood asymptomatic. Also, many teeth with apical periodontitis
causes slower flow of blood. histologically are clinically asymptomatic.
3. Leukocyte accumulation and migration.
Tissue changes that occur in dental biologic tissues Correlation between Radiographic
during inflammation are summarized in Flow chart 8.2.
and Histologic Findings
Correlation between Clinical and Histologic Findings Radiography detects pathologic changes at tissue level,
Clinical diagnosis of inflammatory pulpal or periapical not cellular levels. Even by using very sensitive imaging
disease is mainly based on clinical signs and/or symptoms, systems such as cone beam computed tomography (CBCT),
PMN leukocytes Round cell Macrophages and osteoclasts Fibroblasts and osteoblasts
infiltration and lymphocytes
Microorganisms are found Around central zone, cellular Small round cells, normal bone cells and Toxins are too diluted and mild
destruction caused by toxins osteoclasts could just survive enough to act as stimulant
discharged from central zone is
seen
Infection is present in the In this area, bone cells die due Toxins become diluted Collagen fibers are laid down
center of the lesion. Thus, to toxins, undergo autolysis. So, by fibroblasts which act as wall of
root canal is seat of infection lacunae appear empty defense around zone of irritation.
It also acts as scaffolding, on which
the osteoblasts built new bone in
an irregular fashion
A B
C D
Figs 8.2A to D Enlarged view of the lower left side of panoramic radiograph (OPG); (A) Preoperative view showing large area of
rarefaction in relation to mandibular canine and mandibular second premolar; (B) Postoperative view after doing Endodontic treatment
in mandibular second premolar and Endodontic retreatment in mandibular canine; (C) One-year follow-up view shows resolution of
radiolucency to a great extent; (D) Two-year follow-up view shows further improvement and return of periradicular tissues to the normal
(Courtesy of Dr Ajay Bajaj)
Flow chart 8.5 Lesion formed as per stimulant Access cavity preparation and optimum cleaning
and shaping of root canals eliminates the reservoir of
bacteria or noxious products. Obturation of the well-
cleaned and well-shaped root canal system followed
by good post-Endodontic coronal restoration seals the
tooth against leakage from oral fluids and bacterial
contamination. As a result, the destroyed periapical
bone undergoes repair and the area of rarefaction
that was seen radiographically gradually resolves and
disappears.
Rationale of Endodontic Therapy Figures 8.2A to D show portions of the panoramic
radiographs taken preoperatively, post-treatment, and
• Effective elimination of the reservoir of microorganisms follow-up after one and two years of a case in which
and their toxins from the root canal system by means Endodontic treatment has been successful and has
of: resulted in the repair of periapical bone. The huge area of
– Unobstructed straight-line access to the apical part rarefaction that is seen in preoperative view has resolved
of the root canals. and almost disappeared in the follow-up radiographs
– Thorough instrumentation of root canals combined taken after one and two years respectively.
with irrigation (cleaning and shaping).
• Well cleaned and well-shaped root canal is obturated to BIBLIOGRAPHY
produce a three-dimensional hermetic seal which: 1. AAE Fact Sheet on Focal Infection Theory.
– Prevents entry of microorganisms or fluids from 2. Grossman L, Oliet S, Del Rio C. Endodontic Practice, 11th edn.
root canal to periapical area or vice-versa (apical Varghese publication; 1991.pp.116-25.
leakage). 3. Hargreaves KM, Cohen S. Pathways of Pulp, 10th edn. Mosby
– Seal the remaining irritants in canal, i.e. entombment Elsevier, St Louis, MO; 2011.pp.532-5.
4. Indramohan J, Karthika B, Mohiddin G. Myth of Endodontics in
of residual bacteria.
oral focal infection. Indian Journal of Multidisciplinary Dentistry.
• The Endodontically treated tooth is protected by quality 2011;2(1):380-2.
coronal restoration to prevent bacterial contamination. 5. Rajendran R, Sivopathasundharam B, Shafer’s Textbook of Oral
(coronal leakage). Pathology, 7th edn, Elsevier Publication; 2012.p.512.
9
CHAPTER
This chapter describes thorough evaluation of a patient who has come for dental treatment. It will help
you to make a decision whether to do or not to do root canal treatment in a particular case and guides
you to formulate an effective Endodontic treatment plan to carry out the procedure.
You must know
• How to Evaluate a Case for Treatment?
• What are the Factors to be Considered for Case Selection for Root Canal Treatment?
• What are the Indications and Contraindications of Root Canal Treatment?
• How to Develop an Endodontic Treatment Plan?
• How to Assess Difficulty of an Endodontic Case?
HOW TO EVALUATE A CASE FOR TREATMENT? May or may not need dental management
alterations.
Each case must be evaluated thoroughly before For example, stage I or II hypertension, type II
commencement of treatment. diabetes, allergy, well-controlled asthma.
Proper evaluation of the patient for treatment includes: ASA III: A patient with moderate to severe systemic disease
• Evaluation of medical condition of patient that is not incapacitating but may alter daily
• Psychological evaluation activities, may have significant drug concerns, may
• Dental evaluation. require special patient care.
Would generally require dental management
Evaluation of Medical Condition of Patient alterations.
For example, stage III hypertension, type
Most of the medical conditions do not contraindicate I diabetes, unstable angina pectoris, recent
Endodontic treatment. There are few systemic conditions myocardial infarction, poorly controlled congestive
that can influence the course of treatment and will require heart failure, AIDS, COPD, hemophilia.
specific modifications. So, it is necessary to evaluate the ASA IV: A patient with severe systemic disease that is constant
medical condition of the patient before we plan to do root threat to life; definitely requires dental management
canal treatment (RCT). alterations; best treated in special facility.
Physical status classification for patients given by For example, kidney failure, liver failure,
American Society of Anesthesiologists (ASA): advanced AIDS.
ASA I: Normal, healthy patient. The ASA classification is a useful guide for preoperative
No dental management alterations required. assessment of relative risk involved in treating a patient.
ASA II: A patient with mild systemic disease that does not If the patient has a systemic disease, under certain
interfere with daily activity or who has significant circumstances, consultation with the patient’s physician
health risk factor such as smoking, obesity, etc. may be necessary.
140 Short Textbook of Endodontics
this reason. So, in spite of probability of a favorable – Accessibility of tooth: Endodontic treatment in
Endodontic prognosis, a tooth with poor periodontal the third molars may be difficult due to poor
support will have to be sacrificed. accessibility.
• Esthetic considerations: As an alternative to orthodontic Limited mouth opening, trismus can make
treatment in case of malaligned anterior teeth such accessibility of posterior teeth difficult or even
as proclined teeth, intentional Endodontic treatment impossible.
can be done and the teeth prepared to correct the – Retreatment cases, particularly those presenting with
inclination to receive full coverage esthetic crowns procedural mishaps such as ledges, perforations,
(Smile Designing). etc. will pose a mechanical challenge before the
• Surgical considerations: Cases where re-treatment is clinician.
being considered, one must determine whether non- – Level of anticipated difficulty in a particular case
surgical or combined means for re-treatment would be has to be determined beforehand and the need for
appropriate. referral to a specialist has to be considered if the case
• Anatomic considerations: Extra roots and canals which seems to be beyond the clinician’s ability.
are sometimes not revealed on radiographs will pose Figure 9.1 shows the mind-map to remember all
anatomic challenge before the clinician. Anatomic the local factors to be considered for Endodontic case
variations with respect to position of tooth, shape of selection.
roots and canals, presence of curvatures, calcifications, Grossman gave the four main factors that determine the
etc. should be considered during case selection. decision to do or not to do root canal treatment: (Grossman’s
• Other factors: Endodontic Practice, 11th edn. p.126)
– Ability to isolate the tooth is an important 1. Accessibility of the apical foramen through the root canal
consideration. 2. Restorability of the involved tooth
Fig. 9.1 Mind-map showing local factors for Endodontic case selection
Case Selection and Treatment Planning 143
3. Strategic value of the involved tooth 6. Chronic hyperplastic pulpitis (Pulp polyp) (Figure 9.3
4. General resistance of the patient. shows photograph of mandibular first molar with pulp
All these have been explained previously in this polyp)
chapter. 7. Internal resorption (Pink teeth) (Figures 9.4A and B show
photograph of teeth with internal resorption that have
WHAT ARE THE INDICATIONS turned pink colored)
AND CONTRAINDICATIONS OF 8. Pulp exposure from severe attrition of tooth (Figure 9.5
ROOT CANAL TREATMENT? shows photograph of multiple teeth requiring root canal
treatment due to pulp exposures from severe attrition)
Indications 9. Intentional root canal treatment for restorative or
1. Irreversible pulpitis: – Acute prosthetic procedures
– Chronic 10. Roots with good periodontal support, over which over
2. Acute apical periodontitis denture can be constructed.
3. Pulp necrosis: Necrosis of pulp may cause discoloration 11. In case of Combined Endodontic-Periodontal lesions,
of tooth (Figures 9.2A and B show photograph of in which tooth is salvageable, Endodontic treatment is
discolored nonvital teeth due to trauma) done prior to Periodontal treatment.
4. Chronic apical periodontitis
5. Nonvital tooth with periapical cyst Contraindications
1. Nonrestorable tooth, i.e. a tooth with insufficient sound
tooth structure remaining (or nonrestorable root surface
caries).
Figure 9.6 shows photograph of badly broken down
teeth due to caries that cannot be restored.
Figure 9.7 shows radiograph showing insufficient
sound tooth structure remaining of maxillary first
premolar tooth that seems to be nonrestorable.
2. Vertical root fracture (VRF).
3. Extensive and untreatable internal or external root
resorption.
4. Caries involving floor of pulp chamber.
5. Extensive periodontal disease around the tooth causing
grade III mobility of tooth.
A
B
Figs 9.2A and B Discolored nonvital teeth Fig. 9.3 Mandibular first molar with pulp polyp
(Courtesy of Dr Manoj Ramugade) (Courtesy of Dr Manoj Ramugade)
144 Short Textbook of Endodontics
Fig. 9.5 Multiple teeth requiring root canal treatment due to pulp Fig. 9.8 Radiograph showing extensive periodontal
exposures from severe attrition (Courtesy of Dr Manoj Ramugade) involvement in mandibular teeth
Case Selection and Treatment Planning 145
Figure 9.8 shows radiograph of mandibular teeth – Local anesthesia must be administered.
with extensive periodontal involvement. – Simply debriding the pulp chamber, i.e. performing
6. Extensive destruction of periapical tissues involving pulpotomy is a highly predictable method of
more than one-third the length of the tooth. providing pain relief in emergency cases.
7. Teeth with complex anatomy where proper instrumen – If time permits, complete Endodontic treatment for
tation will not be possible vital teeth can be performed in the same visit (single
8. Endodontic failure cases with complications of previous visit Endodontics). If not, then clinician must stop at
treatment such as untreatable perforations, large non- pulpotomy, restore the tooth with a temporary filling
retrievable posts, canal transportations, ledges, etc. and schedule the next appointment for the patient.
9. Poor accessibility of tooth due to limited mouth – Once the canal is entered, the clinician must
opening which may be due to trauma, scar from surgical remove all pulp tissue from it as it has been found
procedure, oral submucous fibrosis (OSMF), systemic that partial instrumentation (i.e. leaving tissue
conditions, etc. or inaccessible position of tooth in the remnants in the canal) may result in increased
arch. postoperative pain.
10. Nonstrategic tooth. For example, third molars whose • Nonvital Tooth
antagonist is missing and other all teeth are present for – Can present in 3 ways:
proper function. 1. In a chronic nonvital case, tooth would be
absolutely painless.
HOW TO DEVELOP AN ENDODONTIC 2. Such a tooth, sometimes may suddenly become
TREATMENT PLAN? acutely painful due to decreased host defense
mechanism and increase in virulence of bacteria.
After arriving at a definitive diagnosis, treatment is planned. 3. Sometimes, it may be associated with a fluctuant
In a general treatment plan to maintain oral health of swelling.
the patient, Endodontic treatment is included in the phase – Nonvital tooth is a microbiologic challenge. Clinician
II or surgical phase of treatment. But few cases may require needs to reduce the bacterial load in the root canal
an emergency root canal opening (ERCO) as a preliminary system by opening the tooth and debriding it.
treatment for pain management. – Usually there is involvement of periradicular
In case of emergency, to relieve pain: tissues. Clinician needs to promote decompression
1. For single-rooted tooth: Remove entire pulp tissue from of periradicular tissues by instrumentation and
the canal when possible irrigation of the canal.
2. For multirooted tooth: – If fluctuant swelling is present, incision and drainage
a. Pulpotomy—if less time should be performed along with instrumentation.
b. If some time permits, then removal of pulp tissue – Single visit Endodontics is not recommended in
from largest (biggest) canal, after pulpotomy. nonvital teeth because complete eradication of
Once the clinician has done a detailed evaluation of the infection from nonvital tooth may not be possible
case and made a definitive diagnosis and has now decided in a single visit due to increased microbial load.
to perform Endodontic treatment, various factors need to – There is role of intracanal medicament such as
be considered to plan, how to go about carrying out the calcium hydroxide in these cases for antimicrobial
procedure. effect in between visits.
While formulating an Endodontic treatment plan:
(B) Determine whether it is only an Endodontic lesion or
(A) Determine the vitality of tooth:
there is periodontal involvement also:
• Vital Tooth – Clinician needs to classify the case as primary
– Patient presents with severe pain in an acute vital Endodontic or periodontal, secondary involvement
case. Pain is due to: or true combined disease.
- Increased intrapulpal pressure Once the case is clearly classified, appropriate
- Inflammatory mediators such as prostaglandins. therapy as needed can be provided.
146 Short Textbook of Endodontics
Guidelines for Using the AAE Endodontic Case Difficulty Assessment Form
The AAE designed the Endodontic Case Difficulty Assessment Form for use in endodontic curricula. The Assessment Form makes case
selection more efficient, more consistent and easier to document. Dentists may also choose to use the Assessment Form to help with
referral decision making and record keeping.
Conditions listed in this form should be considered potential risk factors that may complicate treatment and adversely affect the
outcome. Levels of difficulty are sets of conditions that may not be controllable by the dentist. Risk factors can influence the ability to
provide care at a consistently predictable level and impact the appropriate provision of care and quality assurance.
The Assessment Form enables a practitioner to assign a level of difficulty to a particular case.
LEVELS OF DIFFICULTY
MINIMAL DIFFICULTY Preoperative condition indicates routine complexity (uncomplicated). These types of cases would exhibit
only those factors listed in the MINIMAL DIFFICULTY category. Achieving a predictable treatment
outcome should be attainable by a competent practitioner with limited experience.
MODERATE DIFFICULTY Preoperative condition is complicated, exhibiting one or more patient or treatment factors listed in the
MODERATE DIFFICULTY category. Achieving a predictable treatment outcome will be challenging for
a competent, experienced practitioner.
HIGH DIFFICULTY Preoperative condition is exceptionally complicated, exhibiting several factors listed in the MODERATE
DIFFICULTY category or at least one in the HIGH DIFFICULTY category. Achieving a predictable
treatment outcome will be challenging for even the most experienced practitioner with an extensive
history of favorable outcomes.
Review your assessment of each case to determine the level of difficulty. If the level of difficulty exceeds your experience and comfort,
you might consider referral to an endodontist.
The contribution of the Canadian Academy of Endodontics and others to the development of this form is gratefully acknowledged.
The AAE Endodontic Case Difficulty Assessment Form is designed to aid the practitioner in determining appropriate case disposition. The American
Association of Endodontists neither expressly nor implicitly warrants any positive results associated with the use of this form. This form may be
reproduced but may not be amended or altered in any way.
© American Association of Endodontists, 211 E. Chicago Ave., Suite 1100, Chicago, IL 60611-2691; Phone: 800/872-3636 or 312/266-7255;
Fax: 866/451-9020 or 312/266-9867;
E-mail: info@aae.org; Web site: www.aae.org
(Reprinted with permission from the American Association of Endodontists)
148 Short Textbook of Endodontics
© 2005, American Association of Endodontists, 211 E. Chicago Ave., Suite 1100, Chicago, IL 60611
Phone: 800/872-3636 (North America) or 312/266-7255; Fax: 866/451-9020 (North America) or 312/266-9867
E-mail: info@aae.org; Web site: www.aae.org
(Reprinted with permission from the American Association of Endodontists)
10
CHAPTER
Principles of Endodontic
Treatment
This chapter explains about the basic principles to be followed for Endodontic treatment which are
similar to any routine surgery with few differences associated with the anatomy of the root canal system.
You must know
• What are the Principles of Endodontic Treatment?
WHAT ARE THE PRINCIPLES OF Let us remember these nine principles with the help of
ENDODONTIC TREATMENT? following sentence:
I T I S IMPORTANT TO DO CLEAN DENTISTRY
Grossman has given the following nine principles of Isolation, Trauma avoidance, Immobilization, Sterili
Endodontic treatment as given in Figure 10.1. zation, Irritation avoidance, Trephination, Debridement,
Chemoprophylaxis, Drainage.
Principle 1: Isolation
The tooth under Endodontic treatment should be isolated to
maintain a safe and aseptic operative technique. Isolation
of tooth can be achieved using cotton rolls and rubber dam.
Use of rubber dam is mandatory during nonsurgical
Endodontic therapy. Figure 10.2 shows schematic
representation of teeth being isolated using rubber dam
and ready for Endodontic procedure.
Rationale
The rubber dam should be used in Endodontics for the
following reasons.
• Patient protection: From possible aspiration or
swallowing of tooth debris, restorative materials,
Endodontic instruments (files), medicaments, irrigating
solutions, etc.
• Dry, clean operating field: Prevents contamination of
root canal system from saliva, blood and other tissue
fluids.
• Retraction: Adjacent soft tissues (tongue, lips, cheek) are
Fig. 10.1 Principles of Endodontic treatment as given by Grossman retracted and protected.
Principles of Endodontic Treatment 151
Fig. 10.2 Schematic representation of teeth being isolated and Fig. 10.3 Rubber dam kit containing rubber dam sheets, rubber
ready for Endodontic procedure dam frame, rubber damp clamp or retainers, rubber dam punch and
rubber dam forceps (Courtesy of Dentsply)
Fig. 10.4 Rubber dam sheet Fig. 10.6 Rubber dam frame
(Courtesy of Mr Amar, Dr Dabholkar’s Clinic) (Courtesy of Mr Amar, Dr Dabholkar’s Clinic)
Fig. 10.5 Commercially available packed rubber dam sheets Fig. 10.7 Rubber dam clamps
(Courtesy of Mr Amar, Dr Dabholkar’s Clinic) (Courtesy of Dr Shivani Bhatt)
Figure 10.7 shows photograph of the rubber dam – To shed the rubber dam off the wings of the clamp
clamps. after the clamp is positioned.
– Wings cause buccal-lingual deflection of dam from • Dental floss.
isolated tooth, allowing increased access. – To check contacts prior to rubber dam application.
– Disadvantage: Wings may sometimes interfere in – To pass the rubber dam material through the
radiographic interpretation. contacts after placement.
• Parts of clamp: A bow and two jaws. • Wedgets stabilizing cord: Small strips of cord wedged into
• Available in 2 sizes: Small and large. interproximal space, help to stabilize the interproximal
area of rubber dam.
Rubber Dam Punch
• Orabase, rubber base adhesive, cavit, periodontal pack:
• To punch sharp, clean holes on rubber dam sheet To control seepage of fluids at the interface of the tooth
according to the tooth to be isolated. Figure 10.8 shows and the rubber dam material.
photograph of rubber dam punch. Recently, disposable, single use, preframed rubber
• If the punch is not centered correctly, a ‘nick’ or jagged dams have been introduced. For example, Instadam and
cut margin is produced resulting in poor seal. HandiDam for quick application of rubber dam without
the use of conventional frame.
Rubber Dam Forceps
• To hold and carry the retainer during placement and
removal. Methods of Rubber Dam Placement
Figure 10.9 shows photograph of rubber dam forcep.
• Ash-style or ivory-style forceps is used Patient is asked to rinse for 30 seconds with an antibacterial
• Ash-style forceps beaks provides a fulcrum point for agent such as 0.12% chlorhexidine gluconate, to reduce the
posterior or anterior rotation of clamp number of microorganisms in mouth prior to rubber dam
• Ivory-style forceps provides projections from engaging placement.
beaks that allow the clinician to exert gingivally directed • Single motion technique: Most efficient dam application
force necessary to direct the clamp beyond the bulk of technique for Endodontics.
contour and into proximal undercuts. It is named so, as the dam, clamp and the frame are
taken to the tooth to be isolated in a single motion.
Adjuncts to Rubber Dam Placement – Position the bow of the selected clamp through the
hole made in rubber dam sheet.
• Plastic or cement instrument: – Place the rubber dam over the wings of the clamp.
– To ‘tuck’ the edges of rubber dam into gingival sulcus – The forceps stretch the clamp to maintain the
to achieve a fluid tight seal. position of the clamp in the dam.
Fig. 10.8 Rubber dam punch Fig. 10.9 Rubber dam forcep
(Courtesy of Mr Amar, Dr Dabholkar’s Clinic) (Courtesy of Mr Amar, Dr Dabholkar’s Clinic)
154 Short Textbook of Endodontics
– Then the rubber dam is attached to the plastic frame, c. The stretched interproximal dam is cut with scissors
thus allowing for the placement of the dam, clamp and dam is removed.
and frame in one motion. d. Inspect and ensure that no interproximal dam has
– Once the clamp is secured on the tooth, a plastic been left in between teeth.
instrument is used to tease the dam under the wings
of the clamp. Problems Encountered in Rubber Dam Placement
– Use dental floss to pass the dam through contacts.
• Double motion technique. • Leakage – Due to error in placement, seepage can
– Punch appropriate size hole on the dam material. occur.
– Then the rubber dam is loosely attached to the four – In patients with excessive salivation, saliva
corners of the frame. may seep even through well-placed rubber
– The selected clamp is placed over the bulk of contour dam.
of the tooth to be isolated. Solution – Meticulous placement of rubber dam.
– The rubber dam is stretched over the clamp. – Premedication with anticholinergic drug to
– Then it is stretched onto all prongs of the frame. reduce saliva.
– Use dental floss to pass the dam through the contacts.
Figure 10.11 shows diagrammatic representation
of rubber dam placement.
• Split dam technique: To isolate anterior teeth without
using rubber dam clamp. It can also be used for tooth
with insufficient structure.
Figure 10.10 shows photograph showing rubber
dam in place for Endodontic treatment in mandibular
first molar and Figure 10.12 shows access opening of
maxillary central incisor with rubber dam in place.
Fig. 10.10 Rubber dam in place for Endodontic treatment in Fig. 10.12 Access opening in maxillary central incisor with rubber
mandibular first molar (Courtesy of Dr Manoj Ramugade) dam in place (Courtesy of Dr Manoj Ramugade)
Principles of Endodontic Treatment 155
• Insufficient tooth structure: There is problem during • Grossman’s statement: “It is not so much what you put
placement of clamp. into a root canal, but what you take out that counts.”
Solution – Use clamps with prongs inclined apically. Although for successful Endodontic treatment, both are
– Consider restorative procedures to build-up important.
the tooth so that the retainer can be placed
properly. Principle 4: Drainage
– Canal projection technique: Allows pre In case of gross infection and swelling, drainage is
Endodontic build-up of broken down established through the root canal or incision or both.
coronal and radicular structure while Drainage through the root canal is preferable as it
preserving individualized access to canal. allows pus, necrotic tissue, toxic products and gas to
Pre-Endodontic build-up: It may be escape. But in case if access is difficult, or tooth is very
necessary in some cases to supply a missing tender and access cavity cannot be prepared and a soft
wall with amalgam or composite or an fluctuant swelling present, then incision and drainage is
orthodontic band may be cemented over the treatment of choice.
remaining natural crown before Endodontic Drainage through the incision is made from the most
treatment is begun to prevent the rubber- dependent part of the swelling near the root apex.
dam clamp from slipping off the tooth and In case of a hard swelling, it is converted into soft, fluctuant
to facilitate proper placement of retainer. swelling by warm rinses and then the incision is made.
• Partially erupted, broken tooth or tooth prepared for In case of swelling, patient should be instructed not
crown: Cause inadequate clamp placement. to apply heat to outside of face, as it can cause sinus tract
Solution: Customize the rubber dam retainer by (fistula) leaving a scar.
modifying the jaws to adapt to a particular tooth. In case of a large swelling, after the incision is made, a
• Tooth with extreme mobility or multiple adjacent teeth drain is inserted to keep the wound open.
requiring treatment: Clamp the posterior tooth normally,
whereas a second clamp is reversed on the most anterior Principle 5: Chemoprophylaxis
tooth.
Or Patients with history of rheumatic fever or congenital heart
Clamp the posterior tooth normally, whereas anterior disease require prophylactic antibiotics to prevent bacterial
portion of dam is retained without a clamp. Endocarditis.
Two gram of phenoxymethyl penicillin 1 hour before
Situations where use of rubber dam is contraindicated: treatment and then 1 g six hours postoperatively.
• Asthamatic patients In case of allergy to penicillin, erythromycin is given.
• Patients with allergy to latex, nonlatex material will have Dose is 1 g 1 hour before treatment and 500 mg 6 hours
to be used. postoperatively.
• Mouthbreathers
Principle 6: Immobilization
Principle 2: Sterilization The affected tooth can be immobilized by relieving occlusal
This principle is discussed in detail in Chapter 12. stress or contact with the opposing tooth.
Slightly relieving occlusion in an Endodontic case,
Principle 3: Debridement lessens the possibility of traumatizing the periodontal
• The infected root canal must be cleaned of debris by ligament. Another philosophy is only to disocclude in lateral
thorough biomechanical preparation (cleaning and excursive movement.
shaping) and chemical means by use of root canal Figures 10.13 and 10.14 show relieved occlusal cusps
irrigants and disinfectants. of mandibular molar during the first appointment of
• Combination of instrumentation and irrigation help to Endodontic treatment.
remove all necrotic material and debris from the root canal
resulting in complete debridement and cleansing of root Principle 7: Avoidance of Trauma
canal.
• Presence of dead tissue in the canal prevents disinfection • Gentle handling of soft tissues
and repair. • Prevent overinstrumentation
156 Short Textbook of Endodontics
Fig. 10.13 Reduction of occlusal contacts to relieve the tooth of Fig. 10.14 Access preparation and relieved occlusal contact
occlusion during the first appointment of Endodontic treatment of mandibular molar during first appointment of Endodontic
(Courtesy of Dr Manoj Ramugade) treatment, to reduce the possibility of pain by traumatizing PDL
(Courtesy of Dr Manoj Ramugade)
• Determine accurate working length and follow it during Principle 9: Irritation by Chemicals Avoidance
instrumentation to confine all the instruments within
the root canal to minimize trauma to periapical tissues. Irrigating solutions such as sodium hypochlorite or
hydrogen peroxide, if forced through the apical foramen
Principle 8: Trephination can cause considerable pain and edema.
All such irritating drugs should be confined to the root
• Trephination means creating a surgical passage in the canal itself and should not be forced through the apical
region of root apex using a bur or a special drill to provide foramen.
a channel for the escape of pus and blood. This is done Figure 10.15 shows mind-map to remember all points
to relieve the pressure of accumulated fluid or gas in the of the principles of Endodontic treatment.
jaw bone.
• Indications: BIBLIOGRAPHY
– Acute alveolar abscess
– Teeth with large areas of rarefaction 1. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis:
Mosby, 2006.pp.120-7,
– Overfilled canal with lot of pain and discomfort 2. Grossman L, Oliet S, Del Rio C. Endodontic Practice, 11th edn.
– Postoperative pain following obturation. Varghese Publication, 1991.pp.132-44.
• Not generally recommended as it itself causes surgical 3. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics, 6th edn.
trauma. BC Decker Inc, Hamilton, 2008.pp.791-9,
Endodontic
Armamentarium:
11
CHAPTER
Instruments, Materials
and Devices
This chapter classifies the Endodontic Armamentarium according to their use in various Endodontic
procedures. Some of them have only been listed, their detailed description is given in the respective
chapters along with the procedures and techniques in which they are used.
You must know
• What Changes have Occurred in the Endodontic Armamentarium in the Practice of Modern
Endodontics?
• What are the Devices used for Enhanced Vision, lllumination and Magnification?
• What are the Instruments, Materials and Devices used as Diagnostic Aids in Endodontics?
• What is the Armamentarium for Administration of Local Anesthesia?
• What are the Materials used for Isolation of Endodontic Field?
• What is the Armamentarium Needed for Access Cavity Preparation?
• What are the Instruments and Devices for Determination of Working Length?
• What are the Materials used for Disinfection of Root Canal?
• What are the Instruments and Devices for Root Canal Preparation (Endodontic Instruments)?
• What are the Instruments used for Obturation of Root Canal System?
• What are the Instruments and Devices for Removal of Root Canal Obstructions and Fillings?
• What are the Materials used as Temporary Restorations?
• What are the Materials used for Post-Endodontic Restoration?
• What is the Armamentarium for Periradicular Surgery?
• What is the Role of Laser Device in Endodontics?
WHAT CHANGES HAVE OCCURRED IN THE • Electronic apex locators to precisely determine the
ENDODONTIC ARMAMENTARIUM IN THE working length and the apical termination position
PRACTICE OF MODERN ENDODONTICS? (apical constriction) of root canal preparation and filling.
• Improved instruments for effective coronal and radicular
In last 2–3 decades, following changes have occurred in the access cavity preparation.
Endodontic armamentarium: • Nickel-titanium Endodontic instruments for refined
• Enhanced vision with magnification devices such cleaning and shaping of canals.
as surgical operating microscope/dental operating • Thermoplasticized and newer obturation systems for
microscope. denser and three-dimensional obturation with gutta-
• Improvements in diagnostic aids: For example, percha.
– Enhanced imaging with digital radiography (RVG) • Improved and simplified post systems and core build-up
– Laser Doppler flowmeter and other newer devices materials for badly broken down teeth.
to precisely detect pulp vitality • Microsurgical instruments for periradicular surgery.
– Advanced 3D imaging—Cone beam computed • Retreatment devices for removal of old obturations and
tomography (CBCT) scans. obstructions.
Endodontic Armamentarium: Instruments, Materials and Devices 159
• Ultrasonic devices for enhanced irrigation and many • Properties of telescopic loupes:
other irrigation devices and methods. – Magnification : L oupes are available with
• Introduction of lasers in Endodontics. magnification of 2X, 2.5X, 4X, 6X, etc.
Newer armamentarium have made Endodontic 2.5X is considered to be ideal magnification with
treatment predictable, quicker and simpler too! telescopic loupes, as higher magnification causes
problems such as change in depth of field with the
WHAT ARE THE DEVICES USED FOR ENHANCED change in operator’s position, and problems related
to working distance. Also, more illumination is
VISION, ILLUMINATION AND MAGNIFICATION?
required with increase in magnification in loupes.
Earlier, the root canal system could be viewed only on the – Working distance: Distance from dentist’s eye to the
radiographs and that also gave a two-dimensional image field of treatment is the working distance.
of the three-dimensional biological system. But with the 2.5X magnification allows comfortable working
advent of optical magnification instruments such as loupes, distance thus improved posture of the operator while
microscope, endoscope and orascope, the root canal system working.
can actually be viewed in a magnified form, thereby allowing – Depth of field: It is the distance between the nearest
the clinician to perform the Endodontic procedures with and the farthest objects appearing in a sharp focus.
great precision and ease. Dental loupes provide good depth of field.
– Field of view: It is the total area visible through optical
Dental Loupes magnification.
Dental loupes provides an acceptable field of view
• Also called as surgical telescopes. required to perform regular procedures.
• Dental loupes are currently the most common – Illumination: Some of the loupes are manufactured
magnification aid used in dentistry. with the attached light sources to improve
• Dental loupes consist of convergent lenses attached to illumination.
the regular glasses of the spectacles. Figure 11.1 shows • Advantages:
photograph of Loupes. – Improved vision due to magnification
• Single lens loupes have fixed focal length and working – Improves body posture during working preventing
distance. the possible neck and back strain
• Loupes used in dentistry generally consist of multi- – Good optical properties
lens optic system called as Galilean optical system that – Acceptable weight
provides better magnification and improved working • Disadvantages:
distance. – Does not satisfy the magnification need for Endodontic
treatment which may be from somewhere around 3X
to 30X. If more than 2.5X magnification is used with
loupes, problems occur related to depth of field and
working distance
– Weight on the face and head of the operator while
working which may be quite uncomfortable.
– Optical performance not acceptable for Endodontic
purposes.
– Some clinicians may take time to get used to it.
Fig. 11.3 Photograph of head portion of dental operating Fig. 11.4 Schematic representation of DG-16
microscope (Courtesy of Seiler) Endodontic explorer
162 Short Textbook of Endodontics
through the tooth. The pulp testers operate at high Figure 11.7 shows photograph of commercially
potential difference but a very low current (mA). available caries detector dye.
– Earlier, electric pulp testing devices were not well- • Devices for transillumination test: Fiberoptic light is used
calibrated and had such a design that sometimes as light source, which can be specifically designed for
applied higher current directly to the tooth causing transillumination test.
great discomfort. Figures 11.8A and B shows photograph of fiberoptic
– Newer electric pulp tester (EPT) devices use battery light source for transillumination test.
or AC power in which the speed of delivery of current Handpiece with fiberoptic activated or other bright
can be adjusted. point light source can also be used for transillumination.
Figure 11.5 shows schematic representation of
electric pulp tester. Transillumination test has been explained in Chapter 7:
The electric pulp test has been described in Chapter Diagnosis and Diagnostic Aids in Endodontics.
7: Diagnosis and Diagnostic Aids in Endodontics.
• Device for testing pulp vitality: Laser Doppler flowmeter
and pulse oximeter assess pulpal blood flow to
determine the pulp vitality. (Explained in Chapter 7:
Diagnosis and Diagnostic Aids in Endodontics)
• Devices used for bite test:
– Cotton rolls
– Wooden end of cotton tip applicator
– Rubber polishing wheel
– Tooth slooth: Tooth slooth is specifically designed for
performing bite test. Figure 11.6 shows photograph
of tooth slooth.
It has the design that allows the biting force to be
applied selectively to one cusp at a time so that the
specific areas can be determined for the diagnosis
of incomplete crown fracture. Bite test is described
in Chapter 7: Diagnosis and Diagnostic Aids in
Endodontics.
• Stains used for caries detection and for diagnosis of Fig. 11.7 Commercially available caries detector dye
cracks or fracture: (Courtesy of Mr Amar, Dr Dabholkar’s clinic)
– Acid red in 1% propylene glycol
– Methylene blue dye
– India ink
B
Fig. 11.6 Tooth slooth (Courtesy of Dr CR Suvarna) Figs 11.8A and B Fiberoptic light source for transillumination test
(Courtesy of Dr CR Suvarna)
Endodontic Armamentarium: Instruments, Materials and Devices 163
A B
Figs 11.9A and B Access preparation bur kit showing round bur, transmetal bur, long shank round burs, safe-ended bur and X-gates
(Courtesy of Dentsply)
164 Short Textbook of Endodontics
B
Figs 11.10A and B Safe-ended carbide bur: Fig. 11.11 Gates Glidden 1 to 6
(A) Endo access bur; (B) Endo Z bur (Courtesy of Dentsply)
Figures 11.10A and B shows photograph of safe- is the narrowest diameter lying adjacent to the
ended carbide bur. handpiece. If the drill binds during use and the
These burs are used for final refinement extending instrument separates, the separation occurs at
from enamel to pulpal floor orienting the bur along the the neck and the separated part can be removed
axial walls without causing gouging. So, they are safer from the canal easily.
choice for axial wall extensions. Flame-shaped head cuts laterally and it has a
• For occlusal reduction: Fissure carbide and diamond burs safe tip to guard against perforations.
also can be used to reduce or level off the cusp tips and – The GG drills are available in various lengths such
incisal edges for two reasons: as 28 mm, 32 mm, etc.
– Disocclusion of tooth in case of inflammation. – The GG drills are available in a set of 6 instruments
– Flat cusp tips and incisal edges can be used as with a diameter ranging from 0.5 mm to 1.5 mm. The
reproducible reference points during working length specific drill size can be identified by the number of
determination. rings on the shank.
• For enlarging the orifices and preflaring of coronal Figure 11.11 shows photograph of Gates Glidden
portion of root canal: Root canal orifices have to be drills 1–6.
blended into the axial walls in order to gain straight-line GG 1: 0.5 mm diameter (ISO size # 50) with one ring on
access (SLA) so that the subsequent instruments used shank
for cleaning and shaping can enter the root canal easily GG 2: 0.7 mm diameter (ISO size # 70) with two rings
and effortlessly. This can be done using Gates Glidden on shank
drills. GG 3: 0.9 mm diameter (ISO size # 90) with three rings
on shank
Gates Glidden Drills GG 4: 1.1 mm diameter (ISO size # 110) with four rings
on shank
These are engine driven reamers used in Endodontics. GG 5: 1.3 mm diameter (ISO size # 130) with five rings
• Instrument design: on shank
– Gates Glidden (GG) drill has GG 6: 1.5 mm diameter (ISO size # 150) with six rings
- A long, thin shaft on shank.
- A flame-shaped head with a safe tip. An instrument called X gates (GG X) drill has been
Shaft is designed in such a way that the manufactured which has features of GG1 to GG4. It has
weakest part of the shaft is at the neck, which no ring on the shank. It has better cutting efficiency.
Endodontic Armamentarium: Instruments, Materials and Devices 165
Manner of Use
The GG drills are used with air motors or preferably with
electric gear reduction handpieces.
They should be inserted in the correct direction and
used passively without any pressure. They should be used
only in straight portion of canal.
Their use should follow the sequence of their sizes.
• In step-down technique, starting with larger size drill
that can be introduced into the orifice and progressing
deeper into the coronal 1/3rd of root canal with smaller
size drills.
• In step-back technique, starting with smaller size drill Fig. 11.13 Overzealous use of Gates Glidden causing
into the coronal 1/3rd of root canal and withdrawn and coke bottle effect
166 Short Textbook of Endodontics
A mind-map to remember all points of Gates Glidden • Endodontic spoon excavator or Endodontic spoon is
drills is given in Figure 11.14. slightly different from regular dental spoons in that
they have a much longer offset from the long axis of the
Hand Instruments for Access Preparation instrument for better reach inside the constricted pulp
chambers.
• Mouth mirror This is used to:
• Probe – Scoop out carious dentin
• Explorer – To excise coronal pulp tissue.
• DG-16 Endodontic explorer: It is used for location of root Figures 11.15A and B shows diagrammatic representation
canal orifices and to determine the angulation of the of DG-16 Endodontic explorer and Endodontic spoon
canals. The two ends of Endodontic explorer are sharp excavator respectively.
and angled in two different directions from the long axis Endodontic spoon excavators are designed in such a
of instrument. way that they are offset from the long axis of the instrument.
Endodontic Armamentarium: Instruments, Materials and Devices 167
B
Figs 11.15A to B Diagrammatic representation of DG-16
Endodontic explorer (A) and Endodontic spoon excavator (B)
WHAT ARE THE MATERIALS USED FOR WHAT ARE THE INSTRUMENTS AND
DISINFECTION OF THE ROOT CANAL? DEVICES USED FOR ROOT CANAL
PREPARATION?
Chemical agents for disinfection of root canal include:
• Root canal irrigants
• Decalcifying materials Classification of Endodontic Instruments
• Intracanal medicaments.
These have been discussed in detail in Chapter 15 • Grossman has classified the Endodontic instruments
Disinfection of the Root Canal System. according to their function.
170 Short Textbook of Endodontics
HAND-OPERATED INSTRUMENTS
end of the working part of instrument. Thus, the working • Color coding of instrument: Instrument handles have
part of instrument must be at least 16 mm long. A new been color coded to recognize them easily. Specific color
diameter measurement point D3 was added, according is given to the numeric diameter at Do.
to ADA specification no. 28, D3 is the diameter point
Color code Instrument number Diameter at Do (mm)
3 mm from the tip of the cutting end of the instrument.
Figure 11.19 shows diagrammatic representation of Pink #6 0.06
root canal instrument standardization. Gray #8 0.08
Purple # 10 0.10
• Taper of instrument: As per ISO standardization, there
White # 15 0.15
was a constant increase in taper of 0.02 mm (2%) per Yellow # 20 0.20
millimeter for every instrument regardless of size. Red # 25 0.25
Nowadays, instruments with greater taper such as Blue # 30 0.30
0.04, 0.06, 0.08, 0.10 and 0.12 have become popular. It Green # 35 0.35
Black # 40 0.40
means that with every millimeter increase in the length
White # 45 0.45
of the cutting blade, the width (taper) of instrument Yellow # 50 0.50
increases by 0.04, 0.06, 0.08 of a millimeter rather Red # 55 0.55
than the ISO standard of 0.02 mm/mm. These new Blue # 60 0.60
instruments with the increased taper allow for the Green # 70 0.70
Black # 80 0.80
greater coronal flaring than the 0.02 instruments.
White # 90 0.90
Some manufacturers have even made half sizes in the Yellow # 100 1.00
0.02 flare such as 2.5, 17.5, 22.5, 27.5, 32.5, 37.5. These Red # 110 1.10
have been made for shaping extremely fine canals. Blue # 120 1.20
• Working diameter of instrument: It is the product of the Green # 130 1.30
Black # 140 1.40
taper and the length of the tip, i.e.
The working diameter of an instrument = taper × length
of tip • Material of instrument : Earlier instruments were
= 0.02 × 16 manufactured using carbon steel which were susceptible
= 0.32 mm greater than the diameter at Do. to corrosion usually on contact with sodium hypochlorite
For example, No. 20 file will have working diameter of: solution and were more likely to fracture when strained
= 0.02 + 0.32 (deformed).
= 0.52 mm Now, instruments are universally made of stainless
• Tip angle of instrument: The tip angle of an instrument steel and nickel-titanium.
is about 75 ± 15o • Manufacture of instrument: Smaller size finer instru
• Length of instrument: Instruments are available in ments may break if they bind in the root canal. So, they
standard lengths of 21 mm, 25 mm, 28 mm and 31 mm. are manufactured from square blanks to make them
Short instruments are helpful in 2nd and 3rd molars and resistant to torque fractures. Triangular blanks are used
when patients cannot open the mouth wide and longer for larger instruments to improve their cutting efficiency.
instruments are often required for canines. Shorter Besides the ISO standards, the instruments and filling
length instrument such as 19 mm have also become materials have been numbered as per the standards
available now. given by American National Standards Institute (ANSI)
as follows:
ANSI number Instrument
– Manufacture: Round wire is notched to form Figure 11.22 shows a file stand with Endodontic
sharp barbs bent at an angle from the long axis to instruments arranged in sequence.
manufacture these instruments.
– Uses: K-Type Instruments
- For extirpation of vital pulp These are named so because they were first designed and
- For removal of loose debris from necrotic canals manufactured by KERR company.
- For removal of paper points or cotton pellets from
the canals K-type instruments include:
- For enlarging the canals when used in conjunction • K-Reamers
with sonic or reciprocating handpieces. • K-Files
– Manner of use: A barbed broach should be inserted • K-Flex files
in the canal only after it has been enlarged to a size
no. 25 file/reamer. It is inserted in the canal till the • Reamers: Reamers are k-type instruments.
length where it first binds, then rotated to engage the – “Reamers are Endodontic instruments that are used
pulp tissue or debris until it meets resistance against to cut and enlarge the canals by reaming or rotational
the canal walls and then gently withdrawn without drilling motion, which means penetration, rotation
twisting. and retraction”. That means it cuts by inserting in the
Increased pressure during use may embed the canal, twisting clockwise one-quarter to half turn and
barbs onto the canal walls and increased pressure then withdrawing.
during its withdrawal from the canal may cause – Stainless steel wire is ground along its long axis into
its separation in the canal and it may be almost tapered triangular cross-section (3-sided), i.e. A
impossible to remove the separated barbed broach triangular metal blank is twisted along its long axis
from the canal. to produce a K-reamer (Fig. 11.23).
• Rasps:
– Rasps are similar to barbed broaches with some TABLE 11.1 Distinguishing features of broach and rasp
differences related to taper and barb height. Broach Rasp
– Rasps have greater taper (about 0.015–0.02) and • Has larger and fine thickness • Has smaller and blunt barbs
smaller barbs as compared to Broaches. barbs
– Rasps are also used for extirpation of pulp tissue from • Lesser taper (0.007–0.01) • Greater taper (0.015–0.02)
the root canal. • Barbs present up to half of its • Barbs are present only up to
Distinguishing features between broaches and rasps core diameter, that makes it a 1/3rd of its core
weaker instrument
given in Table 11.1.
Fig. 11.22 File stand with instruments arranged in sequence. (Courtesy of Dentsply)
174 Short Textbook of Endodontics
– Cutting action occurs during retraction/withdrawal - Reaming (drilling) motion: Similar to reamer:
– Reamers have ½ to 1 cutting blade (flute) per mm of penetration, rotation and retraction.
working end – K-files have 1 ½–2 ½ cutting blades (flutes) per mm
– Reaming is the only method that produces a round, of working end.
tapered preparation in straight root canals, where the – Uses of K-files:
reamers are rotated one-half turn. In a slightly curved - Cutting and machining root dentin
canal, reamer is rotated only one-quarter turn as - Penetrating and enlarging root canals for bring-
more stress may lead to its separation (breakage) ing about shaping or preparation of Root canals.
– Uses: – Few other points about K-files:
- Cutting and machining root dentin - Smaller size K-files such as #6 and #8 files do not
- Penetrating and enlarging root canals for remove any significant amount of dentin except
bringing about shaping or preparation of Root in severely calcified canals. They are mainly used
canals. to establish patency.
• K-files - Significant wear and loss of efficiency occurs
– Files are Endodontic instruments that are used to with the repeated use of files. It is recommended
enlarge the canals by rasping motion, which means that the smaller size files be discarded after
“reciprocal insertion and withdrawal motion”. one or two uses because initially a point crack
– Stainless steel wire is ground along its long axis into develops with its use resulting in metal fatigue in
tapered square cross-section (4-sided), i.e. A square the fragile instrument which causes its distortion
metal blank is twisted along its long axis to produce and breakage with further use.
a K-file (Fig. 11.24). - Files are generally used in clockwise motion. If
– Cutting action of K-file: The tighter spiral of they are rotated in counter clockwise direction,
file establishes a cutting angle, called rake,that they are more prone to fracture.
achieves its primary action on withdrawal. It can be - Copious irrigation should be done in between
used in: using Endodontic files to prevent packing of
- Filing (Rasping) motion or push-pull motion: debris in the root canal and files should be
Instrument is placed in the canal till the desired lubricated while using in the canal.
length, pressure is exerted against the canal wall - After every use, the flutes of the files should be
and while maintaining pressure the instrument carefully inspected for any distortion or cracks.
is withdrawn without turning. The file need not Distorted files must be discarded otherwise they
contact all the root canal walls simultaneously, may break in the root canal.
it can be used by filing circumferentially around Figure 11.25 shows photograph of reamer No. 30 and
the walls. K-file No. 30.
K-Reamer
Fig. 11.23 Triangular cross-section of reamer
K-file
Fig. 11.25 Photograph showing K-reamer and K-file No. 30
Fig. 11.24 Square cross-section of K-file (Courtesy of Dentsply)
Endodontic Armamentarium: Instruments, Materials and Devices 175
C+ Files
• These are special files made for difficult and calcified
canals as they have better buckling resistance than
K-files.
• Made of stainless steel and have square cross-section.
Fig. 11.27 Tear-drop cross-section of Hedstrom file
Fig. 11.28 Hedstrom file No. 30 Fig. 11.29 Double-helix configuration of “S” file
Endodontic Armamentarium: Instruments, Materials and Devices 177
– Available as 28 mm and 32 mm long instruments. bubbles implode with a great force during positive
– Peeso reamers are usually available in a set of 6 pressure phase of oscillation. This process is called
instruments Peeso 1 to 6, identified by the number cavitation. Earlier it was thought that the main
of rings on the shank. debriding action of the ultrasonics was by cavitation.
– Peeso reamers are available in tip diameters ranging Now it is believed that debridement is caused due
from 0.7 to 1.7 mm. to the other physical phenomenon called ‘Acoustic
The tip diameter of Peeso 1 is 0.7 mm, peeso 2 is streaming’.
0.9 mm, Peeso 3 is 1.1 mm, Peeso 4 is 1.3 mm, Peeso – Circular fluid movement called Eddy flow occurs
5 is 1.5 mm and that of Peeso 6 is 1.7 mm. around the Endodontic instruments due to acoustic
Figure 11.31 shows photograph of peeso drills 1 to 6. streaming, which is the main mechanism involved in
– Cutting action: Peeso reamers have lateral cutting bringing about the cleaning effect of the irrigant in
action. the pulp space. It depends on the free displacement
– Use: Mainly used for postspace preparation in the amplitude of the file.
coronal portion of the root canal. • Use: Effective for irrigating the root canal systems for
– Caution: Peeso reamers should be used in a slow root canal cleaning. When ultrasonic oscillation is used
speed and in correct angulation to prevent lateral in conjunction with sodium hypochlorite irrigation, it
perforations or excessive removal of radicular brings about effective root canal disinfection.
dentin. • Requirements: Free vibration of file within the canal is
required for optimum cleansing action with ultrasonic
ULTRASONIC AND SONIC INSTRUMENTS oscillation.
So, it is recommended that:
Ultrasonic Devices for Endodontic Use For optimum cleansing action with ultrasonic
oscillations:
• Principle: Sound is used as energy source at 20–25 KHz – Canals should be enlarged and prepared, i.e. bio
for the three-dimensional activation of an Endodontic mechanical preparation of the canals should be
file (K-file) resulting in three-dimensional activation of completed.
the file in the surrounding medium. – Use a smaller size Endodontic file, such as of size No.
• Mechanism: Two physical actions occur during 15, that has minimal contact to the walls of the root
ultrasonic oscillation namely: cavitation, acoustic canal.
streaming. – Files should be loose in the canal.
– Bubbles are formed by the free ultrasonic vibration – Ultrasonic oscillation with an Endodontic file
of Endodontic file within the fluid of the canal during combined with sodium hypochlorite irrigation
negative pressure oscillation and these unstable brings about effective cleaning and disinfection of
root canals.
• Types: Ultrasonic devices of 2 types can be used:
1. Piezoelectrical.
2. Magnetostrictive.
Piezoelectrical unit generates less heat, does not
require cooling system and transfers more energy
to the file as compared to the magnetostrictive unit
and hence are more preferred devices.
Figures 11.32A and B show photograph of
ultrasonic device and ultrasonic tips respectively for
Endodontic use.
A B
Figs 11.32A and B Ultrasonic device and ultrasonic tips for Endodontic use. (A) Ultrasonic unit for Endo purpose; (B) Ultrasonic tips
(Courtesy of Sybron Endo)
This has been explained in detail in Chapter 14 Cleaning Uses of Ultrasonics and Sonics in Endodontics
and Shaping of the Root Canal System Including Working (Endosonics)
Length Determination and Chapter 15 Disinfection of the
Root Canal System. • Removes isthmus tissue between canal
• Mechanism: Sonically powered files oscillate up and • Helps in location of orifices
down in a longitudinal oscillation motion to bring about • Smoothens the axial walls and floor of the pulp chamber
preparation of root canals. during access cavity preparation finishing
• Uses: • Removes pulp stones smoothly and safely from pulp
– Remove pulp remnants and necrotic debris from chamber without scoring
root canals. • Opens calcified canals
– Rasp and remove dentin during preparation of root • Brings about effective irrigation when used along with
canals. sodium hypochlorite and results in cleaner root canals
• Requirements: Sonic instruments should be loose and • It can be used for obturation of root canal (Ultrasonic-
free to oscillate within the root canal. So, canals should plasticized gutta-percha obturation technique)
be enlarged to the working length and apical part of root • Used during retreatment to remove gutta-percha, to
canal prepared using conventional files after which the remove cement around posts that aids in post removal
sonic files are used. • It can be used to help retrieve separated files
• Sonic length: The Sonic instruments, with 1.5–2 mm safe • It can be used for MTA placement in the canals.
tips, begin their rasping action 1.5–2 mm from the apical
stop. This is called ‘Sonic length’. NICKEL-TITANIUM HAND AND ROTARY
• Examples:
INSTRUMENTS
– Rispi sonic files
– Shaper sonic files • Nitinol alloys contain 55% nickel and 45% titanium
– Trio Sonic files by weight. (Ni—Nickel, Ti—Titanium, NOL—Naval
of which shaper sonic files are found to be more Ordnance Laboratory).
effective for widening the canals than Rispi Sonic • Property of Super elasticity: It is the property of nickel-
files. But Rispi Sonic files are less aggressive than titanium alloy that allows it to return to its original
shaper Sonic files. shape following significant deformation. This property
A mind-map to remember all points of Sonics of nickel-titanium makes Endodontic files more flexible,
and Ultrasonics in Endodontics is given in Figure better able to conform to curvatures of canal, resist
11.33. fracture and wear less than stainless steel instruments.
180 Short Textbook of Endodontics
• Land: The surface formed in between flutes that projects Comparative Properties of Stainless Steel
axially from the central axis. and Nickel-titanium Instruments
• Cutting/Leading edge: The surface where the flute and
land intersect that has the greatest diameter and follows See Table 11.4.
the groove as it rotates is called the cutting edge or blade
of file. Phases of Nickel-titanium Alloys
• Helix angle: It is the angle formed by the cutting edge
with the long axis of the file as shown in Figure 11.35. It
augers debris collected in the flute from the root canal.
• Rake angle: It is the angle formed by the cutting edge
with the radius of the file when the file is sectioned
perpendicular to its long axis. If this angle is obtuse, it
is called positive or cutting and if it is acute, it is said to
be negative or scraping.
• Pitch of file: It is the distance between a point on the
cutting edge and the corresponding point on the
adjacent cutting edge as shown in Figure 11.35.
When the instrument is designed in such a way
that there is balance between the helical angle and Phase Transformation
pitch of file, there is better cutting action and debris is
effectively removed from the canal. Also the instrument • On heating, Martensite → R-phase → Austenite
is prevented from inadvertently screwing in the canal. This is called forward transformation.
Nickel-titanium instruments are superior to stainless • On cooling, Austenite → R-phase → Martensite
steel instruments for Endodontic use. This is called reverse transformation.
The comparative properties of stainless steel and nickel- • During Endodontic use:
titanium instruments are given in Table 11.4. – External stresses cause transformation of Austenitic
crystalline phase to martensitic crystalline phase.
Martensitic crystalline phase can accommodate
stresses without resulting in proportional strain.
– When the stress is released, reverse transformation
to austenitic crystalline phase occurs and the
instrument recovers its original shape in the process.
• Carefully evaluate root anatomy as well as extent and position of canal • Do not force the file
curvatures from radiographs • Do not overuse the files
• Prepare adequate access cavity with straight-line access, prior to using • Do not use Ni-Ti files to bypass the ledges
nickel-titanium (Ni-Ti) files • Do not change the direction of the instrument suddenly by jerky or
• Enlarge and flare the orifices and the coronal 1/3rd of canal adequately jabbing movements
before you use Ni-Ti files • Do not apply additional pressure if the easily progressing instrument in
• Use hand files to negotiate the canal and create a glide path with smaller canal, feels as if it hits bottom
K-files such as 10, 15, and possibly 20, before using Ni-Ti rotary files. Thus, • The Ni-Ti rotary file should not remain in the canal for more than 2 to 5
Ni-Ti rotary files should be introduced in the root canal only after glide seconds
path has been established • Do not cause ‘taper lock’ or ‘frictional fit’ of the rotary file within the canal.
• Discard these files after single use ideally (When entire length of the file blade is to cut a smaller size canal, the
• Measure each file length frictional fit of instrument engages root dentin and causes instrument
• Frequently inspect the instruments for any bend or signs of fatigue to lock. Rotating the file counter-clockwise will remove it from the canal.)
• Advance nickel-titanium increments passively in the canal • Do not work in a dry canal
• While using Ni-Ti files, as soon as resistance is encountered, stop • Do not advance larger increment of rotary file into the canal since it may
immediately and before you continue, increase coronal taper and prepare act as a drill and will increase stress on metal
the canal till the working length with smaller size K-files • Do not cut with the entire length of the blade
• Lubricate the Ni-Ti files with chelating agent during instrumentation
• Irrigation with sodium hypochlorite after use of each file
• Recapitulate with smaller stainless steel K-files to ensure patency till length
in between use of rotary Ni-Ti files
• A pecking, up and down motion with rotary Ni-Ti files is recommended to
prevent screwing in of file and to distribute stresses away from the point
of maximum flexure of the instrument
that they are quite effective in shaping the root canal #15 and #20 before introducing the Ni-Ti rotary file in
systems. the root canal
• Ni-Ti files with the design of radial lands can be used as • Use gentle/light touch and low speed (rpm)
reamers in 360 degrees motion as opposed to traditional • Crown-Down sequence should be followed
reamers with more acute angles. In this, there is a • Replace rotary instruments frequently.
new design of rotary file, in which an identical hand
instrument is available. Also, a converter handle is Separation of Nickel-titanium Instruments
available that allows the operator to use the rotary file
as a hand instrument. Cohen classified instrument separation of nickel-titanium
• Ni-Ti instruments are more efficient and safer when used rotary files into:
passively.
• Two instrument motions which are recommended
include:
1. Gentle pecking motion: Up and down movements
2. Lateral brushing motion: Mainly recommended for
Protaper shaping files.
According to the American Association of Endodontists
(AAE), the “Golden Rules” for Ni-Ti Rotary Preparation
include:
• Case difficulty should be assessed
Cyclic Fatigue
• Adequate access must be prepared
• Preparation with hand files up to size No. 20 prior to • When an instrument rotates in a curvature
use of rotary files, which means glide path must be – It gets compressed on inner side of curve,
established with pathfinder files or smaller K-files #10, – It gets stretched on outer side of curve.
Endodontic Armamentarium: Instruments, Materials and Devices 183
Two main factors that impact the shaping potential of Quantec File System
Ni-Ti rotary instruments include: Cross-sectional design
and tip configuration. All the currently available Ni-Ti • Cross-sectional design: S-shaped design with double
rotary systems have noncutting tips. Some rotary systems helical flutes, radial lands—present, rake angle—positive
have radial land areas while some systems have nonlanded rake angle
design. • Tip configuration: Both cutting and noncutting tips are
• Presence of radial lands make the preparation slower available
but safer. Examples of rotary systems which are radial- • Taper: Fixed taper 2%, 3%, 4%, 5%,6%,8%,10%,12%. Uses
landed include: Profile system, Quantec and K3. Graduated taper technique.
• Rotary files with nonlanded areas cut rapidly but can • Recommended speed: 300–350 rpm
lead to preparation errors. Examples of rotary systems • Other features: S-shaped design minimizes its contact
which are nonlanded include: Protaper, RaCe. with the canal, thus reducing the torque. 0.02 tapered
Few of the currently available Ni-Ti rotary systems with files are available in sizes of #15 to #60.
their specific design features are given below. The technique
and strategy of use of few of them are discussed in detail in Protaper
Chapter 14: Cleaning and Shaping of the Root Canal System
Including Working Length Determination. • Cross-sectional design: Convex triangular cross-section,
sharp cutting edges, radial lands—no radial lands, rake
Greater Taper (GT) angle—positive.
• Cross-sectional design: Three U-shaped grooves, radial • Tip configuration: Noncutting.
lands: Present, rake angle: Neutral • Taper: Progressive taper. Variable taper along the length
• Tip configuration: Noncutting of cutting blades improves flexibility, cutting efficiency
• Taper: Fixed taper 2, 4, 6, 8, 10 and 12% and safety.
• Recommended speed: 150–300 rpm • Recommended speed: 250–350 rpm.
• Other features: Available in ISO tip sizes of 20, 30 and 40, • Other features: Has changing helical angle and pitch
having a maximum diameter of 1.50 mm. It has variable over cutting blades that prevents instrument from
pitch. screwing into the canal. Available as 3 shaping files: SX,
S1, S2 and 3 finishing files: F1, F2, F3. Explained in detail
Profile in Chapter 14: Cleaning and Shaping of the Root Canal
System Including Working Length Determination.
• Cross-sectional design: Three U-shaped grooves, radial
lands—present, rake angle—Negative rake angle Hero 642
• Tip configuration: Noncutting
• Taper: Fixed taper 2%, 4%, 6% • Cross-sectional design: Trihelical Hedstrom design,
• Recommended speed: 150–300 rpm radial lands—no radial lands, rake angle—positive rake
• Other features: Earlier was available as series of 29 angle
instruments, in which each file increased by 29% instead • Tip configuration: Noncutting
of 0.05 in between sizes. Has 20 degrees helical angle. • Taper: Fixed taper 2%, 4%, 6%
• Recommended speed: 300–600 rpm
Light Speed Instruments • Other features: Available in sizes of #20 to #45. The
trihelical, sharp blades are followed by recessive lands
• Cross-sectional design: Three U-shaped grooves, radial that do not extend axially to the circumference, which
lands—present, rake angle—neutral is designed to reduce stress.
• Tip configuration: Noncutting
• Taper: Specific instrument sequence will produce K3 Rotary System
tapered shape
• Recommended speed: 750–2000 rpm • Cross-sectional design: Three asymmetric flutes, radial
• Other features: Light speed instruments are slender lands—present, rake angle—positive rake angle
instruments with thin parallel shaft. Its noncutting tip • Tip configuration: Noncutting
with unique, short, flame-shaped working end similar • Taper: Fixed taper 2%, 4%, 6%
in configuration to the Gates Glidden drill. • Recommended speed: 200–300 rpm
186 Short Textbook of Endodontics
• Other features: It is similar in concept to Quantec file • Spreaders are available as:
system. Due to its cross-sectional geometry, these are – Hand-held instruments
among the most resistant to fracture. It has variable pitch – Finger-held instruments
and variable core diameter. Finger-held spreaders are preferred because in case
of hand-held spreaders the tip of the working end is
Reamer with Alternating Cutting Edges (RaCe) offset from the long axis of the handle which can cause
strong lateral wedging forces on the working end if the
• Cross-sectional design: Triangular cross-section, few instrument is not used carefully. Also, the hand-held
files have square cross-section. Radial lands—no radial spreaders do not have standardized size and shape.
lands, Rake angle—positive Figure 11.39 shows photograph of the finger spreader
• Tip configuration: Noncutting of size #30 and Figure 11.40 shows photograph of hand-
• Taper: Fixed taper 2%, 4%, 6%, 8%, 10% held spreader.
• Recommended speed: 300–600 rpm • Spreaders are available in the sizes of 15–45 and are color
• Other features: It incorporates alternating nonspiralled coded as per the ISO standardization.
and spiralled segments along its working length. This Nonstandardized spreaders with larger taper are also
design minimizes torsion of engagement and that available.
resulting from screwing-in forces. • Spreaders are made of stainless steel. Nowadays nickel
titanium finger-held spreaders are also available that
Flex Master can reach more apically in the canal and useful for
penetration in the curved canals due to their flexibility
• Cross-sectional design: Convex triangular shape, sharp and other properties.
cutting edges, radial lands—no radial lands, Rake
angle—positive Pluggers
• Tip configuration: Noncutting • Plugger is an instrument with blunt end used in vertical
• Taper: Fixed taper 2%, 4%, 6%. Intro file has taper of 11% compaction obturation of gutta-percha.
• Recommended speed: 150–300 rpm • Pluggers are available as:
• Other features: It has individual helical angle for each – Hand-held instruments
instrument size. This reduces the screwing-in forces. – Finger-held instruments
Finger-held instruments are preferred because
Newer Systems the working tip of the hand-held instrument is offset
Revo S system, WaveOne single-file reciprocating system,
Reciproc system, Protaper Next system and the latest
self-adjusting file system have been explained in detail in
Chapter 14: ‘Cleaning and Shaping of the Root Canal System
Including Working Length Determination’, along with their
techniques of use.
Spreaders
• A spreader is a tapered, pointed instrument used in
the lateral compaction obturation with gutta-percha
to displace gutta-percha laterally to create space for Fig. 11.40 Hand-held spreader for obturation
additional accessory gutta-percha cones. (Courtesy of Dentsply)
Endodontic Armamentarium: Instruments, Materials and Devices 187
from the long axis of the handle which can cause For Delivery of Sealers in the Root Canal
strong lateral wedging forces on the working end
if the instrument is not used carefully. Also, finger- Sealers can be coated on the walls of root canal using:
held instruments provide better tactile sensitivity • Instrument called Lentulo spiral
than the hand-held instruments. Figure 11.41 shows • Bispiral
photograph of finger-held plugger and Figure 11.42 • File or reamer
shows photograph of hand-held plugger. • The master cone itself
• Finger pluggers are available in the sizes of 15–140 and • Paper points or
are color-coded as per the ISO standardization. Hand • Ultrasonic tips.
plugger does not have standardized size, shape and
color. Lentulo Spiral
• Pluggers have larger diameter than spreaders and have • Lentulo spiral is used in a slow-speed contra-angle
a blunt end. handpiece to deliver the sealer cement into the root
• Uses of pluggers: canal, i.e. for the application of sealer cement to the root
– Vertical and lateral compaction of warm gutta- canal walls during obturation.
percha during obturation. Figure 11.43 shows photograph of a lentulo spiral.
– To carry small sections of gutta-percha into the canal • While using lentulo spiral it is important that it is started
during sectional method of obturation. and stopped outside the root canal otherwise it may cut
– To pack materials such as calcium hydroxide and into the wall of root canal and even break.
Mineral Trioxide Aggregate (MTA) into the canals. • The spiral should be large to drive the paste forward so
Besides spreaders and pluggers, certain heat carriers are that the material gets squeezed between the spiral and
available which transfer heat in the root canal for the apical the root canal walls.
and lateral displacement of gutta-percha. • Other uses of lentulo spiral: It can also be used to place
Commercially available heat carriers include Endotec, dressings in the root canal such as calcium hydroxide.
Touch ‘N Heat and System B devices. Lentulo spiral and bispirals have been explained in
These heat carriers and many other obturation systems Chapter 16: Obturation of Root Canal System.
have been explained in detail in the Chapter 16: Obturation
of Root Canal System. WHAT ARE THE INSTRUMENTS
AND DEVICES USED FOR REMOVAL
OF ROOT CANAL FILLINGS AND OTHER
OBSTRUCTIONS IN ROOT CANAL?
Removal of Gutta-percha
Gutta-percha from the root canal can be removed
progressively by dividing the root canal into:
• Coronal 1/3rd
• Middle 1/3rd
• Apical 1/3rd.
Fig. 11.41 Finger plugger for obturation
(Courtesy of Dentsply)
Fig. 11.42 Hand-held plugger for obturation Fig. 11.43 Photograph showing lentulo spiral
(Courtesy of Dentsply) (Courtesy of Dentsply)
188 Short Textbook of Endodontics
• Currently, rotary instrumentation is the most efficient Such as Gates Glidden drills and Peeso reamers effectively
method for removal of gutta-percha. remove gutta-percha from the coronal and straight portion
• Rotary files should be used at low speed (900–1200 rpm) of the root canal.
and with caution to prevent file separation.
• There is commercially available Endo-Retreatment Kit Ultrasonic Instruments
containing rotary files—D1 D2 D3 in this order having
one, two and three rings respectively on their shaft. D1 Piezoelectric ultrasonic tips can be used to rapidly remove
D2 and D3 are used at the speed of 500 to 700 rpm. Figure gutta-percha from the root canals by producing heat that
11.44 shows the photograph of these rotary files. thermosoftens the gutta-percha.
– D1 has cutting surface blade of 16 mm, 11 mm
handle, one white ring and a taper of 9%. Heated Pluggers
– D2 has cutting surface blade of 18 mm, 11 mm
handle, two white rings and a taper of 8%. • Heated plugger can be used to sear off the gutta-percha
– D3 has cutting surface blade of 22 mm, 11 mm from the coronal portions of the root canal.
handle, three white rings and a taper of 7%. • Another technique involves placing and plunging
– D1, D2 and D3 are used in coronal, middle and apical a heated instrument into the gutta-percha and
thirds of the root canal, respectively. immediately withdrawing it and then quickly inserting
Besides this system, there are few other new systems size #35, #40 or #45 Hedstrom file and gently screwing it
with rotary files for removal of old obturation in case of into the thermosoftened gutta-percha so that it solidifies
retreatment. on the flutes of Hedstrom file and entire or most of the
gutta-percha filling comes out with the file.
In cases where gutta-percha extends beyond the
apical foramen, the above technique can safely remove
over-extended gutta-percha.
• Specific electric heat carriers also can be used to thermo-
soften and remove increments of gutta-percha from the
root canal.
Chemicals
Gutta-percha solvents include chloroform and xylol.
• These solvents chemically soften the gutta-percha that
can be removed by sequential instrumentation with
K-files or H-files.
• Irrigation with chloroform is combined with watch-
winding motion use of files that creates space for use of
Fig. 11.44 Photograph showing the rotary Endodontic re-treatment larger files.
files—D1, D2, D3 in this order used for removal of GP root canal • Softened gutta-percha comes on the cutting flutes of
filling (Courtesy of Dentsply) files as they are withdrawn.
Endodontic Armamentarium: Instruments, Materials and Devices 189
• The solvent filled canals can be dried using paper points cement has sufficient strength to withstand the masticatory
and this is called wicking action which helps to remove forces.
the residual sealer and gutta-percha from the root Temporary cements include:
canals.
Other details of gutta-percha removal techniques are Cavit
explained in detail in Chapter 22: Endodontic Failures and
Nonsurgical Endodontic Management. • It is a premixed material for use as temporary cement.
• Composition: Zinc oxide, calcium sulfate, glycol,
Removal of Silver Points polyvinyl acetate, polyvinyl chloride, triethanolamine.
• Cavit cement sets as it absorbs fluid.
In an old root canal treated case filled with silver point, • For adequate seal, it should have depth of at least
lateral retention of silver point in the canal might have 3.5 mm.
been reduced due to chronic leakage and corrosion of silver
points and if the butt end of silver point is easily accessible in Intermediate Restorative Material (IRM)
the pulp chamber, then silver point removal is accomplished
quite easily. • It is a polymer resin-reinforced zinc oxide cement
• But most of the times, the butt end of silver point is • Available as powder and liquid in mixing capsules
embedded in the cement, composite or amalgam core. • Its compressive strength is double that of Cavit.
So, the initial access is made with round burs with It has been found to cause extensive marginal leakage.
extended shanks to carefully remove the core material
without inadvertently shortening the silver points. TERM
• Then ultrasonic instruments can be used to carefully
“brush-cut” the core material to expose the silver point • It is light cured filled composite resin which can be used
which can be then grasped using a suitable grasping as temporary restoration.
instrument such as Steiglitz pliers. • Composition: Urethane Dimethacrylate (UDMA) poly
• Ultrasonic energy can also be used when silver point lies mers, inorganic radiopaque filler, pigments, initiators.
below the orifice to disintegrate the interface within the • Adequate seal can be achieved with it even at the
canal and enhance the removal of silver point. thickness of 1 to 3 mm.
Figure 11.45 shows photograph of a commercially
Removal of Obstructions from Root Canal available temporary restorative cement.
such as Separated Instruments
Various microtube removal techniques have been currently
introduced to aid in the removal of the obstruction from
the root canal.
The Masserann kit, instrument removal system (IRS),
endoextractor system (EES) are few commercially available
kits that can be used for removal of obstructions such as
separated instruments from the root canal.
WHAT IS THE ARMAMENTARIUM FOR WHAT ARE THE MATERIALS USED FOR POST-
PERIRADICULAR SURGERY? ENDODONTIC RESTORATION?
For details refer to Chapter 26 Surgical Endodontics. Instruments for Postspace Preparation
• BP blade no. 15 or microsurgical scalpel
• Periosteal elevator • Peeso drills can be used for postspace preparation
• Microexplorer, endoexplorer • Various postspace preparation drills are available with
• Microtissue forceps the preformed post systems.
• Miniature handpieces Flow charts 11.1 and 11.2 list the materials used for post-
• Straight handpiece with different burs Endodontic restoration. They have been discussed in detail
• Sterile saline in Chapter 21 Restoration of Endodontically Treated Teeth.
• Sterile cotton, cotton pliers
• Surgical forceps WHAT IS THE ROLE OF LASER
• Curettes
DEVICE IN ENDODONTICS?
• Root-end filling materials:
– Amalgam Different types of lasers used in dentistry:
– Mineral trioxide aggregate (MTA) • Er:YAG laser
– Composite resin system (Retroplast) – Effective for drilling and cutting enamel and dentin.
– Intermediate restorative material (IRM) • CO2 laser
– Super-EBA – Quite effective in soft tissues of oral cavity. But not
– Glass ionomer cements suitable for drilling and cutting enamel and dentin.
– Resin cements such as Diaket
• Micromirrors
• Microcondensers or microburnishers and pluggers of Flow chart 11.2 Classification of core materials for restoration of
Endodontically treated teeth
different sizes
• Needle holder, suturing needle, suturing material
• Hemostatic agents:
↓ ↓
Collagen-based Noncollagen based
– Collacote – Bone wax
– Collastat – Ferric sulfate
– Gelfoam
– Thrombin
Flow chart 11.1 Classification of post systems for restoration of Endodontically treated teeth
Endodontic Armamentarium: Instruments, Materials and Devices 191
This chapter explains the importance of infection control and the various methods to achieve effective
infection control in dental practice. It describes the ways to take proper care and about sterilization of
various Endodontic instruments.
You must know
• Why is Effective Infection Control Important in Endodontics?
• How to Achieve Effective Infection Control in Dental Practice?
• What is Sterilization and Disinfection?
• How to Take Proper Care of Endodontic Instruments?
• What are the Commonly Employed Methods of Sterilization/Disinfection of Various
Endodontic Instruments?
Protection of Patients
Infection should not get transmitted from one patient to
other patient due to use of same infected instruments
Protection of Dental Health Care Personnel
without sterilizing them.
All dental health care personnel (including both those that The dental team should never be responsible for
are directly involved and those that are indirectly involved introducing infection in patients due to lack of adopting
in patient care) are at risk for exposure to a wide variety of appropriate infection control methods.
Asepsis and Sterilization of Endodontic Instruments 193
Sterile instruments and proper techniques should be needles, scalpel blades, Endodontic instruments and
used to avoid contamination by microorganisms during other items that can cause injury to skin. Gauze or cotton
Endodontic therapy in order to prevent postoperative rolls soaked in blood or saliva are also regulated medical
infection. waste and should be appropriately disposed.
Transmission of infection can occur in 2 ways: (Cross- • It is recommended that there should be separate areas
infection) in the operatory for the cleaning/sorting/packaging of
contaminated instruments for sterilization.
• Aerosols generated during dental procedures can
spread throughout the room, so all surfaces need to be
disinfected. Doors, drawer pulls should also be covered
with barriers or disinfected routinely.
• High-volume evacuation can greatly reduce the number
of bacteria in dental aerosols and should be used when
HOW TO ACHIEVE EFFECTIVE INFECTION using high-speed handpiece or ultrasonics.
CONTROL IN DENTAL PRACTICE?
Considerations for Dental Personnel
Occupational Safety and Health Administration (OSHA),
American Dental Association (ADA), Center for Disease • Vaccination: All dental health care personnel should be
Control (CDC) and other Governmental and Non- vaccinated against infectious diseases such as hepatitis
Governmental agencies give recommendations for infection B, influenza, etc.
control. • Protective attire and barrier techniques:
These guidelines must be followed by the dental team. – Protective clothing such as gowns, aprons, lab coats,
clinic jackets, either disposable or reusable must be
Considerations for Dental Operatory worn. Endodontic surgery will require long sleeved
uniforms.
• Operatory surfaces such as over-head light handles, Contaminated laundry should not be taken home
X-ray unit heads, dental chair switches and any other for wash to avoid transmission of infection to family
surface likely to become contaminated with potentially members.
infectious material should be covered or disinfected. – Protective eyeglasses with solid side shields are
Protective coverings can be in the form of clear plastic required when splashes or sprays of infectious
wrap, special plastic sleeves, etc. These covers should materials are anticipated.
be changed between patients. – Use of disposable latex or vinyl gloves and masks.
• Endodontic microscopes: Handles and controls Gloves should be replaced after each patient
of microscope should be covered with barriers. contact.
Microscope manufacturer’s guidelines should be used Commonly available masks protect the wearer
for disinfection of microscope. only partially. Small droplets containing bacteria
• Sensors of digital radiography are covered with single- can pass through them. If the mask becomes wet, it
use plastic sleeves for each patient. should be changed immediately.
• Dental unit water lines should be periodically flushed. Sterile gloves to be worn for surgical procedures.
This can be done with water or a 1:10 dilution of 5.25% Examination gloves may be contaminated and may
sodium hypochlorite to reduce biofilm formation. harbor microbes. Since gloves do not give total
Biofilm is sticky water line with bacteria, that can protection, chlorhexidine disinfectant hand wash
travel upstream in dental unit water lines due to slow can be used due to its property of substantivity, it
movement of water. bonds to skin and maintains antibacterial action for
Flushing water lines for 20–30 seconds between longer time as compared to other scrubs.
patients is recommended to avoid transmission of Polyethylene gloves can be worn over treatment
microbes from one patient to the next. gloves to prevent contamination of objects, such as
• Waste management: Sharps are included in regulated drawers, light handles or patient charts.
medical waste category and should be discarded in a Figure 12.2 shows photograph of disposable
rigid container with ‘biohazard’ label. Sharps include examination gloves, mask and protective eye glasses.
194 Short Textbook of Endodontics
Fig. 12.3 A mind-map to remember all points of infection control in dental practice
Asepsis and Sterilization of Endodontic Instruments 195
A B
Figs 12.4A and B Photograph showing commercially available front loading autoclave (Courtesy of Mr Amar, Dr Mukul Dabholkar’s clinic)
196 Short Textbook of Endodontics
4. Cold chemicals: A
B
Figs 12.5A and B Glass bead sterilizers. (A) As seen from front; (B) As
seen from above. Note the different timings required for sterilization
of various instruments are mentioned on the lid (Courtesy of Dr
Nishant Singh)
• Recommended only for those items that cannot be heat
sterilized. Preparation of Instruments for Sterilization
• They usually require extended soak times.
Handling, cleaning and packaging of contaminated
HOW TO TAKE PROPER CARE OF instruments are frequent sources of injury and possible
infection.
ENDODONTIC INSTRUMENTS?
Reusable instruments that become contaminated after
Effective care for Endodontic instruments involves: use are immediately taken to a dedicated area for removal
• Preparation of instruments for sterilization of gross debris by scrubbing or by use of ultrasonic
• Sterilization proper cleaner. Clean, dry instruments can then be subjected to
• Effective storage of instruments. sterilization process.
Asepsis and Sterilization of Endodontic Instruments 197
Care of Instruments
Sterilization Proper
Clean, dry instruments can now be made sterile by
appropriate methods of sterilization.
According to CDC guidelines about sterilizers, instru
ments should be dried before removing from the sterilizer
as wet wraps may tear easily or may allow microbes to reach
the sterile contents. In addition, cooling will avoid thermal Fig. 12.7 Photograph showing Endo box for keeping files
injury to the personnel. (Courtesy of Dr Mahashabde, Dr Rajesh Shivhare’s clinic)
198 Short Textbook of Endodontics
Endodontic Access
Cavity Preparation
This chapter discusses in detail the first step of Endodontic treatment, i.e. access cavity preparation
of root canal and explains how Endodontic success greatly depends on a good access.
You must know
• What is Endodontic Triad?
• What is Coronal Access Cavity Preparation of the Root Canal?
• What are the Objectives of Access Preparation?
• What are the Principles of Endodontic Access Cavity Preparation?
• What are the Guidelines to be Followed for an Optimum Access Cavity Preparation?
• What is the Armamentarium Needed for Access Cavity Preparation?
• Which are the Steps of Access Cavity Preparation?
• What are the Specific Features of Access Preparation of Individual Teeth and Possible Errors
Related to Them?
• Which are the Challenging Access Cavity Preparations and How to Deal with them?
• What Errors can Occur During Access Cavity Preparation?
Fig. 13.1 Objectives of access preparation Fig. 13.2 Factors affecting extension of access preparation
Endodontic Access Cavity Preparation 201
A B A B
Figs 13.3A and B (A) Dentinal shelf obstructing the straight-line Figs 13.4A and B (A) Mouse-hole effect; (B) Correcting the mouse
access, dotted line shows the required extension; (B) Shamrock hole effect and optimum extension of access preparation
preparation that provides straight-line access (SLA) to the apex
Access preparation needs to be extended at the expense orifice. This will eliminate the mouse-hole and the orifice
of coronal tooth structure shown by dotted line in Figure will now be entirely on the pulpal floor.
13.3A for unrestrained access of instrument—Shamrock Figure 13.4A shows under extended access preparation
preparation (Fig. 13.3B) with mouse hole effect.
• Convenience form: “Convenience form is that form Figure 13.4B shows correcting the mouse hole effect and
of the access cavity preparation that allows adequate optimum extension of access preparation.
observation and unobstructed access of Endodontic
instruments into the canal orifices and ultimately to the WHAT ARE THE GUIDELINES TO BE FOLLOWED
apical foramen.” FOR AN OPTIMUM ACCESS CAVITY
– The overhanging roof of the pulp chamber needs to PREPARATION?
be removed so that the orifices can be easily located
and visualized. • Guidelines: Let us consider the 10 guidelines given in
– The walls of access preparation should be made Cohen’s Pathways of Pulp, 9th Edition, as Golden rules for
smooth and occlusally diverging so that the the completion of an optimum access preparation and
instrument can freely slide down the orifices into remember them with the help of following sentence:
the canals. Very Easy Preparation Requires Root Canal Details
– Root curvatures and the angle at which the canal to be Learnt and Implemented Throughly, i.e. Visualize,
leaves the pulp chamber should be considered and Evaluate, Prepare, Remove, Remove, Create, Delay,
the access preparation modified accordingly. Locate, Inspect, Taper.
Fig. 13.5 Mind-map showing details of visualization clinicians determine the number and location of orifices
of the likely internal anatomy on the pulp chamber floor:
• Law of Centrality: The pulp chamber floor is always
located in the center of the tooth at the level of the CEJ
• Law of Concentricity: The pulp chamber walls are always
concentric to the external surface of the tooth at the
level of the CEJ, which means, the external root surface
anatomy reflects the internal pulp chamber anatomy.
• Law of the CEJ : At the level of the CEJ, the distance from
the external surface of the clinical crown to the wall of the
pulp chamber is the same throughout the circumference
of the tooth. The CEJ is the most consistent, reproducible
landmark for locating the position of the pulp chamber.
• First law of symmetry: Canal orifices are equidistant from
a line drawn in mesiodistal direction through the pulp
chamber floor. Exception is maxillary molars.
Figure 13.7 shows schematic representation of the
first law of symmetry.
• Second law of symmetry: Canal orifices lie on a line
perpendicular to a line drawn in a mesiodistal direction
Fig. 13.6 Estimation of depth of pulp chamber by keeping the
across the center of pulp chamber floor. Exception
handpiece with the bur alongside a preoperative radiograph
is maxillary molars. Figure 13.8 shows the schematic
representation of the second law of symmetry.
• Law of color change: The color of the pulp chamber floor
is always darker than the walls.
Evaluation of the Cementoenamel • First law of orifice location: Orifices of root canals are
Junction and Occlusal Anatomies always located at the junction of walls and floor.
• Second law of orifice location: Orifices of root canals are
One cannot rely completely on occlusal anatomy to prepare located at the angles in the floor-wall junction.
the access cavity as the crown might have been destroyed by • Third law of orifice location: Orifices of root canals are
caries or reconstructed with restorative materials, thus there always located at the terminus of roots’ developmental
can be a change in the morphology of the tooth. fusion lines.
According to studies by Krasner and Rankow, cemento-
enamel junction (CEJ) is the most important landmark for Preparation of the Access Cavity Through Lingual
determining the location of pulp chambers and root canal
and Occlusal Surfaces
orifices.
They found that anatomy of pulp chamber floor is Access cavity is prepared through the lingual surface in
specific and consistent and they have given the following anterior teeth and the occlusal surface in posterior teeth.
guidelines or laws of pulp chamber anatomy to help (Fig. 13.9).
Endodontic Access Cavity Preparation 203
Fig. 13.18 EDTA gel (Glyde) for lubrication (Viscous chelator) Fig. 13.20 Temporary filling
(Courtesy of Dentsply)
WHAT IS THE ARMAMENTARIUM NEEDED - Round diamond burs (for access through
FOR ACCESS CAVITY PREPARATION? porcelain)
• Magnification using dental operating microscope - Long shank round burs
(DOM) or surgical loupes (2.5X, 4X) can be really helpful. - Transmetal burs for penetration through metal
Figure 13.21 shows schematic representation of the - Tapered fissure carbide bur or a diamond bur
dental operating microscope (DOM). with rounded cutting end
Figure 13.22 shows schematic representation of a – For axial wall extensions
magnifying loupe. (The dental operating microscope - Safe-ended diamond and tungsten carbide
(DOM) and the magnifying loupes have been described burs (tip/end is noncutting, sides are cutting),
in detail in Chapter 11: Endodontic Armamentarium: for example, endo access bur, endo Z bur (Figs
Instruments, Materials and Devices). 13.24A and B), safe nonend cutting bur
• Handpieces: These can be used for final refinement extending
– High speed handpiece: For initial penetration from enamel to the pulp floor orienting the axial
– Slow speed handpiece: For deeper penetration and walls without causing gouging.
in case of calcified and receded pulp chamber.
• Burs: (Fig. 13.23):
– For removal of caries, initial penetration and
deroofing the pulp chamber
- Round carbide burs (Medium sizes such as # 2,
# 4).
Fig. 13.23 Access preparation bur kit showing round bur, transmetal
bur, long shank round burs, safe-ended Endo Z bur and X-gates
(Courtesy of Dentsply)
Fig. 13.22 Magnifying loupe Figs 13.24A and B (A) Endo access bur; (B) Endo Z bur
(Courtesy of Dentsply)
Endodontic Access Cavity Preparation 207
– For enlarging the orifices and flaring of coronal WHICH ARE THE STEPS OF ACCESS
portion of the root canal and blending of the orifices CAVITY PREPARATION?
into the axial walls in order to gain straight-line
access (SLA), Gates Glidden burs can be used. Gates The general sequence of steps to be followed for access
Glidden drills/burs cut laterally in a selective manner cavity preparation are as follows:
so that excess removal of furcal dentin is avoided. Step 1: Removal of caries and existing restorations if any:
See Figure 13.16 for Gates Glidden drills -1 to 6 Penetration of enamel through lingual surface in
GG burs 1 to 6 and GG X: case of anterior teeth and through occlusal surface
GG 1 (ISO size # 50) in case of posterior teeth using the appropriate size
GG 2 (ISO size # 70) round bur, the size smaller than the size of the pulp
GG 3 (ISO size # 90) chamber of the tooth.
GG 4 (ISO size # 110) Figure 13.28 shows the diagram of initial entry
GG 5 (ISO size # 130) made through lingual surface in anterior tooth
GG 6 (ISO size # 150) perpendicular to the long axis of tooth.
GG X (Features of GG 1 to GG 4)
Figure 13.25 shows schematic representation of X
gates that has combined features of GG 1 to GG 4. It has
no ring on its shank. Figure 13.23 shows photograph of
X gates.
• Hand instruments:
– DG-16 Endodontic explorer: To locate root canal
orifices and to determine canal angulation
– Endodontic spoon excavator: To scoop out carious
dentin and to remove coronal pulp
Figure 13.26 shows diagrammatic representation
of DG 16 Endodontic explorer and Endodontic spoon
excavator.
• Ultrasonic unit and various ultrasonic tips: Can be useful
for exploring the root canal orifices by troughing and
deepening the developmental grooves to remove the
tissues with minimal collateral tooth structure removal. Fig. 13.27 Commercially available Endodontic ultrasonic tips—
Figure 13.27 shows commercially available Start X (Courtesy of Dentsply)
Endodontic ultrasonic tips.
Fig. 13.26 DG-16 Endodontic explorer and Fig. 13.28 Initial entry through the lingual surface in anterior teeth
Endodontic spoon excavator with the round bur perpendicular to the long axis of tooth
208 Short Textbook of Endodontics
In case of access through the crown, use of round the pulp remnants, dentinal mud and debris in
diamond bur for access through porcelain and suspension.
transmetal bur for access through metal. Figure 13.30 shows the withdrawal movement to
It is recommended to use a new sharp bur and deroof the pulp chamber.
cut the dentin in a light brushing motion to reduce In case of necrotic pulp, the pulp chamber be filled
the heat produced. with 5.25% warm sodium hypochlorite.
Step 2: Penetration of roof of pulp chamber: Keeping the bur Step 4: Axial wall extension: Is done at this step in order to
parallel to the long axis of the root all the time in case achieve a good convenience form. Tapered fissure
of anterior teeth and premolars as shown in Figure carbide or diamond bur with rounded end or safe-
13.29A. In case of molars, the penetration angle is ended diamond or carbide burs are used to funnel
towards the largest canal as shown in Figure 13.29B. the corners of the access cavity directly into the
A sudden sinking of the bur or “drop in” effect orifices and to plane the axial walls and slightly flare
is felt as soon as the roof of the pulp chamber is them towards the occlusal.
penetrated. But in case if the pulp chamber is deep or Figure 13.31 shows diagram demonstrating axial
calcified, such a feeling of drop may not be felt. So, it wall extension in maxillary molar.
is important to evaluate the preoperative radiograph
and measure the distance between the cusp tip and
the roof of the pulp chamber. The penetration should
be carefully limited to this distance.
Step 3: Complete removal of roof of the pulp chamber: Once
the pulp chamber roof has been penetrated, stop
pushing the bur, now withdrawal movement has to
be carried out in order to deroof the pulp chamber
completely. Brush cut against the roof as if lifting the
bur against the edge of the roof till the entire roof
is removed. This allows the internal pulp anatomy
to dictate the external outline form of the access
opening.
Ruddle recommends that in case of bleeding
vital pulp, at this step, the pulp chamber be filled
with viscous chelator such as EDTA to bring about Fig. 13.30 Deroofing the pulp chamber using round bur in
emulsification of vital pulp tissue and to hold withdrawal movement from inside of the pulp chamber to the outside
A B
Figs 13.29A and B (A) After penetration of enamel the bur is held Fig. 13.31 Axial wall extension in maxillary molar
along the long axis of the tooth till the pulp chamber is reached; (B) In
case of molars, the penetration angle is towards the largest canal
Endodontic Access Cavity Preparation 209
A B C D
Figs 13.34A to D Removal of internal triangle of dentin. (A) Mandibular molar in which access preparation is to be done; (B) Diagrammatic
representation of internal triangle of dentin hindering the straight line access; (C) Gates Glidden drill is used to remove the internal triangle
of dentin; (D) Straight-line access to the apical foramen after removal of internal triangle of dentin
• When there is SLA: There is better tactile Also, if the cavosurface margins are rough
sensation to feel the root canal anatomy and to and irregular, coronal leakage occurs through
feel how the file performs in root canal system. temporary or permanent restoration. Refinement
This allows all the areas of canal to be cleaned and smoothing of cavosurface margins helps
and shaped effectively. improve the coronal seal.
• When there is no SLA: Procedural errors such Figure 13.35 shows a mind-map to remember steps
as—ledge, transportation, zipping, instrument of access preparation.
separation, etc. can occur.
Step 9: Careful evaluation of the prepared access cavity:
Under good illumination and magnification using WHAT ARE THE SPECIFIC FEATURES OF ACCESS
dental operating microscope (DOM) and magnifying PREPARATION OF INDIVIDUAL TEETH AND
loupes, the access cavity should be inspected POSSIBLE ERRORS RELATED TO THEM?
carefully.
Additional canals may be located, that should then Maxillary Anterior Teeth
be cleaned and shaped.
After preparing the access cavity, when you view Steps of Endodontic access cavity preparation for maxillary
it using a mouth mirror, without moving the mouth anterior teeth are shown in Figures 13.36A to E.
mirror if all orifices can be visualized, then the access
cavity is said to be adequately prepared. If you have Maxillary Central Incisor
to move the mirror to view the orifices individually,
then it means that the access cavity is underprepared • External access outline form: Rounded triangle with
and you need to extend it further. incisal aspect forming the base of the triangle and the
Step 10: Refinement and smoothing the cavosurface margins: mesial and distal external walls converging towards
The access cavity preparation should have smooth, the cingulum as shown in Figure 13.37. The internal
diverging axial walls that allow smooth sliding down walls must funnel towards the root canal orifice. Since
of the instruments into the preflared orifices. the palatal surface is functional, a butt joint should be
After using GG drills, a surgical length tapered formed between the incisal internal wall and the lingual
diamond can be used to refine the access cavity. surface of the tooth to allow for the bulk of restoration.
212 Short Textbook of Endodontics
A B C D E
Figs 13.36A to E Access cavity preparation for maxillary anterior teeth. (A) Maxillary anterior tooth in which access is to be made; (B) Initial
entry made through the lingual surface with the round bur perpendicular to the long axis of tooth; (C) After penetration of enamel the bur
held along the long axis of the tooth till the pulp chamber is reached; (D) Complete removal of the roof of pulp chamber using round bur
working from inside to outside in withdrawal movement; (E) Removal of lingual shoulder using Gates Glidden
The orifice should be flared using small to large Maxillary Lateral Incisor
GG burs. These burs are used in circumference filling
motion, flaring each wall of canal in sequence. • External access outline form
Step 8: D etermination of straight-line access: Insert into – Rounded triangle as shown in Figure 13.38.
the canal the largest file that fits passively to the – Sometimes it is oval shaped when mesial and distal
apical foramen or the point of 1st canal curvature pulp horns are not prominent.
to evaluate the straight-line access. – Shape of a slender triangle when the pulp horns are
The file is inserted gently and withdrawn. If the file prominent.
binds or deflects, the adequacy of lingual shoulder • Stepwise procedure: Same as for the maxillary central
removal is re-evaluated. incisor.
Step 9 and 10: Refinement and smoothing of restorative • Variations: Crown can have lot of variations or
margins and careful evaluation of access preparation anatomic anomalies such as gemination, fusion with a
The cavosurface margins should be refined and supernumerary tooth, dens invaginatus, etc.
smoothened in order to place and finish the final • Possible errors:
restoration with precision that is necessary to – Failure to remove lingual shoulder
minimize coronal leakage. – Gouging due to improper inclination of bur
Using appropriate magnification devices, the – Perforations
completed access preparation is evaluated. It should • Important considerations:
be smooth, funnel-shaped and continuous with the – An important anatomic feature of this tooth that
radicular portion of pulp cavity. Also it must provide should be considered is that most of the times,
straight-line access to the apical third of root canal. the root typically curves to the distal although
• Variations: The access cavity preparation is sometimes it may be straight.
designed to be more oval shaped in outline in – This tooth is known to have many anomalies that
mature teeth due to receded pulp horns. may cause difficulty in treatment.
• Possible errors:
– Too far gingival extension of access Maxillary Canine
preparation
– Failure to remove the lingual shoulder • External access outline form: Oval or slot shaped due to
– Gouging due to improper alignment of bur absence of mesial and distal pulp horns. Figure 13.39
– Perforations shows the external access outline form of a maxillary
– Inadequate incisal extension causing failure canine.
to remove the tissue from the pulp horns • Stepwise procedure: Technique is same for the maxillary
that causes discoloration of the tooth after central and lateral incisors. Since this tooth is heavily
treatment. involved in excursive movements and occlusal function,
Fig. 13.38 Access cavity outline form of maxillary Fig. 13.39 Access cavity outline form of maxillary
lateral incisor (palatal surface), (D, Distal; M, Mesial) canine (palatal surface), (D, Distal; M, Mesial)
Endodontic Access Cavity Preparation 215
a butt joint relation is required between the incisal Maxillary Premolar Teeth
wall and the lingual surface of the crown for adequate
thickness of restorative material. Steps of Endodontic access cavity preparation for maxillary
• Variations: Usually has single canal but in some cases premolar teeth are shown in Figures 13.40A to F.
two canals have been reported.
• Possible errors: Maxillary First Premolar
– Gouging due to improper inclination of bur
– Failure to remove the lingual shoulder • External access outline form: Oval or slot shaped that
– Perforations. runs in buccolingual direction with buccal extension
A B C
D E F
Figs 13.40A to F Access cavity preparation for maxillary premolar teeth. Endodontic preparation in maxillary premolar. (A) Initial entry
made parallel to the long axis of tooth through occlusal surface in the central groove of maxillary premolar using a round or small tapered
fissure bur in an accelerated speed contra-angle handpiece; (B) No. 2 or No. 4 round bur is used to penetrate into the pulp chamber; (C) An
Endodontic explorer used to locate the canal orifices; (D) Deroofing the pulp chamber using round bur working from inside the pulp chamber
to outside; (E) Buccolingual extension and finishing of cavity walls using tapered fissure bur; (F) Final preparation should allow straight-line
access of Endodontic instrument to the apex
216 Short Textbook of Endodontics
When two canals are present, the access preparation Maxillary Molar Teeth
is identical to maxillary first premolar with the difference Steps of Endodontic access cavity preparation of maxillary
that only single root is present and the canals are not molar teeth are shown in Figures 13.43A to G.
A B C
D E F G
Figs 13.43A to G Access cavity preparation for maxillary molars. (A) Buccal view of maxillary molar in which access cavity is to be
prepared; (B) Proximal view of same tooth; (C) Initial entry through occlusal surface using round bur in the exact center of mesial pit;
(D) Endodontic explorer is used to locate the canal orifices; (E) Deroofing the pulp chamber using round bur in withdrawal movements from
inside of pulp chamber to outside; (F) Final finishing and funnelling of cavity walls; (G) Final preparation should allow unobstructed access
to all the orifices
218 Short Textbook of Endodontics
Figures 13.45A and B show clinical photo • Variations: Additional root canals such as second palatal
graphs of access cavity preparation of maxillary canal or second canal in mesiobuccal root have been
first molar with four canals in two cases. reported.
• Possible errors: – Possible errors:
– Underextended preparation merely exposing the - Under extended preparation merely exposing the
pulp horns mistaken for root canal orifices. pulp horns mistaken for root canal orifices.
– Gouging in an attempt to search for orifices in a tooth - Gouging in an attempt to search for orifices in a
with receded pulp chamber. tooth with receded pulp chamber.
– Furcal perforation due to failure to recognize the - Furcal perforation due to failure to recognize the
depth of pulp chamber. depth of pulp chamber.
– Lateral perforation due to improper bur angulation. - Lateral perforation due to improper bur
– Failure to recognize the canal curvatures causing angulation.
further procedural errors such as ledging, perforation. - Failure to recognize the canal curvatures causing
further procedural errors such as ledging,
Maxillary Second Molar perforation.
• External access outline form: When two canals are
present, it is oval shaped extending buccolingually. Maxillary Third Molar
When three canals are present, it is rounded triangle
which is more obtuse due to position of distobuccal Root canal anatomy of this tooth is unpredictable and lot
orifice being quite closer to a line connecting the of variations are possible. Access cavity preparation will
mesiobuccal and palatal orifices as shown in Figure vary as per the number of roots and root canals and other
13.46. anatomic variations. About one to four roots and one to six
When four canals are present, it is rhomboid shaped. canals are possible. Most of the times the roots are fused to
• Stepwise procedure: Similar to maxillary first molar with form a single large root.
some differences such as all orifices are located more Figure 13.47 shows the access cavity preparation in
closer mesially than in first molar. maxillary third molar with three canals.
Fig. 13.46 Access cavity outline form of maxillary second molar with Fig. 13.47 Access cavity preparation of maxillary third molar with
three, two and one canal respectively (occlusal view), (B, Buccal; D, three canals, (B, Buccal; D, Distal; M, Mesial; L, Lingual)
Distal; M, Mesial; L, Lingual)
220 Short Textbook of Endodontics
A B C D
E F G H
Figs 13.48A to H Access cavity preparation for mandibular anterior teeth (A) Initial entry made through lingual surface in the exact center
using a tapered fissure bur in accelerated speed contra-angle handpiece perpendicular to long axis of tooth; (B) Round bur No. 2 to penetrate
into pulp chamber; (C) Round bur used to deroof the pulp chamber working from inside the pulp chamber to outside; (D) Removal of lingual
shoulder and finishing the cavity walls; (E) Final preparation should allow unobstructed straight-line access of Endodontic instrument to the
apex; (F) Inadequate access opening can let the pulp tissue remnants to remain the coronal part of the tooth leading to discoloration later;
(G) Failure to remove the lingual shoulder will lead to missed lingual canal causing Endodontic failure; (H) Correct extension after removal of
lingual shoulder causing straight-line access of Endodontic instrument in both the canals
• Stepwise procedure: Technique is similar to that of 40% of mandibular incisors have two canals—buccal
maxillary central incisor. and lingual.
The initial entry point is just above the cingulum It is not necessary to have butt joint junctions
with the bur held perpendicular to the entry point. between the internal walls and the lingual surface
Remove the lingual shoulder completely as this tooth because lingual surface of the tooth is not involved in
often has two canals that are buccolingually oriented occlusal function.
and the lingual canal most often gets missed. About
Endodontic Access Cavity Preparation 221
A B
Figs 13.49A and B Access cavity outline form of mandibular central Fig. 13.50 Access cavity outline form of mandibular canine (incisal
incisor with one canal and mandibular lateral incisor with two view) with one and two canals, (B, Buccal; D, Distal; M, Mesial;
canals, (D, Distal; M, Mesial) L, Lingual)
• Possible errors: larger and its cusp tip is inclined lingually, so the access
– Extension too far gingivally. preparation lies more to the mesial of the midpoint
– Failure to remove the lingual shoulder that mostly mesiodistally.
causes missed lingual canal. Figure 13.50 shows the access outline form of
– Gouging due to improper bur angulation and failure mandibular canine (incisal view).
to recognize the linguoaxial or mesioaxial angulation • Stepwise procedure: Technique is similar to Maxillary
of tooth. canine. The lingual shoulder must be removed to gain
– Inadequate incisal extension causing failure access to the lingual wall of the root canal or to the
to completely remove the pulp debris causing entrance of a second canal. Buccal wall is larger and the
discoloration of tooth after treatment as shown in lingual wall is slit-like. As a result, cleaning and shaping
Figure 13.48F. may be difficult.
Like the mandibular incisors, butt joint junctions are
Mandibular Lateral Incisor not necessary.
• Possible errors:
• External access outline form: Triangular or oval – Extension too far gingivally
shaped which is longer incisogingivally and narrower – Failure to remove the lingual shoulder that mostly
mesiodistally. causes missed lingual canal
Figure 13.49B shows the access outline form of – Gouging due to improper bur angulation and failure
mandibular lateral incisor with two canals from incisal to recognize the linguoaxial or mesioaxial angulation
view. of tooth.
• Stepwise procedure: Same as mandibular central incisor – Inadequate incisal extension causing failure
• Possible errors: to completely remove the pulp debris causing
– Extension too far gingivally. discoloration of tooth after treatment.
– Failure to remove the lingual shoulder that mostly
causes missed lingual canal. Mandibular Premolar Teeth
– Gouging due to improper bur angulation and failure
to recognize the linguoaxial or mesioaxial angulation Steps of Endodontic access cavity preparation of mandibular
of tooth. premolar teeth are shown in Figures 13.51A to E.
– Inadequate incisal extension causing failure
to complet ely remove the pulp debris causing Mandibular First Premolar
discoloration of tooth after treatment.
• External access outline form: Oval shaped as shown in
Mandibular Canine Figure 13.52.
• External access outline form: Oval or slot-shaped narrow • Stepwise procedure: The procedure is the same as for
mesiodistally and wider buccolingually. Its incisal the maxillary premolars. But some specific points for
extension is towards the incisal edge and gingival mandibular first premolar are:
extension penetrates the cingulum. Mandibular canine – Usually the initial entry is made at the upper third
has almost straight mesial edge, its distal surface is of lingual incline of the facial cusp with #2 round
222 Short Textbook of Endodontics
A B C D E
Figs 13.51A to E Access cavity preparation of mandibular premolars: (A) Initial entry through occlusal surface in the central groove of
mandibular premolar; (B) Round bur used to penetrate into the pulp chamber; (C) Endodontic explorer used to locate canal orifice; (D) After
deroofing of pulp chamber, tapered fissure bur used for buccolingual extension and finishing of cavity walls; (E) Final preparation should
allow straight line access of Endodontic instrument to the apex
• Possible errors:
– Perforation due to improper bur angulation or due
to failure to recognize the tilt of premolar
– Inadequate extension causing further preparation
errors
– Apical perforation due to overinstrumentation or
due to failure to recognize the buccal or lingual apical
curvature.
Fig. 13.53 Access cavity outline form of mandibular second
premolar (occlusal view), (B, Buccal; D, Distal; M, Mesial; L, Lingual) Mandibular Molar Teeth
Steps of Endodontic access cavity preparation of mandibular
– Lingual half of the tooth is more fully developed, so molar teeth are shown in Figures 13.54A to G.
lingually access preparation may extend halfway up
the lingual cusp incline.
A B C D
E F G
Figs 13.54A to G Access cavity preparation of mandibular molars. (A) Buccal view of mandibular molar in which access is to be prepared;
(B) Proximal view of same tooth; (C) Initial entry made using round bur through the occlusal surface in the exact center of the mesial pit;
(D) Endodontic explorer is used to locate the canal orifices; (E) Round bur is used from inside to outside of the pulp chamber for deroofing
of the pulp chamber; (F) Final finishing and funnelling of access cavity walls; (G) Final access preparation should allow unobstructed access
to the canal orifices
224 Short Textbook of Endodontics
Fig. 13.56 Clinical photograph of access cavity preparation in Fig. 13.57 Clinical photograph of access opening in mandibular first
mandibular molar with four canals seen under microscope (Courtesy molar with three canals (Additional middle mesial canal) (Courtesy
of Dr Roheet Khatavkar) of Dr Shivani Bhatt)
A B
Fig. 13.60 Access cavity preparation in mandibular third molar
with three canals, (B, Buccal; D, Distal; M, Mesial; L, Lingual)
A B C
Figs 13.61A to C (A) Radiograph showing calcified canal in maxillary left central incisor tooth, in which overzealous attempt to locate
canal has removed large amount of sound dentin; (B) With the use of dental operating microscope (DOM) and adequate light, the root
canal was located and negotiated, cleaned and shaped and obturation completed; (C) Access cavity opening sealed with a restoration
(Courtesy of Dr Roheet Khatavkar)
• Safe approach to face the challenge: – Excessive gouging of coronal or radicular tooth
– Careful reading of preoperative radiographs to structure in search of orifice of canal in a wrong
recognize such complexities direction.
– Careful negotiation and instrumentation of such root • Safe approach to face the challenge:
canals keeping in mind the complex anatomy. – Determine the anatomic relationship of the crown
to root by taking angled diagnostic periapical
Teeth with Minimal Coronal Tooth Structure radiographs
– Visualize and determine if there are any likely
• Challenge: To conserve as much sound tooth structure variations that have to be made during access cavity
as possible to protect it from fracture. preparation.
– Crown to root relation may not be identified due to
inadequate coronal tooth structure. Access Through Full Veneer Crowns
• Possible errors: Coronal or root perforation may occur
as a result of loss of significant coronal anatomy. • Challenge: If the full veneer crown has to be retained,
• Safe approach to face the challenge: making access cavity preparation through it is a
– Careful study of preoperative radiographs to study challenge.
the root angulation • Possible errors:
– Careful probing of the cervical crown anatomy with – If you are conservative during access cavity
an explorer preparation, preparation may be underextended
– Palpate the root eminences causing various procedural errors.
– Start access before placing rubber dam in such – Failure to recognize crown to root angulation may
cases result in perforation.
– If the canal is not located till a greater depth, then – Leakage or recurrent caries may be left unattended
instead of attempting to search the orifices, take to resulting in failures later.
radiographs at various angles before proceeding. • Safe approach to face the challenge:
– When you prepare access through the full veneer
Crowded Teeth crown, do it with caution.
– Check the root prominence.
• Challenge: To obtain straight-line access while – Identify the long axis of the tooth.
conservation of tooth structure and without compro – Carefully evaluate preoperative radiographs to find if
mising esthetics is the challenge. the full veneer crown has been altered. For example,
• Possible errors: rotated tooth may have the full veneer crown that is
– Inadequate access leading to inadequate cleaning in the correct position and not in rotated position.
and shaping, missed canals, etc. – Also, evaluate from preoperative radiograph, the
– Failure to achieve straight-line access (SLA) causing mesial/distal or axial inclination of the involved
further procedural errors tooth and its parallelism to the adjacent teeth.
• Safe approach to face the challenge: – Check for the orientation of adjacent teeth clinically.
– Such cases may require an alternative approach of – Dental operating microscope (D OM) and
access preparation transillumination of CEJ can be a valuable aid.
– Sometimes buccal access preparation will have to – When some doubt exists that the underlying tooth
be made to achieve SLA. may be rotated, drill through the center of the full
veneer crown for a safe access.
Rotated Teeth Table 13.1 shows the summary of the challenging
access preparations.
• Challenge: To visualize the anatomic crown-to-root
relationship before making access preparation in order WHAT ERRORS CAN OCCUR DURING ACCESS
to correctly angulate the bur with respect to the long axis
CAVITY PREPARATION?
of root is the challenge.
• Possible errors: Errors may occur in access cavity preparation if:
– Perforations during access preparation • There is clinician’s lack of understanding of the internal
– Missed canals or external morphology of tooth or
Endodontic Access Cavity Preparation 229
hence compromise the final restoration and longevity (Discussed in detail in Chapter 20 Endodontic Mishaps:
of the treated tooth. Management and Prevention).
• Overzealous tooth removal: Gouging Figure 13.63 shows a mind-map to remember the errors
Improper bur angulation and failure to recognize in access cavity preparation.
the inclination of tooth can result in overzealous tooth
removal. This results in weakening and mutilation of BIBLIOGRAPHY
tooth structure predisposing it to fracture.
These have been discussed in detail in Chapter 20 1. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis:
Mosby. 2006.pp.165-228.
Endodontic Mishaps: Management and Prevention. 2. Grossman L, Oliet S, Del Rio C. Endodontic Practice, 11th edn.
Varghese publication. 1991.pp.151-77, 79.
Perforations 3. Ingle J, Bakland L, Baumgartner J, Ingle’s Endodontics, 6th edn.
BC Decker Inc, Hamilton. 2008.pp.877-918.
Results in communication between root canal system and 4. Ingle, Bakland, Endodontics, 5th edn. Plates 3 to 27, BC Decker-
the periodontal tissues. Elsevier. 2002.
Cleaning and Shaping of
the Root Canal System
14
CHAPTER
This chapter describes the objectives and the various concepts and strategies for effective root canal
preparation and discusses in detail the root canal preparation techniques.
You must know
• What is Cleaning and Shaping of Root Canals?
• What are the Objectives of Cleaning and Shaping of Root Canals?
• Which are the Important Numerical Concepts in Root Canal Preparation and how to
Determine Them?
• What are the Current Concepts and Terminology for Root Canal Preparation?
• Which are the Different Instrument Motions for Effective Shaping of Root Canals?
• What are the Requirements before Starting Canal Preparation?
• Which are the Different Canal Preparation Techniques?
• What are the Precautions to be taken during Instrumentation?
• What are the Procedural Errors that can Occur during Root Canal Preparation?
Without irrigation, mechanical instrumentation • Prepare a sound apical dentin matrix at the cemento-
becomes ineffective rapidly due to accumulation of dentinal junction (CDJ) for apical seal.
debris. Without enlarging and shaping, the irrigating • Design the preparation such that the cross-sectional
solutions cannot reach all parts of the root canal system. diameter becomes narrower at every point apically.
Shaping removes restrictive dentin thereby improving • Avoid preparation errors such as zipping, perforations,
the effectiveness and the control of canal preparation and etc.
allows irrigation solution to completely penetrate the root
canal system. Thus, shaping facilitates cleaning and cleaning Clinical objectives:
facilitates shaping. • To remove restrictive dentin in order to
Also only well-shaped canals can be filled in three – Improve effectiveness and control of canal
dimensions. Thus, shaping facilitates 3-D obturation. preparation,
Various instrumentation and shaping techniques will – Allow irrigation solution to completely penetrate the
be discussed in this chapter. Various chemical agents used root canal system (Shaping facilitates cleaning).
for effective cleaning will be discussed in the next chapter • To remove the accumulated debris created by mechanical
(Chapter 15). instrumentation by means of root canal irrigation for
effective shaping (Cleaning facilitates shaping).
WHAT ARE THE OBJECTIVES OF CLEANING AND • To develop a logical cavity preparation specific for the
anatomy.
SHAPING OF ROOT CANALS?
• To allow for three-dimensional filling of well-shaped and
Biologic objectives are to: cleaned root canals (Cleaning and shaping facilitates
• Remove pulp tissue remnants and infected dentin from three-dimensional obturation of the root canal system).
the root canal system. Figure 14.1 shows the mind-map to remember all
• Remove bacteria and their endotoxins and all potential objectives of cleaning and shaping.
irritants from the entire canal system.
• Confine all instrumentation procedures within the root
canal space.
• Avoid pushing contaminated debris beyond the apical
foramina.
• Create sufficient space within the canal for irrigation
and intracanal medicaments (Remember biologic
objectives-CCARR).
Mechanical objectives:
(Remember these mechanical objectives with the help of
following sentence: Kindly Prepare Design Mechanically
with Anatomy Maintained and Less Disturbed.)
• Develop a smooth continuously tapering funnel-shaped
preparation in all three-dimensions such that the cross-
sectional diameter of the canal narrows towards the
foramen.
• Maintain the original root canal anatomy by fully
incorporating all walls of canals into prepared shape
such that the preparation flows with the shape of the
original canal.
• Maintain the original position of apical foramen.
• Keep the apical opening as small as practically possible.
• Leave as much radicular dentin as possible to prevent
weakening of root structure. Fig. 14.1 Mind-map of objectives of cleaning and shaping
Cleaning and Shaping of the Root Canal System Including Working Length Determination 233
Working Length
Canal length is the distance from a coronal reference point
to the apical exit of the root canal.
Anatomic apex of the root is the tip or end of the root
which is morphologically determined.
Radiographic apex of the root is the tip or end of the root
which is determined on the radiograph.
The radiographic apex may be different from the
anatomic apex due to variations in the morphology of the
root and factors related to the radiographic technique. A B
Method for Determination of Working Length clinician especially when the coronal portion has been
• The process of determination of the current working adequately enlarged.
length (WL) is called Endometrics. This method requires that the canal is preflared prior to
• Requirements for the ideal method of accurate working determining the working length.
length determination: Ingle 6th edition has given The tactile method can be used as a supplementary
following requirements: method with other methods for working length
– The method should allow location of apical determination but cannot be used alone because it has
constriction rapidly (Quick) high chances of giving inaccurate measurements in case
– The method should provide accurate readings in all of excessively constricted and curved canals. It is also an
conditions of pulp and in the presence of all canal inaccurate method in root canals with an immature apex.
contents
– The method should provide easy measurement Evaluation of Patient’s Response to a File Introduced in
– The method should allow for confirmation and
the Canal (Apical Periodontal Sensitivity)
periodic monitoring of working length
– The method should be comfortable to both the This is not a method for working length determination per se,
patient and the clinician but a file introduced beyond the apical constriction causes
– The method should cause minimal radiation to painful response, which gives an indication that the WL
patient would be approximately lesser than this length to which the
– The method should be easy to use even in specific file was introduced. This, however, can be misleading when
condition of patient such as severe gag reflex, limited a file is advanced in a canal with inflamed tissue may cause
opening of mouth and pregnancy pain even when instrument tip is short of apical constriction.
– The method should be economical.
Since no single method satisfies all requirements, Evaluation of Paper Point Placed in the Canal
combination of several methods should be used for accurate
working length determination. In this method, the blunt end of the paper point is gently
• Various methods for working length determination: inserted in the canal to the extent it can penetrate after
1. Digital tactile sense profound anesthesia. The moisture or blood on the apical
2. Evaluation of patient’s response to a file introduced portion of the paper point gives an estimation of WL.
into the canal (Apical periodontal sensitivity) This method is also a supplementary method to aid in
3. Evaluation of paper point placed in the canal working length determination.
4. Use of mathematical formula (Grossman’s method) It is useful in canals with immature root apex and in
5. Use of radiographs cases of apical resorption or perforation where the moisture
Different radiographic methods: or blood determines the amount of overextension.
a. Grossman’s method
b. Ingle’s method Use of Mathematical Formula
c. Weine’s method
d. Kuttler’s method • Grossman’s formula
e. Radiographic grid KLI × ALT
f. Endometric probe Correct Length of Tooth (CLT) = __________________
g. Direct digital radiography ALI
h. Xeroradiography Where, KLI = Known length of instrument or the pre
i. Subtraction radiography measured length
6. Use of electronic apex locators. ALT = Approximate length of tooth from
Currently, the widely used method for working length radiograph
determination is the combination of use of electronic apex ALI = Approximate length of instrument from
locators and the radiographs. radiograph
In this method, a premeasured file is placed in the canal
Digital Tactile Sense and a radiograph is taken and then using the above formula,
the working length is determined.
Resistance is felt as the file approaches the apical 2–3 mm, Methods requiring formula for working length
which can be detected by tactile sense by an experienced determination have been abandoned. Bramante and
Cleaning and Shaping of the Root Canal System Including Working Length Determination 235
Use of Radiographs
Requirements
• For determination of working length, the radiographs
taken should be of good quality and undistorted.
• Reference points: The anatomical landmark on tooth used
as coronal reference point should be reproducible. So,
the cusps which are weakened by caries or restoration
may have to be reduced to a flat surface as shown in
Figures 14.4A and B in order to have a stable reference
plane and thus preventing the possibility of loss of A B
reference point due to fracture of weak enamel or cusps
in between appointments. Figs 14.6A and B Instrument stop should be placed perpendicular
• Exploring instrument: In this method, an appropriate to the reference plane: (A) Incorrect placement of instrument stop;
(B) Correct placement of instrument stop
size K-file with an instrument stop is used as exploring
instrument to determine the working length.
Smaller fine instruments such as #8 and #10 K-files when
used as exploring instruments may be quite loose in Figure 14.5 shows the photograph of an Endoblock.
the canals and may cause errors in WL and also their • Instrument stops should be properly placed on the shaft
tips are sometimes not clearly visible on radiographs. of the exploring instrument such that it lies perpendicular
So, an instrument size which is not very small but can to the shaft as shown in Figure 14.6B. Instrument stops
negotiate the entire length of root canal should be used made of different materials such as metal, plastic and
as exploring instrument such as no.15 K-file. silicone rubber are available. Teardrop-shaped silicone
• A scale or an Endodontic millimeter ruler such as a rubber stops help in the orientation of instrument into
calibrated “Endoblock’ is used to adjust the instrument canal curvatures and they need to be removed from the
stop. instrument during sterilization.
236 Short Textbook of Endodontics
Fig. 14.7 Measurement of approximate tooth length Fig. 14.8 Deducting 1 mm and determining
from a preoperative radiograph tentative working length
than this length is placed in the canal and a radiograph Direct digital radiography (RadioVisuo Graphy and
is taken to determine the working length. Phosphor Imaging System), Xeroradiography and
c. Weine’s method: It makes use of radiographs for working Subtraction radiography are the advanced radiographic
length determination and Weine has recommended the methods for determining the working length, with
following apical termination points: digital radiography being quite common and widely
– If no bone or root resorption—1 mm from apex used these days. These methods have been described
– If only bone resorption—1.5 mm from apex in detail in Chapter 7 Diagnosis and Diagnostic Aids in
– If both bone and root resorption—2 mm from apex Endodontics.
d. Kuttler’s method: According to studies done by Kuttler,
the root canal preparation should terminate at apical Use of Electronic Apex Locators
constriction, i.e. minor diameter.
The average distance between the major and minor Radiographs enable us to arbitarily work around the apical
diameter: constriction. To overcome this limitation, an electronic
– Young patients—0.524 mm device called apex locator was introduced that helps to
– Older patients—0.659 mm accurately determine the position of apical constriction
Step-wise procedure: or the Cemento-Dentinal Junction (CDJ) and not the
i. Locate major and minor diameter on the pre- radiographic apex (The term apex locator is a misnomer).
operative radiograph. Apex locators are electrical devices that determine the
ii. Estimate length of the roots from preoperative working length and give the measurement by means of
radiograph using a millimeter scale. some ‘sound’ or ‘movement of a dial’ or ‘indicator’ when
iii. Estimate width of root canal on the preoperative the correct position is reached.
radiograph using #10 or #15 K-file for narrow canal, Figure 14.10 shows the photograph of commercially
#20 or #25 K-file for average width and #30 or #35 available apex locator.
K-file for wide canals.
iv. Insert the selected K-file in the root canal to the Principle: Apex locator compares the electrical resistance
estimated canal length and take a radiograph. of periodontal membrane with that of gingiva surrounding
v. On radiograph: the tooth, both of which should be similar.
- If file appears too long or short by more than Difference in impedance is found between high and low
1 mm from the minor diameter, then readjust frequencies at various sites in the root canal.
the instrument accordingly and take another Difference between two frequencies is less in coronal
radiograph to confirm. portion of canal.
- If file appears reaching the major diameter,
subtract 0.5 mm from that length in young
patients and subtract 0.67 mm in case of older
patients.
vi. Advantages of this method: It is quite accurate
with minimal errors and has resulted in many
successful cases.
vii. Disadvantages of this method: It is complicated
method and requires excellent quality radio
graphs.
e. Radiographic grid: This method involves superimposing
a millimeter grid on the radiograph, making it simpler to
estimate the working length with no need for calculation.
But if the radiograph is bent, it may not give the correct
length.
f. Endometric probe: This method uses the graduations
on diagnostic file which are visible on the radiograph.
Endometric probe is etched at millimeter increment. The
disadvantage of this method is that the smallest size of Fig. 14.10 Commercially available apex locator
file used is number 25. (Courtesy of Dentsply)
238 Short Textbook of Endodontics
Difference between two frequencies increases in deeper A mind-map to remember all points of working length
portion of canal. is given in Figure 14.11.
Difference between two frequencies is highest at
Cemento-Dentinal Junction (CDJ). Working Width/Apical Width/Apical Preparation
Generations of apex locator: These have been discussed
One of the objectives of radicular preparation is to keep the
in detail in Chapter 11: Endodontic Armamentarium:
apical opening as small as practically possible.
Instruments, Materials and Devices.
Whether the apical width should be kept narrow or wide
Components of apex locator: Discussed in Chapter 11. is a matter of debate with advantages and disadvantages of
either of them. The aim is to reduce the intracanal microbial
Factors determining accuracy of apex locators: Discussed
load as much as possible by preparing the apical canal
in Chapter 11.
areas so as to facilitate optimal irrigation and antimicrobial
Method: Generally a no. 15 K-file is used in the root canal activity.
held on the file clip to estimate the length since it gives ‘Apical width’ or ‘Working width’ is the term used for
apex locator readings efficiently and its tip well seen on the the size of the preparation to which the apical portion of
radiograph taken to confirm the position of the file within the canal should be enlarged—Apical preparation.
a root canal. Smaller files like no. 6, 8, 10 may not be well- Apical scouting is the process of determining the
appreciated on radiograph and may be loosely fitting in anatomy and cross-sectional diameter of the apical 1/3rd
the root canal. of the root canal, based on which the final size to which the
preparation should be enlarged, is estimated.
Advantages Ruddle has suggested passing a series of K-files to
• It precisely locates the position of apical constriction. working length to gauge the apical width.
(Accuracy up to 90% or more). Grossman had recommended to enlarge a root canal
• Reduction of radiation exposure by eliminating the need to three sizes more than the first instrument that binds
for multiple radiographs. One radiograph may be taken in the root canal or to enlarge it till all infected dentin is
to confirm the readings given by apex locator. removed and clean, white dentinal shavings appear on
• Eliminates errors associated with radiographic image flutes of the working instrument blade. However, these
distortion. recommendations are no longer considered optimum for
• Easy and quick method. determining the apical width.
• It is useful in verifying perforations, bifurcations of root
Factors to be considered to determine apical width: Size of
and any obstructions.
preparation of the apical portion varies from case to case
• It is very useful in maxillary molar teeth, where radio
and can be determined by considering following factors as
graphs may be difficult to read accurately due to
given in Figure 14.12.
radiopaque structures such as malar process and floor
of maxillary sinus.
• Useful in patients with gag reflex and in children who Advantages and Disadvantages
cannot tolerate placement of X-ray film and also a • Wider apical preparation:
valuable tool in case of pregnant patients in whom the – Advantages:
radiation exposure should be avoided. - Ensures that all of the infected dentin has been
removed.
Disadvantages - Provides access to irrigating solutions and allows
• Some of the earlier generation apex locators do not give placement of intracanal medicaments in the
accurate readings in presence of canal contents. apical portion to reduce the microbial load.
• Erroneous readings are obtained in case where current – Disadvantages:
flows into marginal gingiva or into metal restorations. - There is risk of errors in an attempt to make the
• Inaccurate readings in case of low battery, blockage of apical preparation wider such as:
canal and in too wet or too dry canal. ■ Apical perforation
• There can be difficulty in estimation of length in cases ■ Apical transportation
with wide open apex such as immature teeth. ■ Overinstrumentation
• Cannot be used in patients with cardiac pacemakers. ■ Extrusion of irrigants and medicaments peri
This problem has been overcome in newer generation apically
apex locators. ■ Overextension of obturating material
Cleaning and Shaping of the Root Canal System Including Working Length Determination 239
Taper
Taper of the preparation is brought about by the taper of the
instruments used for shaping of the root canal.
Earlier, stainless steel hand instruments that were used
had a constant taper of 2% (0.02) throughout the length
Fig. 14.12 Mind-map showing factors determining
apical width of root canal
of the instrument as per the ISO standards. Currently,
instruments with greater tapers such as 4%, 6%, 8%, 10%,
12% have also become available made of Nickel-titanium.
Patency File
Patency file is a small K-file (such as size #10) which is
passively just pushed through the apical foramen to the
radiographic terminus without causing its enlargement as
shown in Figure 14.17.
The concept of using patency file is controversial.
• Points in favor of using patency file:
– Patency file cleans the apical foramen
Fig. 14.17 Patency filing with no. 10 K-file
– It prevents packing of debris in the apical portion of
the canal
– It helps to maintain working length by removal of
accumulated dentinal debris and shavings produced Apical Clearing
as a result of instrumentation
– It does not cause any apical enlargement. Process of removal of loose debris from the apical extent
• Points against using patency file: of the root canal by using two to four successively larger
– It might push contaminated debris periapically instruments than the initial apical file at the working length.
through the apical foramen. After final irrigation and drying, the last instrument is
– It may mechanically injure the periapical tissues. once again worked in the canal called as master apical file
– It may inoculate microorganisms periapically. for the purpose of apical clearing.
Cleaning and Shaping of the Root Canal System Including Working Length Determination 243
Fig. 14.18 Push-pull motion Fig. 14.19 Reaming motion: Penetration, rotation and retraction
WHAT ARE THE DIFFERENT INSTRUMENT • Reaming motion involving one-half turn before
MOTIONS FOR EFFECTIVE SHAPING withdrawal can be used for preparing straight canals
OF ROOT CANALS? and that involving one-quarter turn before withdrawal
can be used for slightly curved canals.
Filing Motion (Fig. 14.18) • Reaming produces round, tapered preparation.
• Reamers are used in reaming motion. Files can also be
• Filing motion is penetration and withdrawal, where the used in reaming motion.
primary cutting action occurs on withdrawal. • Chances of apical transportation are less with reaming
Also called as push-pull motion or rasping motion. motion.
• The instrument is to be placed into the canal till
appropriate length and pressure is exerted against the Watch-winding Motion
wall of the canal. While maintaining pressure, the file is
withdrawn from the canal. • It is back and forth oscillation motion of instrument as
• The filing motion is carried out circumferentially to file it is advanced without applying any apical pressure.
all walls of the canal. • This motion involves a quarter turn rotation using
• K-files are commonly used in filing motion. Hedstrom smaller size files such as #8 or #10.
files bring about very effective filing motion. • It is most desirable during the initial phases of root canal
• Chances of apical transportation are more with filing preparation before coronal flaring is done.
motion. • The instrument is inserted to explore the canal with this
motion.
Reaming Motion (Fig. 14.19) • There are less chances of preparation errors with this
motion.
• Reaming motion is penetration, rotation and retraction,
cutting action occurs on retraction. Rotary Motion
• The instrument is inserted in the canal till appropriate
length and twisted clockwise one-quarter to one-half • Continuous rotary movement with Nickel-Titanium
turn so that the instrument blades are engaged into the rotary files is now the most commonly used motion for
dentin and then the instrument is withdrawn. root canal preparation.
244 Short Textbook of Endodontics
Fig. 14.21B Circumferential filing in apical third. Irrigation Fig. 14.22 Irrigation is done using a side-vented needle
between each instrument use is a must
walls of the canal with irrigation in between taper from the apical constriction to the
instrumentation and recapitulation with cervical canal orifice as shown in Figure
smaller instruments periodically. 14.25.
Purpose of recapitulation:
i. Prevent blocking with dentinal debris The step-back method aims at providing the final
ii. Permit insertion of larger instruments to preparation as an exact replica of the original canal
the working length configuration, shape and taper, but only of larger size.
iii. Smoothen the walls of the canal • An example illustrating the step-back technique for
■ The last file that was used for apical instrumentation:
preparation called the master apical file is A straight root canal with working length determined as
reinserted to the working length to maintain 20 mm.
the patency of the apical segment.
■ Body of the canal is instrumented with three Working length (WL) adjusted to: Size of file
or four larger files in sequence with periodic • 20 mm # 10, # 15, # 20, # 25
recapitulation in between and copious • 19 mm (WL minus 1 mm) Use of # 20 for recapitulation
irrigation with sodium hypochlorite after (i.e. 1 mm short of apical foramen) # 30, # 35, # 40
• 18 mm (WL minus 2 mm) Use of # 30 for recapitulation
each instrument use.
(i.e. 2 mm short of apical foramen # 45, # 50, # 55
Figure 14.23 demonstrates the preparation of Use of # 50 for recapitulation
apical third and body of canal.
- Preparation of coronal portion of canal (Phase B. Curved root canals and other anatomic variations
II A): causing difficulty
■ Gates Glidden (GG) drills or Hedstrom files, – Modifications for root canals with gentle curvature:
one or two sizes larger than the previous - The instrument blade should be precurved as
instruments used in canal can be carefully per the curvature and a directional silicone
used to flare the coronal portion of root canal instrument stop should be positioned such that it
as shown in Figure 14.24. indicates the direction in which the file has been
- Refining phase of preparation (Phase II B): curved.
■ It involves use of master apical file to - Smaller K-files used in apical portion of root
smoothen all the walls and get a continuous canal are flexible and can be precurved easily
Cleaning and Shaping of the Root Canal System Including Working Length Determination 247
Fig. 14.23 Serial root canal preparation of apical third and body of canal
Fig. 14.24 Gates Glidden (GG) drill for coronal flaring Fig. 14.25 Master apical file used for refining phase of preparation
but for larger inflexible files a diamond file or – Instrument tip of a smaller file is modified by cutting
sandpaper disc is used to dull the flutes of the about 1 mm from the end and smoothening it with a
outer portion of the curve in apical segment of diamond file thus making a smaller file to act as an
instrument to prevent preparation errors such intermediate sized file as demonstrated in Figure
as apical transportation. This is demonstrated 14.27.
in Figure 14.26. – Narrow canals should be enlarged to atleast size #25
• Modifications for narrow root canals: or #30 K-files.
– Since even the smaller files tend to bind in narrow • Modifications for double-curved or s-shaped canals:
canals, they should not be forced in the canal. – After cleaning the apical foramen area, the curvature
– Smaller file is used till whatever length it penetrates in the middle third of the root canal is carefully
without forcing and then the canal is irrigated with eliminated by filing with Hedstrom file to straighten
sodium hypochlorite. the inner portion of the curve.
248 Short Textbook of Endodontics
Fig. 14.26 Schematic representation of modification of flutes Fig. 14.27 Modification of instrument to clean
of K-file. The outer portion of curve dulled with diamond file to and shape narrow root canals
prevent transportation of foramen in curved root canals (Courtesy of
Dr Vishal Rathod)
– After eliminating the middle third curve, only the thus preventing proper instrumentation of the apical
apical curve is left to be instrumented. portion of canal.
A mind-map to remember all points of step-back
Advantages of Step-back Technique technique is given in Figure 14.28.
– Preparation of apical third of the root canal till the The current trend is to use a crown-down approach for root
working length as shown in Figure 14.29D. canal preparation involving enlargement of coronal portions
– The final step in crown-down technique is the apical of canal followed by preparation of apical portions of canal.
finishing involving apical gauging and apical tuning. Thus, it involves dividing the radicular preparation into
• Advantages of crown-down technique: coronal, middle and apical one-third as shown in Figure
– It provides straighter, unimpeded access to the apical 14.30.
region of the canal by removing the coronal inter
ferences. Step 1: Pre-enlargement/Coronal 2/3rds Preparation
– It allows deeper penetration of irrigants.
– It removes bulk of pulpal tissue and microorganisms • Instruments used: Sequential use of Gates Glidden (GG)
and their products from the coronal portions of drills or various systems orifice shapers such as profile
the canal. As a result it minimizes or eliminates orifice shaper, etc. are used for coronal flaring. “Face off”
the extrusion of necrotic debris beyond the apical the orifices with an appropriate size of Gates Glidden
foramen. drill to create smooth glide path to facilitate placement
– It eliminates the constraint of the apical enlarging of subsequent instruments.
instruments. • Coronal scouting and shaping: Smaller K-files such as
– Flaring of the coronal 2/3rds of canal improves no.10 and then no. 15 are used for coronal scouting (i.e.
clinician’s tactile control of instrument preventing inserting the file to a predetermined length estimated
the preparation errors such as zipping. from a preoperative radiograph) to confirm the straight
• Disadvantages of crown-down technique: This technique line access and to establish a glide path.
is relatively free of disadvantages when carefully • Benefits:
performed to confine the instruments within the root – It allows for smooth, unobstructed path of the instru
canal space. ment into the canal.
Over-enthusiastic use of rotary files or GG drills should – Gives better tactile control while using small
be avoided as it can lead to preparation errors such as precurved negotiating files in the apical portions of
perforations or can weaken the root structure predisposing the canal.
it to fractures. – It provides access for large amount of irrigating
solution to reach the apical portion of canal and into
Step Down Technique of Root various irregularities of canal.
Canal Preparation (Goerig)
• Other names: Coronal two-thirds pre-enlargement
technique or reverse flaring technique.
• Technique:
i. After access Cavity preparation, hand instruments
such as K or H files are used in the root canal till the
length at which they bind in the canal.
ii. Use of GG drills to flare the coronal third of the root
canal.
iii. Determination of working length for the tooth and
creating an apical stop with no. 25 instrument.
iv. Remaining canal is shaped in step-down approach,
using a descending file sequence and progressing
about 1 mm per consecutive instrument apically.
v. Recapitulate with no. 25 instrument.
– It facilitates removal of accumulated dentinal mud. • Determining the working width, i.e. apical width to
– Since a bulk of pulp tissue and bacteria and which the canal can be enlarged.
their products have been removed by coronal • Shaping of the apical one-third of the canal (Apical
enlargement, there are less chances of inadvertently shaping).
inoculating them periapically.
– It helps in easier location of the apical foramen. Step 3: Apical Finishing—Apical Gauging and Tuning
After the coronal scouting, the coronal two-thirds of the
canal is shaped (Coronal Shaping). This is the final step that completes the root canal
preparation.
Step 2: Scout to Terminus and Apical 1/3rd Preparation It confirms whether uniform taper has been obtained
in the apical 1/3rd.
Apical scouting is the process of determining the anatomy It involves:
and cross-sectional diameter of apical 1/3rd of root canal. • Apical gauging: Process of determining the most apical
Fine instruments such as size #8, #10, #15 can be used for cross-sectional diameter of the canal where a hand or
apical scouting. rotary Endodontic instrument fits snugly at the terminus
It helps in determining the final size to which the and resists any further apical travel.
preparation should be enlarged and also helps determine This is done usually at the end of root canal
whether hand or rotary instruments should be used to finish preparation to determine the master apical file used
the apical one-third preparation. for final preparation of the canal based on which an
This step involves: appropriate corresponding master cone can be selected
• Negotiating the apical one-third of canal for obturation.
• Establishing patency • Apical tuning: Process of recapitulation by using a series
• Determining the exact working length of successively larger instruments in sequence until
• Establishing and confirming smooth glide path to the those instruments uniformly back out of the canal.
apical terminus. A mind-map to remember all points of crown-down
technique is given in Figure 14.31.
Step-back technique v/s Crown-down Technique - Third movement is to gently remove the
instrument from the canal in clockwise rotation
See Table 14.1. as shown in Figure 14.32C.
need to be strictly followed while working with – Then the middle 1/3rd of the canal is instrumented
instruments of different systems. – Finally, the MAR file has to be used again for
It is important to understand that no canal can be recapitulation to the working length.
completely prepared using rotary instrumentation
alone. Hand instrumentation generally is required prior, Group II: Instruments
during and sometimes after rotary instrumentation to
complete the preparation. Example is the Profile system.
Exploring the canal and achieving a glide path into
the canals is always done with smaller size K-files #6, #8, Profile System
#10, etc.
• Classification of Nickel-Titanium rotary instruments • About the instruments:
systems: Based on design, Cohen classified Nickel- – Profile instruments have greater taper as compared
Titanium rotary instruments as follows: to hand instruments
– Cross-section of profile Endodontic files shows
central parallel core with three equally shaped
U-shaped grooves along with radial lands as shown
in Figure 14.34.
– These instruments have negative rake angle which
makes them to cut dentin in planning motion
– Have tapers of 0.02, 0.04 and 0.06 (2%, 4%, 6%)
– Consists of series of 29 instruments with constant
proportion of increasing diameters (29%) which
were nonstandardized diameters. Later Profile series
was introduced with modified tips with standardized
diameters.
Figure 14.35 shows photograph of profiles for rotary
Group I: Light Speed Instruments System use.
• About the technique:
• About the instruments: Consists of set of 25 instruments – Coronal pre-enlargement
in sizes #20 to #100 including half sizes such as #22.5, – Estimation of tentative working length from pre-
#27.5. operative radiograph
These instruments are designed to have long, thin – Establish glide path with K-files up to size #15 or #20
noncutting shaft with 0.25–2 mm anterior cutting part. – Use profile orifice shapers in coronal portion of root
They are to be used at working speed of 1500–2000 canal in descending order, i.e. #4, #3, #2, #1
rpm with minimal torque. – Canal preparation with profile instruments of taper/
• About the technique: size: 0.06/30, 0.06/25, 0.04/30, 0.04/25 and so on
– Coronal pre-enlargement
– Using smaller stainless steel hand instruments such
as #8, #10, #15 K-files
– Determination of working length
– Apical gauging is done with light speed instruments
of increasing sizes until the instrument is found
to bind in canal just before reaching full working
length using a handpiece. This instrument is called
as FLSB (First Light Speed instrument to Bind before
reaching working length)
– Master Apical Rotary (MAR) size is the last instrument
used for apical preparation which may require 12 or
more pecking motions to advance from the point of
first binding to the working length Fig. 14.34 Cross-section of Profile Endodontic files
256 Short Textbook of Endodontics
– Initial glide path with #10, #15 K-files short of – Recommended speed for use: 300 rpm
approximate WL – Torque: 4–5.2 Ncm
– Gates Glidden drills may be used for enlargement of – Motion of use: Brushing motion away from external
orifices root concavities to facilitate file progression
– Establish a smooth glide path before protaper rotary – The Protaper Next sequence is the same always
instruments are inserted into the canal irrespective of length, diameter or curvature of root
– Use SX shaping file for enlargement of coronal third canal.
of canal, especially in shorter teeth Figure 14.39 shows photograph of the Pathfiles and Protaper
– Prepare the coronal third of the canal by inserting Next system rotary files namely X1, X2, X3, X4 and X5.
shaping file S1 passively in the canal, not more than • About the technique
two-thirds of estimated canal length – Pre-enlargement and straight line access to canals
– Irrigate with sodium hypochlorite and recapitulate – Establish glide path using small-sized hand files
– Use shaping file S2 to the estimated canal length determining the Working Length(WL)
– Irrigate and recapitulate – Path files can be used to establish a glide path
– Establish accurate working length using apex locator – Use X1 (17/04) file one or two times along glide path
and radiographs in presence of NaOCl until WL is reached
– Shape with S1 shaping file till working length – Irrigate, recapitulate and re-irrigate
– Shape with S2 shaping file till working length – Use X2 (25/06) similar way as X1, until WL is reached
– Then use finishing file F1 till working length – Irrigate, recapitulate and re-irrigate
– Carry out apical gauging with stainless steel K-files. – Apical gauging: Use #25 k-file. If it is snug at length,
Then finishing files F2 and F3 may be used if then that finishes the instrumentation
necessary as per the apical widening required. – If size #25 k-file is loose at length, then continue
shaping with X3 (30/07) and if necessary with
• Newer Nickel-Titanium rotary instruments systems: X4 (40/06), and X5 (50/06) gauging after each
Here few more Ni-Ti rotary instrument systems will be instrument with 30, 40 and 50 hand files respectively.
discussed which have been recently developed and are
being used by many clinicians. These include:
1. Protaper Next System
2. Revo S System
3. Wave One System
4. Reciproc Rotary File System
Both protaper universal and protaper next files have – Irrigate and recapitulate
variable taper unlike the constant-tapered ISO files. Both – Reshape whole length of canal in free progressive
share the same shaper file SX. The reduced tip and taper stroke without pressure using SU. Circumferential
of protaper next allows for a more conservative apical filing is recommended with SU.
preparation than that of protaper universal. Greater
efficiency is achieved with Protaper Next rotary files and 3. Wave One Single-file Reciprocating system
need to use fewer files than Protaper Universal system. • About the instruments
– It is a single-file system to shape the root canal
2. Revo S system completely from start to finish recommended for
• About the instruments: single-use
– The Revo S system consists of a set of three – Single file does the work that is traditionally
instruments namely: performed by three or more rotary Ni-Ti files
i. Shaper and Cleaner 1 (SC1) that has 6% taper – The Wave One Single-file reciprocating system
and has a black stopper and #25 diameter. consists of three files available in lengths of 21, 25
ii. Shaper and Cleaner 2 (SC2) that has 4% taper and 31 mm namely:
and has a gray stopper and #25 diameter. a. Wave One small file (yellow) used in fine canals
iii. Shaper Universal (SU) that has 6% taper and has with tip size of ISO 21 with continuous taper of
black stopper and #25 diameter. 6%
– These instruments have asymmetrical cross-section b. Wave One primary file (red) used in majority of
that provides more flexibility and less stress on the canals with tip size of ISO 25 with apical taper of
instrument. 8% which reduces towards the coronal end
– Speed required for Revo S rotary files is 250–400 rpm c. Wave One large file (black) used in large canals
– Torque needed: 0.8–1.2 Ncm. with tip size of ISO 40 with an apical taper of 8%
Figure 14.40 shows photograph of the Revo S rotary files. which reduces towards the coronal end.
• About the technique – Cross-section of Wave One files is convex triangular
– Coronal pre-enlargement using GG drills or orifice that improves the flexibility of the instrument
shaper such as Endoflare (Fig. 14.41) – Wave one rotary files can only be used with the Wave
– Establish glide path with #10 K-file or G files One Endodontic motor with its reverse reciprocating
– Use SC1 in free progressive movement without function
pressure. Only one stroke up to first resistance level. – Selection of single file is based on:
– Irrigate with NaOCl and recapitulate a. If 10 K-file resistant to movement, use Wave One
– Estimate the accurate working length small file
– Use SC 2 in three wave technique without pressure b. If 10 K-file moves to length easily, use Wave One
till the working length primary file
Fig. 14.40 Revo S rotary files (Courtesy of Micro Mega products) Fig. 14.41 Endoflare (Courtesy of Micro Mega products)
Cleaning and Shaping of the Root Canal System Including Working Length Determination 259
c. If 20 K-file or larger goes to length, use Wave One – Due to reciprocating movement:
large file. a. Stress on the instrument is relieved, which
Figure 14.42 shows the photograph of the Wave One small, reduces the risk of cyclic fatigue caused by
primary and large files. tension and compression
• About the technique b. Instrument remains centered in the canal
– Coronal pre-enlargement and straight-line access. c. It allows root canals to be prepared with one
Glide path can be established using the path files single instrument
– Use hand K-file into the canal in watch-winding – Usually there is no need to use hand files
motion to length or resistance – If the reciprocating instrument binds in the canal, it
– Use Wave One file approximately two-thirds of canal does not fracture because it will not rotate past the
length specific angle of fracture. As a result, creation of glide
– Irrigation with sodium hypochlorite and recapitu path to minimize instrument binding is not required
lation for the Reciproc instruments.
– Confirm the working length
– Use Wave One file to length. Recent system: Self-Adjusting File (SAF) system in which
cleaning, shaping, irrigation and agitation of the irrigant are
4. RECIPROC Rotary file system achieved simultaneously.
– It is also a single-file system to prepare the root canal • About the SAF instruments:
completely from start to finish recommended for – It is also a single file system
single-use – The Self-Adjusting File is a hollow, compressible
– It is made of M-wire Ni-Ti. So, it has higher flexibility Ni-Ti file which adapts itself to the root canal’s 3D
and greater resistance to cyclic fatigue anatomy
– Reciproc instrument alternates between clockwise – SAF is available in two diameters: 1.5 mm and
and counterclockwise rotation 2.0 mm
– Reciproc instruments are available as R25, R40 and – The SAF 1.5 mm is available in 3 standard lengths
R50 in 3 sizes 21 mm, 25 mm and 31 mm – 21 mm (active part: 16 mm), 25 mm (active part:
– Reciproc files are used with Reciproc motors, which 18 mm) and 31 mm (active part: 21 mm). The SAF
have precise angles of reciprocation. So, the risk of 2 mm is available in two lengths—21 mm and
instrument fracture is minimum 25 mm (Fig. 14.43B)
– Since the rotation in cutting direction is more than – The initial size of the SAF 1.5 mm is equal to ISO #150,
the reverse rotation, the instrument advances but its lattice-like structure can compress down to
towards the apex 0.2 mm when inserted into the canal, which is equal
to ISO #20. The compression is important to assure
that the SAF’s attempt to expand applies light lateral
pressure inside the root canal. The final apical size
follows the original root canal morphology and is
expected to be 2–3 ISO sizes larger than the initial
apical size
– The SAF 1.5 mm is compatible with canals with initial
apical size of ISO 20–30. SAF 2 mm for wider canals
with initial apical size of ISO 35–60 in maxillary
incisors and canines, in younger patients and in
cases of retreatment
– While removing dentin, SAF gradually expands to
enable the preparation of the root canal as achieved
by sequentially increasing the size of hand-operated
or motorized file
– The SAF is not a rotary instrument. Its main mode
of operation is vertical vibration at 5,000 rpm, at an
Fig. 14.42 Wave one: small (yellow), primary (red) and large amplitude of 0.4 mm, combined with a slow rotation
(black) files (Courtesy of Dentsply) (~80 rpm)
260 Short Textbook of Endodontics
– The SAFs abrasive surface, its compressibility and – SAF prevents canal transportation. File separation
adaptability, the application of light lateral pressure is prevented. Improved preservation of root canal
on the canal walls due to its compression—all walls
together circumferentially remove a thin layer of – Parts of SAF (Fig. 14.43A):
dentin in a “sandpaper effect” a. Compressible working end
– The continuous scrubbing motion of the SAF b. Shaft
is applied for 4 minutes, and combined with c. Rubber stopper
simultaneous irrigation, of sodium hypochlorite d. Irrigator barb-connects to a tube delivering
or any other irrigation fluid. The recommended irrigant. Made of medical grade polypropylene.
irrigation rate is 4 mL/min, and it is continuously e. Shank-Shank connects to the handpiece by
carried through the lumen of the SAF in a no- means of friction grip. Made of medical grade
pressure mode, suspending the created debris polypropylene.
and washing it away. The 5,000 vibrations per • About the technique with SAF:
minute help to continuously refresh the sodium i. Access cavity preparation done. Orifices are funneled.
hypochlorite, as well as create sonic agitation of the ii. Path is established up to no. 20 K-file
sodium hypochlorite irrigation, to achieve a high iii. Single instrument SAF used
level of disinfection iv. Simultaneous irrigating while working with SAF.
B
Figs 14.43A to B (A) Parts of SAF; (B) 1.5 mm and 2 mm SAF of different lengths (Courtesy of ReDentNOVA)
Cleaning and Shaping of the Root Canal System Including Working Length Determination 261
3. Root canal preparation using Ultrasonics and Sonics efficient form of vibration for preparation of root
Ultrasonic canal instrumentation canals.
– Ultrasonics in Endodontics use sound as an energy – Like the ultrasonic instrumentation, there is
source (at 20–25 kHz) and activates an Endodontic currently little support for the use of Sonic vibration
file. to prepare root canals, the only exception being the
– Mechanism: orthograde canal preparation during Endodontic
- Cavitation: The bubbles formed from action surgery.
of file become unstable, collapse and cause – Sonic and ultrasonic active irrigation: A stream
an implosion. During oscillation of file, the of solution is continuously delivered from the
continuous flow of irrigant solutions from the ultrasonic or sonic unit.
handpiece along the file causes cavitation or – Sonic and ultrasonic passive irrigation: Irrigant
implosion. deposited in the canal is activated. Passive irrigation
- Acoustic streaming: It is a process by which a after removing the smear layer, using #15 K-file in the
vibrating Endodontic file generates a stream of presence of 5.25% NaOCl, has been found to produce
liquid to produce eddies and flows of oscillation. cleaner canals as compared to hand instrumentation
It has been found to be useful in reducing the alone.
smear layer and loosening aggregates of bacteria, The use of sonics and ultrasonics for cleaning and
thus it is excellent for root canal cleaning. disinfection of the canal has been further explained
Earlier it was thought that mechanism is cavitation. in next chapter (Chapter 15: Disinfection of the Root
But now it has been found that Ultrasonics exerts its Canal System).
effects via acoustic streaming.
– Technique: The root canal is enlarged using hand 4. Laser-assisted root canal preparation technique
instruments to atleast size #20. Then the ultrasonic – Laser light travels straight. So, specific light-emitting
handpiece uses #15 K-file for canal shaping. The file probes have been developed in order to direct the
is activated for about one minute. laser energy into curved root canals.
The ultrasonic devices for Endodontic use – Er:YAG laser has been found to be effective and faster
(Endosonics) allow for delivery of irrigant such than step-back technique with K-files.
as NaOCl and the vibrating K-file causes canal – Erbium:YAG laser has been found to be effective in
preparation. debris removal.
– The ultrasonic vibration produces heat which warms – Er, Cr:YSGG (erbium, chromium: Yettruim scan
up the sodium hypochlorite irrigant, increasing the dium gallium garnet) is recently introduced
effectiveness of sodium hypochlorite. Thus, there is laser specifically for Endodontic therapy. The
synergistic relationship between the ultrasound and waterlase-hydrokinetic hard and soft tissue laser
sodium hypochlorite. device effectively cleans the root canal walls
– Ultrasonics produce cleaner canals but there is and prepares it for obturation. Water energizes
little support for use of ultrasonics in preparation the YSGG laser photons. So, no thermal side-
of root canals. So, now-a-days ultrasonically effects. Other advantages of this technique include
activated instruments are used for final root canal minimal patient discomfort and less postoperative
debridement rather than canal preparation. complications such as inflammation, swelling and
– The disadvantages include more chances of canal pain and also good antibacterial action.
transportation with the use of ultrasonics and the – Disadvantages of using Lasers:
ultrasonic insert may fracture in the canal causing - Access into severely curved roots not possible
iatrogenic problem. - High cost of equipment
- Operator and patient safety.
Sonic Canal instrumentation – Safety precautions while using lasers include: safety
– Sonic Endodontic handpiece attach to the regular glasses specific for each wavelength, warning signs
airline with an adjustable ring on the handpiece to and high-volume evacuation near the treated area.
adjust the air pressure to give an oscillatory range of
1.5–3 kHz 5. Noninstrumentation technique (NIT)
– The oscillatory motion of Sonic file in the canal is – NIT involves removing canal contents and accom-
a longitudinal motion, up and down, which is an plishing disinfection without the use of file.
262 Short Textbook of Endodontics
– This system consists of a pump, hose, a special valve • Instrumentation should always be done in a wet canal.
and a connector that is cemented into the access Use of irrigating solution such as sodium hypochlorite
cavity and cleaning action provided by oscillations is recommended in between instrument use.
of irrigation solution such as 1–3% NaOCl at reduced • Instrument stops should be positioned well while using
pressure. instruments to prevent their being forced through apical
– In this technique, the canal is not mechanically- foramen.
shaped or enlarged at all. • Establish glide path with K-files prior to rotary instru
– Mechanism: Cavitation loosens the debris and NaOCl mentation.
dissolves viable and necrotic tissue components • Instruments should be used in sequence of sizes and
which are then removed by suction. increase the file size only after current working file fits
– This technique is still under research and not loosely into the canal without binding.
commercially available. • Recapitulation should be done to loosen debris by
returning to working length with smaller files.
WHAT ARE THE PRECAUTIONS TO BE TAKEN • Precurve the files for instrumentation in curved canals.
• Instruments should be carefully used in apical third of
DURING INSTRUMENTATION?
canal to prevent trauma to the periapical tissues.
Precautions During Instrumentation • Smooth gentle reaming or rotary motion of Nickel-
Titanium instrument is recommended.
Do’s • Flutes of hand instruments should be cleaned of debris
to prevent canal blockage.
• Use only controlled finger pressure in manipulating an Figure 14.44 shows how the instrument blade is cleaned
instrument in the root canal. by holding between layers of gauze with some digital
• Instrument should be coaxed and not forced. pressure and is turned counterclockwise.
• The specific anatomy of each case should be carefully
reviewed prior to instrumentation. Dont’s
• Establish apical patency before starting biomechanical
preparation of root canal. • Do not force the instrument if it binds in the root canal.
• Keep all working instruments within the confines of root Force invites breakage.
canal to avoid procedural accidents. • Do not use instruments with deformed flutes. Discard
• Check the instruments to see whether flutes of blade are them.
uniformly spaced and are not deformed. This should be • Do not do instrumentation without lubrication.
done after each use. Instruments lubricated with EDTA should be used
• Accurate working length should be established and combined with copious irrigation with sodium
controlled throughout instrumentation. hypochlorite.
Fig. 14.44 Instrument blade is held between layers of gauze with Fig. 14.45 Taper lock of Nickel-Titanium rotary
some digital pressure and is turned counterclockwise (Courtesy of instrument in the root canal
Dr Vishal Rathod)
Cleaning and Shaping of the Root Canal System Including Working Length Determination 263
Disinfection of the
Root Canal System
This chapter describes the various methods for disinfection of the root canal system and discusses in
detail the various chemical agents used for root canal disinfection. It also explains about the smear
layer and its management in Endodontics.
You must know
• What is Disinfection of the Root Canal System?
• How to bring about Disinfection of the Root Canal System?
• Which are the Different Chemical Agents used for Disinfection of the Root Canal System?
• What is a Root Canal Disinfectant and What are its Requirements?
• What is Smear Layer and How is it Managed in Endodontics?
• What are Intracanal Medicaments?
• What are the Methods of Activation of Irrigating Solutions in the Root Canal System?
WHAT IS DISINFECTION OF THE Certain areas of canal walls, particularly in the apical
ROOT CANAL SYSTEM? third and in ribbon-shaped and oval canals, cannot be
cleaned mechanically, meaning that the residual bacteria
Different microbes such as bacteria, yeasts and possibly and other microbes exist in these untouched areas that
viruses, can infect the pulp. The microbial load is considered could survive.
minimal so long as the pulp is vital. But, with proceeding Since, the goal of Endodontic treatment is prevention
infection, pulp necrosis occurs and the entire root canal or treatment of apical periodontitis by elimination of
system becomes invaded by microorganisms leading to microorganisms from the root canal system, it can be said
apical periodontitis. that disinfection of root canal is an important cornerstone
The microorganisms present in the root canal can invade for successful Endodontic treatment because it reaches the
the periapical tissue, not only giving rise to pain but they microorganisms in dentinal tubules and in crevices, fins and
destroy the periodontium including bone. ramifications of the root canal system.
The microorganisms have to be eliminated from the root
HOW TO BRING ABOUT DISINFECTION
canal system to re-establish periradicular health.
OF THE ROOT CANAL SYSTEM?
“Disinfection is a process whereby microorganisms are
destroyed.” Disinfection of root canal system is brought about by
“Eradication of microorganisms from the root canal effective “Cleaning” and “Shaping” procedures.
system and neutralization of any antigens that may be Effective shaping: Mechanical instrumentation of the
left in the canal after destruction of microbes, is known as root canal with hand and rotary instruments to remove
disinfection of root canal”. vital and necrotic pulp tissue and eradicate microbes
Destroying 100% of the infective flora from the root canal from the accessible parts of root canal and shape the
system and the periradicular area is a challenge because of canals in such a way that directs and facilitates optimal
its anatomic complexity. irrigation, debridement and placement of local medicaments.
Disinfection of the Root Canal System 265
Effective cleaning: Use of chemicals to eradicate micro- WHAT IS A ROOT CANAL DISINFECTANT
organisms, dissolve necrotic tissue, remove necrotic AND WHAT ARE ITS REQUIREMENTS?
dentin and debris created from instrumentation by
means of antimicrobial irrigating solutions, detergents “A disinfectant is a chemical agent capable of destroying
and decalcifying materials and then placement of intra- pathogenic microorganisms”.
canal medicaments to render the root canal system free of “Root canal disinfectant is a chemical agent that brings
microbes. about eradication of microorganisms from the root canal
Without irrigation, mechanical instrumentation system”.
becomes ineffective rapidly due to accumulation of debris.
Without enlarging and shaping, the irrigating solutions Requirements of a Root Canal Disinfectant
cannot reach all parts of the root canal system.
Thus, shaping facilitates cleaning and cleaning facilitates A root canal disinfectant:
shaping. • Should: (a2s2)
“Cleaning” and “Shaping” are not two different steps – Have prolonged antimicrobial effect (bactericide,
of root canal procedure but are interdependent and are germicide, fungicide)
carried out together for complete disinfection of the root – Have low surface tension to produce good cleaning
canal system. effect
The various chemical agents used for effective cleaning – Be active in presence of blood, serum, etc.
will be discussed in this chapter. Various shaping procedures – Be stable in solution for prolonged duration
have been discussed in the previous chapter (Chapter • Should not: (I3s)
14). – Irritate the periapical tissues
– Interfere with healing and repair of periapical tissues
WHICH ARE THE DIFFERENT CHEMICAL – Induce cell-mediated immune response
– Not stain the tooth.
AGENTS USED FOR DISINFECTION OF
THE ROOT CANAL SYSTEM?
WHICH ARE THE DIFFERENT ROOT
CANAL IRRIGANTS?
Root canal irrigants are used for the purpose of:
• Removal of pulp tissue remnants
• Antimicrobial action
• Reducing friction during instrumentation, i.e. lubrication
• Debridement or lavage of debris from root canal
(Mnemonic tall).
canal. Files used in conjunction with the root canal irrigants B. Notched tip Monojet Endodontic needle (27 gauge)
carry the irrigants deeper in the canal by surface tension. (Fig. 15.1B)
On withdrawal of file, irrigant flows in the space occupied C. Bevelled needles (Fig. 15.1C)
by the file. D. Open ended blunt needles
Important factors to be considered for irrigation include: E. Maxi-Probe
Irritation potential of irrigants: Solutions that are toxic for F. Perforated needle- Example is Endovage (Goldman and
bacterial cells may be toxic for human cells also. So care others)
must be taken to avoid extrusion of irrigants into periapical A perforated irrigating needle delivers the irrigant 360
regions. degrees in the root canal. It is found that large volumes
of irrigant solution physically removes more material
Volume of irrigant: Volume of irrigant can affect cleanliness when delivered using perforated irrigation needle.
of root canal. It has been found that sodium hypochlorite Disadvantage of perforated needle is that it is delicate
and EDTA administered in larger volumes produced and may lose its shape when bent.
significantly cleaner root canal surfaces than smaller Figure 15.1 shows diagrammatic representation of
volumes. different types of irrigating needles.
Effective shaping: Root canals that have not been Stropko irrigator: It is a new device that can be used as an
instrumented are too narrow to be reached effectively by adjunct in few procedures of Endodontics.
disinfectants even when very fine irrigation needles are • It combines the delivery and recovery of irrigant in one
used. So, effective cleaning with optimum instrumentation probe as it consists of needle that delivers the solution
should be done. Also, intermittent agitation of canal with and an aspirator held in the same sheath that retrieves
a small instrument prevents accumulation of debris in the the delivered irrigant.
apical end of the root canal. • The Stropko irrigator places the perfect amount of air and
water pressure into the field. Its small, luer lock tips do
Choice of irrigating needle and manner of use: Larger gauge not impede visibility during irrigation or drying and are
needle (27–30) with wider diameter allow irrigant to be excellent for use under microscope. It fits most triplex
flushed and replenished more quickly, but may not allow air/water syringes (3-way syringe of dental chair).
cleaning of apical and narrower areas of root canal system. • It is a valuable tool to rinse and dry precisely for
Excess pressure or wedging of needles into root canals improved vision during every procedure. It can clean
during irrigation should be avoided to prevent extrusion and dry root-end preparations when performing micro-
of irrigant into periapical tissues. The needle is bent to an surgical procedures. Also, it can air-dry the canal system
obtuse angle closer to the hub of the syringe to allow for with a light touch of air prior to obturation for improved
easier access and entry into the root canal orifice. seal.
In modern systems, the irrigation solution is delivered Figures 15.2A and B shows the Stropko irrigatorirrigation
with a fine caliber needle passively in the canal, in large tips and adapter.
volume and debris is aspirated with a good suction device.
A B
Figs 15.2A and B (A) Blue irrigation tips; (B) Adapter of the Stropko irrigator
(Courtesy of Sybron Endo)
Advantages
• It has excellent antimicrobial properties
• It is a powerful solvent of necrotic pulp tissue and
organic debris
• It acts as a lubricant, antiseptic and bleach.
• It has strong proteolytic effect
• It is readily available, inexpensive
Disadvantages
• Cannot remove smear layer.
• It does not have effect on inorganic material
• Unpleasant taste
• Due to its inability to remove dentin and smear layer, its
use has to be combined with demineralizing agents for
effective cleaning of inaccessible areas such as lateral Fig. 15.4 Factors affecting the efficacy of NaOCl
canals.
• Can have chemical interactions with other irrigants
used. It has been found that sodium hypochlorite can
become ineffective if it comes in contact with EDTA or effects of toxicity such as excruciating pain, bleeding
chlorhexidine gluconate 2%). from periapical tissue, swelling, abscess, osteonecrosis,
• Toxicity: Extrusion of high concentration of sodium paresthesia, etc. Pain may subside within 2–3 days.
hypochlorite can cause serious damage to periapical Swelling may increase for first day and then gradually
tissues. decrease.
• Solution has to be replenished frequently due to free
chlorine, to constantly renew fluid in root canal during Precautions to be Taken for Safe Irrigation
instrumentation.
with Sodium Hypochlorite
How to Increase Efficacy of Sodium Hypochlorite? • Bend the irrigating needle so that it can easily penetrate
deeper portions of canal without binding and mark the
1. NaOCl solutions can be heated to temperatures ranging working length on needle with this bend or a rubber
from 45oC to 60oC using syringe warmer or ultrasonic stop to prevent extrusion of sodium hypochlorite into
devices. Using heated sodium hypochlorite potentiates periapical area.
the antimicrobial and tissue dissolving effects of NaOCl. • Irrigating needle should remain loose in the canal to
2. Use NaOCl along with ultrasonic energy (Agitation) allow back flow of fluid and should not bind.
3. Contact time: Antimicrobial efficacy of NaOCl is directly • Continuously move the irrigating needle up and down.
related to its contact time in the canal. • Careful use of patency files that should not extend farther
4. Volume of irrigant: NaOCl administered in large volumes than the periodontal ligament.
produces significantly cleaner root canal surfaces than • Deliver irrigating solution passively without exerting
the smaller volume. pressure while injecting.
5. Concentration of NaOCl: Higher concentrations of • Administer irrigant dropwise slowly and gently and not
NaOCl (5.25%) has more antimicrobial efficacy than in a rapid projectile motion.
lesser concentrations (2.5% and 0.5%) • Always hold a sterile gauze sponge around the tooth
Figure 15.4 summarizes the factors affecting the efficacy to be irrigated to prevent spilling of excess solution in
of NaOCl. mouth and it also helps monitor the debris removal from
root canal. It has been demonstrated in Figure 20.20 in
Sodium Hypochlorite Accidents Chapter 20: Endodontic Mishaps: Management and
Prevention.
Accidental injection or extrusion of sodium hypochlorite A mind-map to remember all points of sodium
during irrigation into periradicular tissues can cause hypochlorite is given in Figure 15.5.
Disinfection of the Root Canal System 269
H2O2 can be used for cleaning the pulp chamber from blood
and pulp tissue remnants. H2O2 has antimicrobial activity
against bacteria, viruses, yeasts and bacterial spores.
Figure 15.6 shows photograph of commercially available
hydrogen peroxide.
In the past, hydrogen peroxide was used as an irrigant
in conjunction with sodium hypochlorite.
It was thought that if alternate irrigation is done with 3%
hydrogen peroxide and 5.2% sodium hypochlorite, it can
cause following beneficial action:
• Effervescent action of hydrogen peroxide that can push
the debris out of the root canal through the least resistant Fig. 15.6 Commercially available hydrogen peroxide for irrigation
orifice into the pulp chamber. (Courtesy of Mr Amar, Dr Dabholkar’s clinic)
270 Short Textbook of Endodontics
• The solvent action of sodium hypochlorite for dissolution even after the completion of treatment. This property is
of organic debris. called substantivity meaning long-term continued effect
• The disinfecting and bleaching action of both solutions. that may reduce the effect of postoperative coronal leakage.
Alternate irrigation with hydrogen peroxide and sodium
hypochlorite was done in the past. Antimicrobial Action
But, now, this combination is no longer used due to the
following reasons: The CHX has an excellent antimicrobial activity.
i. It has been found that combination of hydrogen peroxide • It is effective against gram-positive and gram-negative
with sodium hypochlorite, tends to reduce the tissue bacteria and yeasts.
solvent property of sodium hypochlorite. • But ineffective against mycobacteria and bacteria spores.
ii. No additional cleaning effect was found with this • Two percent solution of CHX is highly effective against
combination. Enterococcus faecalis.
iii. The oxygen-free radicals that are released have the It has been found that higher concentrations of NaOCl
potential to reduce the bonding of resin to dentin. such 5.25% can kill E. faecalis in 30 seconds but lower
concentrations of NaOCl may take longer, i.e. about 5–30
Chlorhexidine Digluconate (2%) minutes for killing E. faecalis whereas 2% CHX can kill
E. faecalis in 30 seconds or even less.
Chlorhexidine digluconate can be used in Endodontics as
an irrigating solution and as an intracanal medicament. Advantages
Figure 15.7 shows the photograph of commercially
available chlorhexidine digluconate. • Excellent antimicrobial activity
• Relatively nontoxic
Mechanism of Action • Substantivity property
• Does not have bad odor.
Chlorhexidine Digluconate (CHX) has a cationic molecular
component which attaches to negatively charged cell Disadvantages
membrane areas resulting in cell lysis.
The CHX penetrates the cell wall and attacks the bacterial • Does not have tissue dissolving property
cytoplasmic membrane or the yeast inner membrane. CHX • Its activity is dependent on the pH and its effectiveness
can cause coagulation of intracellular components in high reduces in presence of organic matter
concentrations. • Ineffective against mycobacteria and bacterial spores.
When CHX is applied to dentin, it binds to hydroxyapatite, So, it cannot be used for disinfection of gutta-percha
producing a lasting reservoir of chlorhexidine, that remains cones.
• The CHX cannot remove the biofilm, that may remain
within the canal and continue to express its antigenic
potential thus affecting the seal of root canal filling.
• The CHX has cytotoxic effect when it comes in direct
contact with human cells.
root canal walls. So, saline wash should be used in between WHAT IS SMEAR LAYER AND HOW IS IT
both of them. The brownish-orange color may be due to iron MANAGED IN ENDODONTICS?
impurities in hypochlorite. This mixture should not be used
for irrigation of root canal system. Whenever the wall of a root canal is instrumented, whether
by hand or rotating instruments, the parts of dentinal wall
Quaternary Ammonium Compounds touched by an instrument, gets covered by a surface layer
called smear layer.
These are detergents that were used for irrigation in the past. Smear layer consists of dentin shavings, cell debris
They have low surface tension and can remove lipid pulp and pulp remnants. Thus it consists of both organic and
breakdown products thus aiding in pulp space cleaning. inorganic components and can have thickness of 1–5 µm.
Quarternary ammonium compound such as Cetrimide It has two separate layers:
may be added to EDTA in EDTAC to provide some 1. Loose superficial deposit
antimicrobial effect. 2. An attached stratum that extend into the dentinal
Quarternary ammonium compounds are no longer used tubules forming occluding plugs.
as irrigants due to their toxicity.
Removal of Smear Layer: A Controversial Issue
Antibiotic Containing Irrigating
Studies have been carried out and different clinicians have
Solutions such as MTAD
given their opinion regarding whether the smear layer
MTAD is a recently introduced root canal irrigant which is should be removed or left behind.
a Mixture of a Tetracycline isomer, citric Acid and a surface Recent evidence indicates that it is beneficial to remove
active Detergent. the smear layer before obturation.
– Mechanism of action: EDTA forms a calcium chelate for finishing the preparation as it removes the smear
with calcium ion of dentin. The dentin becomes layer and provides a cleaner surface against which
friable and easier to instrument. obturation materials are adapted.
By removing the dentinal debris from root canal walls – Decalcifying process of 17% EDTA is self-limiting
that are produced during preparation. since the chelator gets used up. So, EDTA needs to
↓ be replaced through frequent irrigation to have a
EDTA opens dentinal tubules continuous effect.
↓ – Some form of EDTA used during cleaning and
Allows better penetration of disinfectants shaping of root canals can help achieve canal
Thus EDTA indirectly exerts an antimicrobial effect by patency, enlargement, floatation of dentinal debris
facilitating cleaning and removal of infected tissue and by and pulp remnants and with additives, debridement
enhancing antimicrobial effect of locally used disinfecting and disinfection. Thus it prevents the canal from
agents in deeper layers of dentin. getting blocked.
A chelating agent holds the debris in suspension and A mind-map to remember all poins of EDTA is
causes lubrication and emulsification. given in Figure 15.10.
• Available as: 2. Citric acid: Can be used for irrigation of root canal and
– Liquid of concentration 15–17%: This is called as for removal of smear layer.
aqueous chelator. 17% liquid buffered solution is Fifty percent concentration of citric acid is effective.
commonly used. Its photograph shown in Figure Citric acid can remove only the inorganic portion of
15.9. smear layer, so complete removal of smear layer requires
– Gel: This is called as viscous chelator. Discussed in irrigation with 5.25% NaOCl before or after citric acid
Chapter 13 “Endodontic Access Cavity Preparation”. irrigation.
• Actions: Citric acid demineralizes intertubular dentin making the
– EDTA can help to open very narrow (hair-fine) root tubular openings larger than that caused by use of EDTA.
canals. Citric acid has weak antimicrobial activity.
– EDTA can decalcify to a depth of approximately 3. MTAD: Explained already.
50 µm if used liberally. 4. Carbamide peroxide and salvizol were tried but not
– EDTA opens dentinal tubules. found reliable in removing smear layer.
– Seventeen percent EDTA combined with 5.25%
NaOCl used alternately can effectively remove the WHAT ARE INTRACANAL MEDICAMENTS?
smear layer. One minute rinse of 17% EDTA is used
“Antimicrobial medicaments that are placed in the root
canal, in case of multiappointment Endodontic treatment
of a tooth, especially the one with the necrotic pulp, in
which the biomechanic instrumentation and irrigation with
antimicrobial solution may not completely eradicate micro-
organisms and further disinfection may be necessary, are
called intracanal disinfectants or intracanal medicaments
used as intracanal dressing”. They are also referred to as
Inter-appointment Medicaments.
Calcium Hydroxide
• Calcium hydroxide was introduced in dentistry by
Fig. 15.9 Commercially available 17% liquid EDTA for removal of Hermann in 1920.
smear layer (Courtesy of Mr Amar, Dr Dabholkar’s clinic) • Most widely used intracanal medicament.
274 Short Textbook of Endodontics
Calcium hydroxide neutralizes the biologic activity of with a lentulospiral homogeneously upto the working
bacterial lipopolysaccharide, thus reducing its effect. length.
As a result: • Calcium hydroxide combined with 0.12% chlorhexidine
– The necrotic tissue becomes more susceptible to the solution may be applied as an intracanal medicament
solubilizing action of sodium hypochlorite in the [Ca(OH)2 – CHX 0.12% mixture].
next appointment. • Advantages of calcium hydroxide:
– Continued stimulation of inflammatory response – It stimulates periapical healing.
caused by dead cell wall material, remaining even – It inhibits root resorption.
after the bacteria are killed, is prevented. Thus it acts • Disadvantages of calcium hydroxide:
as a physical barrier for the ingress of bacteria. – It is found to be ineffective against E. faecalis, that
• Indications of calcium hydroxide as an intracanal is often associated with persistent Endodontic
medicament: infections
i. Calcium hydroxide is quite effective in case of – It may be sometimes difficult to remove from the
weeping canals. In case of a tooth with large root canal walls
periapical lesion undergoing Endodontic treatment, – It decreases the setting time of zinc oxide eugenol
a constant clear or reddish exudation occurs. cements
Root canals in which such exudates are found are – Its action as an antiseptic is slow and short-lasting.
called weeping canals. Tooth often is asymptomatic Figures 15.11 and 15.12 shows photograph of
and bacterial culture report is negative. Antibiotics commercially available calcium hydroxide.
are not useful in such cases. Calcium hydroxide plays
an excellent role in such cases. Chlorhexidine Digluconate (CHX)
ii. Calcium hydroxide is found to be an effective
intracanal medicament in cases of pulp necrosis and • The CHX in a gel form or as a mixture with calcium
apical periodontitis. hydroxide can be used as an intracanal medicament in
iii. It is used in pulp therapies: indirect and direct pulp between appointments.
capping and pulpotomy cases. • Studies have shown that Ca(OH)2 – CHX mixture is more
iv. Apexification effective against E. faecalis than pure Ca(OH)2.
v. Resorption cases • While some studies have shown that pure Ca(OH)2, or
vi. In root canal sealers. 2% CHX gel and combination of both, can give equally
• Application of calcium hydroxide in the canal: Calcium good results.
hydroxide mixed with sterile water or saline making a • The CHX can be an effective intracanal medicament
mixture that is thick enough to carry as many calcium due to its substantivity property and long-lasting
hydroxide particles as possible, is placed in the canal antimicrobial effect.
Fig. 15.11 Commercially available calcium hydroxide Fig. 15.12 Commercially available calcium hydroxide
(Courtesy of Mr Amar, Dr Dabholkar’s clinic) with iodoform (Courtesy of Ammdent)
276 Short Textbook of Endodontics
Generally, locally used antibiotics have bacteriostatic Disinfectant action of halogens has been found to be
action, which may not be effective in necrotic teeth. inversely proportional to their atomic weight.
Such medicaments have been thought of, for infection • Chlorine:
control in Endodontics, but not found to be effective. – Chlorine has lowest atomic weight and greatest
disinfectant action
Phenol and Phenol Derivatives – Chlorine may be used as an intracanal dressing in
the form of Chloramine T.
• Mechanism of action: Phenol is a protoplasm poison that • Iodine:
causes necrosis of soft tissue. – Iodine potassium iodide (IKI) is effective against
Paramonochlorophenol a wide spectrum of microorganisms found in root
• Derivatives of phenol Thymol canals including resistant microorganisms like
Cresol E. faecalis.
phenol derivatives are stronger antiseptics and toxins – Mechanism of action: Iodine acts as oxidizing agent
than phenol. by reacting with free sulfhydryl groups of bacterial
• Concentration: Optimal antibacterial effect is found to enzymes.
be at 1–2%. – The IKI is an effective disinfectant against infected
For dental use, concentration of 30% that has been used dentin but iodine may have possible allergic
was found to have quite low antimicrobial effect and is reactions in some patients, that limits its use.
of short duration.
Phenol and phenol derivatives are highly toxic to Bioactive Glass
mammalian cells and their antimicrobial effectiveness
does not balance their potential toxicity. Use of bioactive glass as an intracanal medicament is under
Phenol and phenol derivatives are no longer used as research.
intracanal medicaments. Resilon, a new root canal filling material contains
• Camphorated parachlorophenol (CMCP): Camphoration bioactive glass.
results in less toxic phenolic compound. This is due to
slow release of toxins to the surrounding tissues. Superoxidized Water
Camphor serves as vehicle and a diluent, thus reducing
the irritating effect of pure parachlorophenol. • Saline is electrolyzed to form superoxide water.
CMCP was widely used in the past. It used to be applied • This solution has an antibacterial effect.
into the pulp chamber to act as devitalizing agent soaked • But its effectiveness reduces by contact with albumin.
with a moist cotton pellet covered with temporary • It is nontoxic to tissues.
cement such as zinc oxide eugenol. Its use as an intracanal medicament is still under
But now CMCP is no longer used. research.
length and are available in three sizes: small – Lasers such as Er: YAG and Er.Cr.:YSGG have been
(yellow 15/02), medium (red 25/04), and large found to facilitate removal of smear layer.
(blue 35/04). – It has been found that the antibacterial effect
– The EndoActivator® System brings about the of lasers in root canal was inferior to NaOCl
debridement and disruption of the smear layer irrigation.
and biofilm. – Effect of laser is dependent on the applied output
Figure 15.15 shows the photograph of the power and is specific for different bacteria.
Endoactivator system. – Gutknecht et al reported excellent antibacterial
iii. Ultrasonics efficiency against E. faecalis using holmium:yttrium-
– Ultrasonic energy (30–40 KHz) can be combined with aluminium-garnet (Ho:YAG) laser.
irrigant for disinfection. v. Ozonated water irrigation
– Ultrasonic energy is found to be more effective in – This has been tried as an irrigant and few studies
removing artificially created debris. show that it is effective antimicrobial agent against
– Many studies have shown that ultrasonics, together bacteria, fungi, protozoa and viruses.
with an irrigant, contributed to better cleaning Ozone in aqueous or gaseous phases has a strong
of the root canal system than irrigation and hand oxidizing power and it shows rapid antimicrobial
instrumentation alone. Physical mechanisms effects.
of cavitation and acoustic streaming of irrigant – It is relatively safe and nonmutagenic.
contribute to the biological chemical activity for – Mechanism:
maximum effectiveness. a. Ozone destroys cell walls and cytoplasmic
– Ultrasonics help irrigants penetrate into the complex membranes of bacteria and fungi
canal systems, which are not easily reached by b. Permeability increases which leads to ingress of
normal irrigation. ozone causing microbial death.
– Many commercially available specialized ultrasonic Figure 15.16 shows commercially available ozone device
tips for Endodontic use are available. For example, for Endodontics.
Irrisafe tips (Satellac).
iv. Lasers Negative Pressure Irrigation,
– Role of lasers in eradicating the root canal microbes
e.g. EndoVac Irrigation System
has been studied.
– Nd:YAG and Diode lasers have been used for EndoVac irrigation system is a true apical negative pressure
disinfection of the root canal system. system that draws fluid apically by way of evacuation.
– CO2 laser microprobe attached to special handpiece Irrigation solutions are sucked away from the apical
can also be used for disinfection of root canal. foramen, virtually eliminating the risk of irrigation.
Disinfection of the Root Canal System 279
Fig. 15.16 Commercially available ozone machine Fig. 15.17 EndoVac irrigation system
(Courtesy of Mr JP Mishra, Sanjeevani ozone products) (Courtesy of Sybron Endo)
Figure 15.17 shows photograph of the EndoVac irrigation 3. Hegde MN. Textbook of Endodontics (1st edn.), Emmess Medical
system. Publishers; 2009.pp.227-47.
4. http://www.endoruddle.com/inventions.html.
5. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics 6 (6th edn.)
BIBLIOGRAPHY BC Decker Inc, Hamilton; 2008.pp.992-1011.
1. Cohen S, Hargreaves KM. Pathways of Pulp (9th edn.), St. Louis: 6. Mohammadi Z, Dummer PMH. Review-‘Properties and
Mosby; 2006.pp.258-62 and pp.339-48. applications of calcium hydroxide in Endodontics and dental
2. Grossman L, Oliet S, Del Rio C. Endodontic Practice (11th edn.). traumatology,’ International Endodontic Journal; 2011.pp.697-
Varghese publication; 1991.pp.228-33. 730.
16
CHAPTER
Obturation of
Root Canal System
This chapter discusses in detail the various aspects of obturation including the different materials
and techniques used for obturation of the root canals.
You must know
• What is Obturation of Root Canal?
• What are the Objectives of Obturation?
• When to do Obturation of the Root Canal?
• What should be the Apical Extent of Obturation?
• With what should we do Obturation?
• What are the Requirements for an Ideal Root Canal Filling Material?
• Which are the different Core Materials that can be used for Obturation?
• What are Root Canal Sealers and what are the Requirements of an Ideal Root Canal Sealer?
• What is the Purpose of using a Root Canal Sealer?
• How is the Sealer Placed in the Root Canal?
• Which are the different Root Canal Sealers used in Obturation?
• Root Canal Sealer in detail
• What is the Preparation for Obturation?
• How to do Obturation? Which are the different Obturation Techniques?
• How should an Ideal Obturation be?
• What can go Wrong in Obturation?
• What is the Importance of Coronal Seal and how can we Enhance it?
Related to Procedure
Fig. 16.1 Mind-map of objectives of obturation • When the root canals have been optimally enlarged and
thoroughly cleaned and shaped to the appropriate size
between the root canal system and the periodontium as and to the correct working length, the canals can be
well as the oral cavity. considered ready for obturation.
• In case of asymptomatic teeth with vital pulp and
Current Concepts Related to not much of procedural difficulty, obturation can be
completed in the same visit of access opening and
Obturation of Root Canal
preparation of canals [(Single Visit Endodontics (SVEs)].
• “Hermetic seal”: The term ‘hermetic’ seal of root canal
described by Grossman is considered inaccurate now. Related to Patient
The dictionary meaning of this term:
‘hermetic’ = sealed against escape or entry of ‘air’ or • The tooth should be asymptomatic, i.e. no pain, no
made airtight by fusion or sealing. swelling or signs/symptoms of infection in relation to
But in the obturation of root canals, the main concern the involved tooth.
is not related to ‘air’, the concern is about ‘fluid’ leakage • Patient’s general health condition should be considered.
and bacterial leakage either apically or coronally. Few medical conditions may require multiple short
So, the accurate term to use would be ‘impermeable’ appointments for completion of treatment whereas
seal, ‘fluid-tight’ seal or ‘fluid impervious’ seal and not some physically compromised or aged patients may not
‘hermetic’ seal. be able to come on multiple visits.
• Coronal seal: Establishing and maintaining “coronal
seal” is essential for the success of root canal treatment Related to Tooth
and for the long-term prognosis of an Endodontically
treated tooth. When the root canals have been optimally cleaned and
A good post-Endodontic restoration with a shaped.
permanent restorative material (definitive restoration) • The prepared canal should be ‘dry’, with no exudation
must be placed as soon as possible after obturation to or weeping of fluids into the radicular space
reduce the chances of coronal microleakage. • There should be no foul odor from the canal
Studies have shown that coronal seal can be
enhanced by sealing the orifices with special adhesives
and bonded restorations (Intraorifice barriers). The
floor of the pulp chamber can be covered with a lining
of bonded material or dual cure resin-modified glass
ionomer cement.
Such a coronal-radicular restoration and other
considerations and methods for the restoration of an
Endodontically treated teeth are described in detail
in Chapter 21 (Restoration of Endodontically Treated
Teeth).
Classification of Root Canal Filling Materials • You will first sterilize gutta-percha cone using sodium
hypochlorite {point (1)}
• Then you will introduce it in the canal {point (2)}
• When GP is inserted, you expect, it should {points
(3),(4)(5)} and it should not {points (6),(7),(8)}
• Then, you would like to check if the root canal (RC)
filling was done properly, so you will take a radiograph
to confirm {point (9)}
• In case of error, you would like to remove it {point (10)}
and re-do it).
– It has the property of plasticity or flow when heated • When heated, the material changes to α-phase and
or exposed to solvents, which is made use of for becomes tacky and pliable. It can be made to flow under
obturation. pressure.
– Heated thermal conductivity through gutta- • The unheated phase is the β-phase when the material is
percha occurs over the length of 4–5 mm. Vertical a solid mass and compactable. It is purified, commercial
compaction and adaptation of thermosoftened form which is used to manufacture Endodontic GP
gutta-percha are also effective over the range of 4–5 points.
mm. • Temperatures for phase transitions of gutta-percha:
Although gutta-percha has good biocompatibility, – Transition from β-phase to α-phase occurs at 115oF
studies have been done to evaluate the tissue toxicity exerted (46oC), i.e. about 3–8oC above the body temperature
by gutta-percha in case of an overfill or overextension of is sufficient to mold gutta-percha.
gutta-percha into the periapical area. It was found that the – An amorphous phase develops at 130 o –140 o F
intensity of inflammatory response was determined by the (54o–60oC)
size of gutta-percha particles. – Gutta-percha crystallizes to α-phase when cooled
Larger gutta-percha particles caused Less inflammation very slowly
around them and appeared well encapsulated, whereas – Gutta-percha returns to β-phase with normal
with smaller gutta-percha particles a more intense localized cooling.
response was seen. Mechanical properties of both α- and β-phase are
It was also found that sealer was the most toxic portion same, but when α-phase gutta-percha is heated
of the sealer-gutta-percha obturation. and cooled, there is less shrinkage. α-phase is
• Limitations: more dimensionally stable for thermoplasticized
– Gutta-percha lacks rigidity. Smaller size gutta-percha techniques.
bends easily under lateral pressure. • Commercially available gutta-percha cones:
– Gutta-percha is difficult to introduce into a narrow – Gutta-percha cones are available as:
canal.
– Gutta-percha lacks adherent properties. So, it cannot
be used as the sole filling material to seal the root
canal space.
– Gutta-percha cannot seal the canal apically or
laterally unless combined with a sealer.
– Gutta-percha has limited shelf life. It becomes brittle
with age, probably through oxidation.
– Warmed Gutta-percha shrinks as it returns to body
temperature. So, it was recommended by Schilder
that vertical pressure should be applied in case of
warm gutta-percha techniques to compensate for
volume changes that occur as cooling takes place.
• Forms of gutta-percha:
Sorin and Oliet described the aging process of gutta-percha. Gutta-percha for Newer Obturation Systems
They introduced a technique to rejuvenate the aged brittle
gutta-percha cones by momentary immersing it in hot tap • T h e r m o pl a st i c i z e d gu tt a -p e rc h a : The new er
water (above 55oC) until the grasping forceps indents the thermoplasticized obturation systems use gutta-
softened gutta-percha followed by immediate quenching percha pellets that are inserted into a delivery system
in cold tap water (less than 20oC) for several seconds. gun and heated to 150o–200oC prior to delivery into
the canal system. 20, 23 or 25 gauge needles can then
Gutta-percha Sticks be used to deliver the warmed and softened gutta-
percha. Intermittent vertical compaction of injected
These are different from gutta-percha points. They are not thermosoftened gutta-percha is carried out every
used for obturation. 3–5 mm so as to prevent shrinkage and loss of volume.
Their applications include: • Carrier-based gutta-percha: Obturators such as thermafil
• To check vitality of tooth by heat test obturators, GT obturator, simplifil, successfil make use
• As temporary restoration of metal or plastic carriers which are coated with alpha-
• Can be used as slow separators. phase gutta-percha.
B
A
B C
Figs 16.4A and B Conventional standardized color-coded gutta- Figs 16.5A to C Standardized Protaper gutta-percha points-F1, F2
percha points: (A) Gutta-percha points no. 15–40; (B) Gutta-percha and F3 for obturation: (A) F1 gutta-percha point; (B) F2 gutta-percha
points no. 45–80 (Courtesy of Dentsply) point; (C) F3 gutta-percha point (Courtesy of Dentsply)
286 Short Textbook of Endodontics
Sealer penetration into the dentinal tubules is enhanced point of collision, the cement flow is forced to travel
by removal of smear layer. laterally. This creates forces to fill the lateral canals
Sealer penetration of dentinal tubules is affected by the and any other invaginations that may exist.
method of obturation. Thermoplastic techniques produce • Ultrasonics: Ultrasonics can be used to place the sealer
deeper sealer penetration. in the root canal. It has been found that ultrasonic
The root canal walls can be coated with the sealer using: placement of sealer is superior to manual techniques.
• Master cone: The core material which is going to serve
as master cone can be used to coat the canal walls with WHICH ARE THE DIFFERENT ROOT CANAL
the sealer cement.
SEALERS USED IN OBTURATION?
• Paper points: Appropriate size paper point can be used
to coat the canal walls with sealer cement. • Different root canal sealers include:
• Files or reamers: Appropriate size file or reamer can be – Zinc oxide containing sealers
used to coat the canal walls with sealer cement. – Calcium hydroxide containing sealers
• Lentulospiral: Lentulospiral is used with a slow-speed – Resin sealers
contra-angle handpiece in anticlockwise direction – Glass ionomer-based sealers
to deliver the sealer into the canal. While using – Medicated sealers
lentulospiral, it is important that it is started or stopped – Silicone-based sealers
outside the root canal otherwise it may cut into the canal – Solvent-based sealers
wall and might break. Figure 16.10 shows photograph of – Urethane methacrylate sealers
a Lentulospiral. • Sealers can be classified as (as per ANSI standard no.
• Bidirectional spiral: Bidirectional spiral cement carrier 57):
coats the canal walls and prevents excess cement from
exiting apically.
– Mechanism: Its coronal grooved spirals travel in
an apical direction and carry the sealer cement
apically. Its apical reverse spirals flow the cement in
a coronal direction simultaneously, thus preventing
the periapical extrusion of the sealer. Also, the two
independent flows of cement collide in the area
where the grooved spirals change direction. At this
There are different formulations of this sealer, which Pulp Canal Sealer (Kerr)
have zinc oxide as the primary component such as:
It is also a Zinc oxide and eugenol based sealer. It has been
Grossman’s Sealer used widely as a sealer for the warm gutta-percha, vertical
condensation method.
Grossman developed the original formula of Zinc Oxide • Setting time: 1–2 hours
containing sealer, which satisfied most of the ideal • Advantages:
requirements of an ideal root canal sealer. It is available as – Good flow and variable viscosity
Roth’s sealer. – Fast setting as compared to other sealers
• Composition: – Nonresorbable
Powder Liquid – Extended working time
(ZB2S2) – Eugenol – Blocks pain due to zinc eugenate
– Zinc oxide 42 parts • Disadvantages: Not compatible with resin containing
– Staybelite resin 27 parts core materials or resin containing luting cements for
– Bismuth subcarbonate 15 parts posts.
– Barium sulfate 15 parts
– Sodium borate, anhydrous 1 part Rickert’s Sealer
• Setting time: Hardens in 2 hours at 37oC and 100% • Composition:
relative humidity. It sets in root canal within 10–30 Powder Liquid
minutes. Zinc oxide Oil of clove,
• Manipulation: ZOE sealer powder and liquid are slowly Precipitated silver Canada balsam
mixed on a sterile glass slab with a sterile spatula to a White resin
proper consistency of a smooth, creamy mix. When the Thymol iodide
flat blade of the spatula is lifted up, the cement should • Advantages:
“string out” for about an inch before breaking or the – Germicidal
cement should cling to the inverted spatula blade for – Excellent lubricating and adhesive qualities.
10–15 seconds before dropping from spatula. This is • Disadvantages: Staining of tooth structure from the silver
the test given by Grossman to check for the proper if it is not completely removed from the coronal tooth
consistency of the sealer cement. structure.
• Insertion: After drying the root canals, a smooth broach,
reamer or file or Lentulospiral is used to carry small Tubli-seal
amounts of cement into the canal and the canal is coated
in lateral or rotary motion gently without forcing any Tubli-SealTM is a Zinc oxide eugenol root canal sealer. Figure
sealer into periapical tissues. 16.11 shows the photograph of the same.
• Advantages: Available as 2 paste system developed as an alternative
– Antibacterial to silver containing Rickert’s sealer.
– Resorbs if extruded into periapical tissues It is light in color, nondarkening and radiopaque.
– Plasticity • Composition:
– Good sealing potential Base paste Catalyst paste
– Slow setting Zinc oxide Eugenol
– Nonstaining Barium sulfate Thymol iodide
• Disadvantages: Not compatible with resin containing Mineral oil Resin
core materials or resin containing luting cements Corn starch
for posts. Zinc eugenate gets decomposed by water Lecithin
through a continuous loss of the eugenol. This makes • Advantages: Easy to mix, excellent lubrication, does not
ZOE a weak, unstable material. So, it cannot be used stain the tooth structure.
for retrofillings placed apically through a surgical • Disadvantages: Rapid setting time. It sets rapidly
approach. specially in presence of moisture.
Obturation of Root Canal System 291
Fig. 16.11 Tubli-Seal root canal sealer (Courtesy of Sybron Endo) Fig. 16.12 Sealapex root canal sealer (Courtesy of Sybron Endo)
292 Short Textbook of Endodontics
AH-26
It is a slow setting epoxy resin that releases formaldehyde
on setting, the highest amount being released in the
freshly mixed sealer and amount goes down after 48 hours. Fig. 16.13 Resin-based sealer-AH plus (Courtesy of Dentsply)
Obturation of Root Canal System 293
Glass Ionomer Sealers Such as EndoRez, EZ Fill and MetaSeal have also been
marketed to improve the sealing ability and bond strength
• Has dentin bonding property. to dentin.
• Disadvantages: If retreatment is required, its removal is
very difficult. Dentin Bonding Agents
• A commercially available Endodontic Glass Ionomer
sealer is Ketac-Endo (3M/ESPE). Such as Scotchbond, Gluma have been tried as root canal
sealers. There was dramatic improvement in the quality
Medicated Sealers of sealing root canals using dentin-bonding agents. But
the problems associated with these sealers would be, first
• Medicated canal sealer containing iodoform for the preparation of dentin has to be done to remove all
antibacterial purpose to be used with medicated gutta- the smear layer, especially from apical third of the canal.
percha. Second obstacle is radiopacity. If radiopaque metal salts
are added to the adhesive, it might affect polymerization. All
of the bonding agents are technique-sensitive. They do not
polymerize in the presence of moisture. Delivery system is
also the problem for its placement in the canal. Also, their
removal from canal is very difficult in case of a failure.
A mind-map to remember all points of root canal sealers
is given in Figure 16.15.
tissue, debris and bacteria, “Smear layer” which is present HOW TO DO OBTURATION/WHICH ARE
obstructs the dentinal tubules. Smear layer created THE DIFFERENT TECHNIQUES OF DOING
by instrumentation (inorganic) and due to chemical
OBTURATION?
composition of dentin (organic) may interfere with the
adaptation of filling materials to the canal wall. If all the Obturation Technique Using Silver Points
dentinal tubules are opened up by removing the smear layer, • Silver cones had been used for obturation in the past.
it will provide a better seal by allowing the sealer or filling • Method:
material to penetrate the dentin. – Dry the canal.
17% ethylene diamine tetra-acetic acid (EDTA) can be – Select a silver cone of the same size as last file used
used to remove the smear layer before the obturation. to shape the canal (Master Apical File) and cut off its
Obturation of Root Canal System 295
butt end to give it proper length. Sterilize and insert Classification of different obturation methods (Ingle’s
in the canal. Endodontics, 5th edn., p.598) is given in the Flow chart 16.1
– Take radiograph to confirm the length. and they are explained in detail as follows:
– Coat the canal walls with sealer.
– Carry the cone into the canal with sterile cotton pliers Solid Core Gutta-percha with Sealants
or stieglitz forceps until it fits snugly.
– Clean the pulp chamber and fill it with temporary
Cold Gutta-percha Points
cement.
Figure 16.16 shows radiograph showing obturation Lateral Compaction of Gutta-percha
with silver points. It is the most commonly used technique of obturation and
The use of Silver points for obturation is now has long been the standard against which other methods of
considered to be below the standard of care. obturation have been judged.
Other Obturation Techniques Principle: This technique involves first placing a sealer lining
in the canal, followed by a measured primary gutta-percha
Currently, most root canals are being filled with gutta- cone, that in turn is compacted laterally by a plugger-like
percha and sealers. The use of gutta-percha for obturation tapering spreader used with vertical pressure in order to
of canals is due to its property of ‘flow’ or ‘plasticity’. When make room for additional accessory cones. The final mass of
force is applied to gutta-percha, it becomes compacted and gutta-percha points is severed at the canal’s coronal orifice
it tends to flow away from a force directed at its mass. using a hot instrument and final vertical compaction is done
with a large plugger.
There are different methods for obturation using gutta- Lateral and vertical apical pressure compacts the gutta-
percha which can be classified based on: percha and makes it flow into the root canals.
• Direction of compaction: Lateral or vertical compaction
• Temperature of gutta-percha: Cold or warm (plasticized). Criteria for lateral compaction technique: (in canal
preparation and instrument selection)
Two basic procedures of obturation are: Lateral condensation compaction is the obturation
1. Lateral compaction of cold gutta-percha technique of choice if the following criteria are fulfilled:
2. Vertical compaction of warmed gutta-percha. Other • The final canal shape should be continuous taper
methods are variations of warmed gutta-percha. • In the apical area, it should be parallel, matching the
For each of the above techniques, you must know the taper of the spreader/plugger
principle, the stepwise method to perform the technique, • The spreader must reach within 1–2 mm of working
advantages and disadvantages. length
• An apical stop must be created, to resist apically directed
condensation
• The gutta-percha cones used as accessory cones must
be smaller in diameter than the spreader/plugger.
instrument used at the apex. It should be tested in place Pain could also occur if pulp remnants are still
and confirmed radiographically. present in the root canal and it is of much greater
Sterilization of gutta-percha using 5.25% NaOCl. intensity than the pain from periapical tissue.
Methods to determine the proper fit of the master cone Granulation tissue does not produce any pain.
include: – Radiographic test : After the visual and tactile
– Visual test: The gutta-percha point is measured and tests, the position of the master cone is finally
grasped with cotton pliers at a position within 1mm checked with the radiograph. On the radiograph,
of the prepared length of the root canal. The point is the point extending to within 1mm from the tip of
then grasped 1mm back and again pushed apically. the preparation should be seen. The master cone
If point can be pushed beyond the working length radiograph (as shown in Figure 16.17) helps to
(apex), then a larger size cone is used or the same evaluate whether the working length of the tooth was
cone is cut from its tip. The point is retried in the correct, whether instrumentation followed the curve
canal until it goes to the correct position by trial and of the canal and whether any perforation occurred.
error. If the primary point appears to be overextended,
– Tactile test: It determines whether the point tightly then it should be shortened from the fine end and
fits the canal. If the apical 3–4 mm of the canal have then returned to the correct position. If the primary
been prepared with near parallel walls, some degree point appears to be underextended, then a smaller
of force is required to seat the point, and once in size gutta-percha point is selected or a new file
position, a pulling force is required to dislodge it. of the same number is selected and the canal is
This is known as“Tug-back.” If the point fits loosely reinstrumented to full working length until the file
in the canal, next larger size point should be tried or is loose in the canal and the point is reseated and
the point can be cut from its tip and retried in canal radiograph taken again.
until it fits the canal correctly by trial and error. - Drying the canal: To dry the canal, an absorbent
– Patient’s response: Patients who are not anesthesized paper point is placed in the canal to absorb
during the treatment of a nonvital pulp or during moisture or blood that might accumulate.
the second appointment of vital pulp, may feel pain - Mixing and placement of sealer: A sterile slab and
when gutta-percha penetrates the apical foramen. spatula is used in case of powder-liquid system to
Obturation of Root Canal System 297
Step-wise Method
• The largest file used in the canal at the working length Fig. 16.17 Master cones placed in the canals of mandibular second
or the last file that was used to shape the apical part of molar tooth (Courtesy of Dr Shivani Bhatt)
the root canal is called as the Master Apical File (MAF).
First step is to select a standardized gutta-percha
cone as per the master apical file. This cone will be called
as the primary cone or master cone.
An alternative is to use a conventional cone of
appropriate taper and to adapt it by cutting small
increments from the tip.
• Insert the master cone into the root canal to the
established working length. It should fit snugly and
should resist removal (“tug-back”).
• Take a radiograph to determine the apical and lateral fit
of the primary cone. Figure 16.17 shows radiograph of
mandibular second molar with primary cone in each of
the canals.
On the radiograph:
– If the primary cone extends beyond the working
length and protrudes through the apical foramen,
then select a larger cone and adapt it in the canal or Fig. 16.18 Paper points which are caliberated, color-coded and of
the size and shape of the ISO standardized instrument (Courtesy of
cut off the tip so that the reinserted primary cone fits Dentsply)
snugly, has “tug back” and seals apically.
– If the initial fit of the primary cone fails to go to
the prepared length or appears 2–3 mm short of master cone. Figures 16.21A to F demonstrates the
the apex, then select a smaller cone and adapt it or following steps.
reprepare the canal to the corrected length, and then • Apical half of the primary cone is coated/buttered with
adapt the primary cone, and confirm its placement the sealer cement and the cone is carefully replaced in
radiographically. the canal.
• After the appropriate primary cone is selected and • Select an appropriate size spreader that can be placed
adapted, remove it from the canal and disinfect it by within 1–2 mm of the working length and insert it along
placing it in sodium hypochlorite for 1 minute followed side the primary cone applying gentle pressure laterally
by rinsing it with alcohol or wiping it with cotton swab and apically.
dabbed in clinical spirit. Figure 16.19 shows the photograph of finger-held
Irrigate the canal and dry it with paper points. Figure spreader no. 30 and figure 16.20 shows the photograph
16.18 shows photograph of the paper points. of hand-held spreader.
• Coat the walls of the canal with a thin layer of sealer It has been found that deep spreader penetration
cement using a lentulospiral, reamer, file or end of the minimizes apical leakage and percolation.
298 Short Textbook of Endodontics
D E F
• It has been found that: methods can be used such as Tailor made gutta-percha
– Finger spreaders provide better tactile sensation and roll (explained later). Warm gutta-percha techniques are
have lesser potential to induce fractures in the root more suitable for filling immature canals and apices.
as compared to the hand-held spreader. • Tubular canals: Tubular canals have large apical opening
Figures 16.18 and 16.19 show the photographs with nonconstrictive terminus. It may be best filled
of the finger spreader and hand-held spreader with a coarse primary gutta-percha cone, that has been
respectively. blunted by cutting off the tip or a tailor-made point
– Nickel-Titanium spreaders provide reduced stress can be used. Warm gutta-percha techniques may be
due to increased flexibility and provide deeper preferred.
penetration as compared to stainless steel spreaders • Tailor-made gutta-percha roll: In case of immature canal
in curved canals. with blunderbuss apex or tubular canal, the largest
• Deeper spreader penetration minimizes apical leakage gutta-percha point may be still loose in the canal. So,
and percolation. a tailor-made gutta-percha roll is preferred by heating
• Standardized GP cones have lesser taper than a number of large gutta-percha cones and combining
conventional GP cones. So, when it is used as master them, butt to tip, until a roll has been developed much
cone, it permits deeper spreader penetration. the size and shape of the canal. After preparing the roll, it
must be chilled with a spray of ethyl chloride or ice water
Advantages to stiffen the gutta-percha before fitting into the canal.
• Widely used method for obturation that can be used in
most clinical situations. Chemically Plasticized Cold Gutta-percha
• Provides for length control during compaction.
This technique is a modification of lateral compaction
Disadvantages obturation that uses a solvent to soften the primary gutta-
• This technique does not produce a homogeneous mass. percha point to ensure that it will better conform to the
• It may not produce a dense filling. There is possibility of aberrations in apical canal anatomy.
voids between the filling and canal wall and within the Solvents such as chloroform, eucalyptol and xylol
filling. plasticize the gutta-percha and this plastic mass can be
• It may not fill the canal irregularities well, when forced into the canals.
compared with warm vertical compaction. Gutta-percha plasticized using chloroform is called
• There is potential for vertical root fracture if excessive chloropercha.
forces (of more than 2.5–3 kg) are applied. Gutta-percha softened in warm oil of eucalyptus is called
eucapercha.
Variations of Lateral Compaction It is not practically possible to use this technique for
• Curved canals: Roots may have mesial or distal curvature, obturation as the solvent evaporates over a period of time
which is visible on radiograph or buccal or lingual causing shrinkage and voids in obturation.
curvature which is not visible on radiograph. Some teeth Usually, only the tip of the gutta-percha point is dipped
have severely curved, dilacerated or bayonet canals. In in the solvent and that too just for one second as two to three
case of lateral compaction of primary gutta-percha point dips will cause serious leakage.
(master cone) in a curved canal, more vertical force will Sealers such as Calcibiotic Root Canal Sealer and Wach’s
have to be exerted against it as the spreader will tend to sealer contain the solvent-oil of eucalyptol and Canada
catch into gutta-percha point, forcing it apically. In such balsam respectively.
cases, more flexible spreaders such as Nickel-Titanium
spreaders are preferred to reach within apical 1 mm and Canal-warmed Gutta-percha
distribute the forces evenly in curved canals. Warmed
or thermoplasticized gutta-percha techniques may be Warm Vertical Compaction Technique
preferred in curved canals. Also called as Schilder technique.
• Immature canals and apices: Blunderbuss apex of • Principle: Makes use of vertical force combined with the
an immature tooth makes obturation complicated. applied heat in order to drive the gutta-percha apically
Apexification is the technique of choice that creates an and laterally.
apical stop, before carrying out obturation. Apexification This technique was introduced by Schilder with
is explained in detail in Chapter 27 Pulp Therapies. If an objective of achieving 3-dimensional filling of the
apexification fails or is inappropriate, then other special radicular space. He recommended obturation with
300 Short Textbook of Endodontics
A B C D E
F G H I J
Figs 16.24A to J (A) Heated plugger used to remove gutta-percha from above the coronal portion of master cone gutta-percha; (B) Room
temperature plugger used to vertically compact the plasticized material apically; (C to E) Alternate application of plugger and condenser until
plasticized gutta-percha seals the accessory canals; (F and G) Backfilling of canal: After apical compaction,segment of gutta-percha placed in
the canal and heat applied laterally; (H to J) Backfilling of the remaining coronal portion of the canal
– The pluggers used in this technique are rigid which #0.12 tapered pluggers (as shown in Figure 16.27) having a
cannot penetrate to the required depth, especially in diameter of 0.5 mm and an electric heat carrier, System B
case of curved canals and ribbon-shaped canals. unit. The System B unit is a new heat source that monitors
the temperature at the tip of the heat-carrier pluggers and
Continuous Wave Compaction Technique delivers a precise amount of heat for an indefinite time.
(System B Compaction) Figure 16.28 shows the photograph of the Buchanan hand
Buchanan introduced a variation of Warm Vertical pluggers.
Compaction technique called as the Continuous Wave
Compaction technique, which is faster and more accurate. Tapered pluggers GP cones
# 0.06 is used to approximate Fine conventional GP cone
Principle # 0.08 is used to approximate Fine-medium GP cone
Makes use of cones that are manufactured to mimic the
# 0.10 is used to approximate Medium GP cone
tapered preparation that is achieved with the use of Nickel-
# 0.12 is used to approximate Medium-large GP cone
Titanium rotary instrument by using #0.06, #0.08, #0.10 and
302 Short Textbook of Endodontics
These pluggers are consistent with Greater Taper points consistent with the size of the Greater Taper
instruments. instruments).
• Set the system B unit to 200oC in touch mode. Figure
Step-wise Method 16.30 shows photograph of the System B cordless unit.
• Insert the appropriate master cone in the canal and • Activate the appropriate size plugger to remove the
along with that a corresponding tapered plugger is excess coronal material.
prefitted to fit within 5–7 mm of the canal length. (Figure • Room temperature plugger of appropriate size is
16.29 shows the photograph of Autofit gutta-percha used to compact the gutta-percha in the canal while
Obturation of Root Canal System 303
Advantages
• Provides good apical seal
• Can effectively fill lateral and accessory canals
• Saves time, quick procedure (15–20 seconds)
• Postspace can be created easily.
Disadvantages
• Chances of extrusion of obturation beyond the apex
• Additional equipment may be required to backfill the
coronal portion of the canal.
– Take a radiograph to check the position and fit of the Warm Lateral/Vertical Compaction Technique (Hybrid
condensed section of gutta-percha. Technique)
– Take another section of gutta-percha 3–4 mm long Hybrid technique combines lateral compaction technique
dipped in eucalyptol and warm it over a flame and + thermoplasticized GP technique.
add it to the previous section in the canal and apply Begins with lateral compaction to achieve a good apical
vertical pressure. seal. After placing master cone and several accessory cones,
– The process is repeated to fill the entire canal as use a hot plugger to sear off the GP points at the length of
shown in Figure 16.32D. 4–5 mm from the apex.
If post and core restoration is to be done, only the first Then, light vertical compaction is applied to restore the
or apical section of gutta-percha is sufficient to obturate integrity of the apical plug of gutta-percha.
the canal in which the remaining canal is used for post- Remaining canal is then back-filled with the
placement. thermoplasticized gutta-percha injection.
• Recent development: Instead of laboriously adding
sections of gutta-percha, backfilling may be done Endotec Device II
with thermoplasticized gutta-percha using the Obtura Considering the ease and speed of lateral compaction
II gutta-percha system, in which the canals can be technique and superior density achieved using vertical
backfilled, up to 10 mm in a single increment. compaction of warm gutta-percha, Martin developed
• Advantages: This technique seals the canal apically and Endotec II device that incorporates the qualities of both
laterally. techniques.
• Disadvantages: Endotec II device brings about warm lateral compaction
– Time-consuming technique of gutta-percha into the prepared canals in the form of a
– Sections of gutta-percha may be difficult to retrieve solid homogeneous mass.
if the canal is overfilled. Various tapers and tip diameters of Endotec II tips are:
– Condensing sections of gutta-percha into a Tapers/Tip diameters
homogenous mass may be difficult. As a result, voids # 0.02/30
may occur in between the sections. # 0.05/30
A B C D
Figs 16.32A to D Sectional method of compaction: (A) A gutta-percha cone of approximate size of prepared canal placed in canal and apical
section of length 3–4 mm is cut; (B) Heated plugger with mounted section of gutta-percha is inserted in the canal to within 3–4 mm of the
apex; (C) Inserted section of gutta-percha in apical portion of canal; (D) Entire canal filled
Obturation of Root Canal System 305
core devices of ISO size 15–60. They resemble the latch- • As the apical portion of the canal is filled, the needle
type Endodontic drills and are coated with alpha-phase backs out of the canal.
gutta-percha. After placing in the prepared root canal • Unheated plugger dipped in alcohol is used to compact
with the sealer, it is spun in the canal using a regular low- gutta-percha. Continue compaction until gutta-percha
speed, latch-type handpiece. Frictional heat generated cools and solidifies.
plasticizes and compacts the gutta-percha by the design
of the Quick-fill core. After compaction, compactor Advantages
may be removed while it is spinning or left in place and • Provides good adaptation to canal walls.
separated in the coronal cavity with an inverted cone bur. • Quick, saves time.
• Ultrasonic plasticized gutta-percha technique: Moreno
described that the ultrasonic instrument can be used to Disadvantages
plasticize gutta-percha. He used the friction of ultrasonics • Lack of length control: Both overextension and
plus hand or finger pluggers for condensation. It was underextension have been found to occur.
found that the heat generated by this technique is safe • In narrow preparation, it may be difficult to reach deep
and effective. However, it is not commonly used. in the canal.
• Special care needs to be taken while introducing the
Thermoplasticized Gutta-percha needle into the canal as it is hot and should not touch
patient’s oral tissues.
Thermoplasticized Injectable Gutta-percha Techniques
• Principle: This technique involves application of heat Inject-R Fill backfilling technique: It uses a miniature-
to gutta-percha outside the tooth to soften it and this sized metal tube containing conventional gutta-percha
softened gutta-percha is then injected into the canal. and plunger and allows for delivery of a single backfill
– Examples of thermoplastic injection techniques: injection of gutta-percha once the apical segment of the
Obtura II System and Ultrafil 3D system are canal has been obturated. The apical segment of the canal
examples. can be obturated using any of the techniques such as
lateral compaction, traditional warm vertical compaction
or System B.
Principle
– Mark the carrier at correct working length and place • The Apical GP Plug has same ISO size as the Lightspeed
it in the heating device (Thermafil oven) to heat it to “Master Apical Rotary” (MAR).
appropriate temperature for 10 seconds. • The canal is coated with a sealer and the Apical GP Plug
– Retrieve it and rapidly insert it into the canal. carrier is inserted into the canal.
– Take a radiograph to confirm the position of the • Once placed, the carrier is removed, leaving behind an
carrier. apical plug of gutta-percha.
– Allow gutta-percha to cool for 2–4 minutes. Then • The remaining portion of the canal is back-filled either
resect the carrier, few millimeters above the canal by using a Simplifil syringe or other method such as
orifice using round or inverted cone bur. Obtura II.
– Compact the coronal gutta-percha vertically. • Advantages:
• Advantages: – It helps to conserve dentin due to Light-Speed
– Facilitates flow of gutta-percha apically and into instrumentation technique (less flaring).
lateral and accessory canals. – It eliminates additional internal forces as it does not
– Very less amount of sealer is needed. use any additional spreader or plugger to compact
• Disadvantages: the apical plug.
– Possibility of extrusion of material beyond the apex. – No carrier is left in the canal.
– It is difficult to prepare the postspace as the plastic
core retains in the canal. Dentin-chip
Successfil • This new technique is being studied that will provide a
• Successfil obturators have either titanium carriers or biological seal rather than mechanochemical seal and
radiopaque plastic carriers. will stimulate osteogenesis or cementogenesis as well.
• It is used in conjunction with Ultrafil 3D system. • After root canal preparation, when the dentin is no
• After placing the carrier in the canal to the correct longer contaminated, a Gates Glidden drill or Hedstrom
working length, gutta-percha around the carrier is file is used to produce dentin powder in the central
compacted with plugger. portion of the canal.
• Then the carrier is resected few millimeters above the • A premeasured file one size larger than the last apical
canal orifice with a bur. enlarging instrument is used to pack the dentinal chips
at the apex. About, 1–2 mm of dentinal chips should
Apical-Third Filling block the apical foramen.
• The resistance to perforation is tested using no. 15 or 20
file to check the completeness of density of the apical
Lightspeed Simplifill
plug.
• Used in canals prepared with Lightspeed instruments. • The final gutta-percha is then compacted against that
• Uses a stainless steel carrier to place and compact 5 mm apical plug.
of gutta-percha into the apical portion of a canal. • Advantages: It prevents overfilling and leads to quicker
healing, minimal inflammation and apical cementum
deposition.
Calcium Hydroxide
• Calcium hydroxide has been widely used to bring about
apexification in case of immature teeth with open apex.
In canals with closed apex also if calcium hydroxide is
used, cementification occurs.
• Calcium hydroxide can be placed as an apical plug in
either dry or moist state.
• It acts as a stimulant to cemental growth. It also acts as
a barrier to extrusion of well-compacted gutta-percha
Fig. 16.33 Thermafil obturator obturation.
308 Short Textbook of Endodontics
– This is generally acceptable and may be well- It is recommended that the postobturation coronal
tolerated in the periradicular tissues in case of restoration such as bonded core built-up material
biocompatible sealers and various studies and be placed as soon as possible after obturation and
research shows that it does not affect the osseous preferably at the obturation appointment itself to
repair and healing. prevent any coronal leakage.
– In fact it is believed that the apical puff is an indicator • It has been found that microleakage can occur through
that the gutta-percha has been densely packed into well-obturated canals if proper seal has not been
the apical preparation and that all of the aberrations, achieved with an appropriate coronal restoration. Thus,
as well as lateral and accessory canals of the root coronal seal plays an important role in maintaining the
canal system have been cleansed and filled. Figure apically sealed environment.
16.35 shows the postoperative radiograph of a Preventing coronal microleakage has significant
mandibular molar showing “sealer puff”. impact on long-term success of Endodontic therapy.
• Overextension indicates that the obturating material The importance of coronal seal by means of an
has extended and has got extruded beyond the apical appropriate coronal restoration placed over the canal
foramen but with the caveat that the canal has not been obturation is to prevent microleakage and subsequent
adequately filled and the apex has not been sealed. reinfection of the root canal system and the periapical
Thus, overextension may be associated with underfilled area for a successful Endodontic treatment.
canal, i.e. the canal may not have been adequately filled • Microleakage has been found to occur even with the
within its confines. permanent coronal restorations such as amalgam or
Leakage
• Poor apical seal causes apical leakage, that is leakage
between root canal and periapical tissues.
• Poor coronal seal causes coronal leakage, that is leakage
from the oral cavity into the root canal.
Leakage adversely affects healing and repair and is the
main cause of Endodontic failures.
A B C
Figs 16.34A to C Few examples of underextended obturation
310 Short Textbook of Endodontics
17
CHAPTER
used in Endodontic
Treatment
This chapter explains how Root canal treatment can be made comfortable, pain-free and successful
for the patient by appropriate management of patient’s fear, anxiety, pain and elimination of infection,
when present. It gives an overview of various drugs used in Endodontics.
You must know
• How to Manage Fear and Anxiety in an Endodontic Patient?
• Which are the Drugs or medicaments used in Endodontics?
HOW TO MANAGE FEAR AND ANXIETY Examples of iatrosedative techniques include hypnosis,
IN AN ENDODONTIC PATIENT? audioanalgesia, biofeedback, etc.
→ Nonbenzodiazepines: Zolpidem
Zaleplon
To be taken – The night prior to the planned appoint
ment to ensure restful night’s sleep
– I n the morning, 1 hour prior to the
scheduled dental visit.
• Parenteral routes:
– Intravenous sedation → IV conscious sedation
with benzodiazepines
such as Midazolam
and/or Diazepam
– Intramuscular sedation → Not safe and controll
able, so generally not
recommended for use
in dentistry
Fig. 17.1 Different kinds of fear that an Endodontic – Intranasal sedation → Not as controllable
patient may have as IV route, not
recommended for use
• Making local anesthetic injections comfortable and in dentistry.
atraumatic by
– Application of topical anesthetic at the site of
WHICH ARE THE DRUGS OR MEDICAMENTS
injection to avoid even the pain from the needle
prick. USED IN ENDODONTICS?
– Slow administration of local anesthetic solution.
Pharmacosedation
In few cases, behavioral intervention may not be effective
and pharmacologic management of anxiety needs to be
carried out.
This includes use of sedatives and tranquillizers that
can calm the patient without producing sleep, but may
cause drowsiness to some extent. They act by depressing
the central nervous system (CNS) and decreasing cortical
excitability decreasing the patient’s awareness and
distracting their minds from the dental procedure.
Minimal, moderate or deep sedation can be achieved For Management of Anxiety
as per the need with the help of drugs used for conscious
sedation. Inhalation, oral and parenteral routes such as Antianxiety drugs such as sedatives (discussed already).
intramuscular, intravenous and intranasal are the routes
of administration of CNS-depressant drugs. Inhalation and
For Effective Pain Control
oral routes are commonly used.
Local Anesthetics
Drugs Used for Sedation
Root canal treatment will not be possible without achieving
• Inhalation sedation → Uses N2O-O2 combination effective pain control. Effective local anesthesia helps
• Oral sedation → Benzodiazepines: Alprazolam achieve profound pain control.
Diazepam
Lorazepam Local anesthetic technique should be made “painless” and
Midazolam comfortable for the patient by:
Flurazepam • Use of topical anesthetics at the injection site.
Drugs or Medicaments used in Endodontic Treatment 313
Mandibular Anesthesia
For the mandibular anterior teeth, infiltration technique of
anesthesia can be quite effective. A combination of labial
and lingual infiltration is to be administered.
For the mandibular posterior teeth, inferior alveolar
nerve block has to be administered. But it is not always
successful due to various factors such as inaccurate
positioning of needle, improper technique, accessory
path of innervation, tooth with preoperative pain and
inflammation, needle deflection, cross innervation, etc.
• Onset: Onset of pulpal anesthesia with infiltration occurs
in 5–7 minutes and with inferior alveolar nerve block
occurs in 10–15 minutes in most cases.
• Duration: Effect of anesthesia lasts for approximately
1–2½ hours with 2% lidocaine with 1:1,00,000
epinephrine.
When IANB is not successful, alternate or supplemental
injection techniques are indicated.
Alternative Techniques
Such as Gow-Gates and Vazirani-Akinosi do not replace
the conventional inferior alveolar nerve block but may be
314 Short Textbook of Endodontics
indicated in certain selected cases. For example, Vazirani- anesthetic delivery system such as Wand or
Akinosi block for limited mandibular opening, incisive nerve CompuDent®.
block for premolar teeth. • Intraosseous injection:
– It delivers the local anesthetic solution directly
Supplemental Techniques into the cancellous bone adjacent to the tooth to
be anesthesized. Figure 17.4 demonstrates the
After an inferior alveolar nerve block, when profound lip intraosseous injection.
numbness has developed but patient still experiences – Commercially available intraosseous systems
pain upon Endodontic access, supplemental injection include:
techniques are indicated rather than repeating the IANB - The stabident system
which are follows: - The X-tip system
• Intraligamentary injection: - The intra-flow system
– Traditional or pressure syringe can be used with 25, – Drawback is moderate to severe pain during
27 or 30 gauge needle. perforation and deposition of solution especially
– Injection under strong back pressure to force the in teeth with irreversible pulpitis as compared to
solution into marrow spaces is the most important asymptomatic teeth.
factor for anesthetic success with intraligamentary – Site of injection is distal to the tooth to be anesthetized
injection. except for maxillary and mandibular second molars,
– About 0.2 mL of solution can be delivered with each where the site of injection is mesial to the tooth.
mesial and distal injection. Figure 17.3 demonstrates Perforation is made in attached gingival or alveolar
the intraligamentary injection. There is immediate mucosa where the cortical bone is thinner and allows
onset of anesthesia and if still not adequate, injection at a site equidistant between adjacent root
reinjection is indicated. structures.
– The drawback of this technique is moderate to – Onset of anesthesia with intraosseous injection is
severe pain during injection especially in teeth with almost immediate.
irreversible pulpitis as compared to normal teeth – Transient tachycardia has been reported to occur for
and possibility of postoperative pain that may last 3–4 minutes after intraosseous injection.
for 14–72 hours after injection. – There is possibility of moderate pain on
– Recent technology for intraligamentary supplemental a postoperative day but less as compared to
injection makes use of computer-assisted local intraligamentary injection.
– There can be swelling or exudate for few weeks after Most commonly used primary injection technique for
injection. maxillary teeth anesthesia is infiltration with 1.8 mL of 2%
• Intrapulpal injection: lidocaine with 1:1,00,000 epinephrine.
– In case of mandibular posterior teeth, in spite Onset of anesthesia occurs in 5–7 minutes and duration
of inferior alveolar nerve block and repeated of action is approximately 20–30 minutes for anterior teeth
supplemental intraosseous injections, if pain persists and 30–45 minutes for posterior teeth.
during Endodontic access, the intrapulpal injection It has been found that increasing the volume of 2%
is indicated. Figure 17.5 demonstrates intrapulpal lidocaine with 1:1,00,000 epinephrine to 3.6 mL can increase
injection. the duration of pulpal anesthesia.
– Onset of anesthesia is immediate and the technique • Alternative maxillary injection techniques:
does not require any special syringe or needles. – Posterior superior alveolar (PSA) nerve block: To
Duration of action is less (about 15–20 minutes) anesthetize some first molars and all second and
– But the major drawback is moderate to severe third molars.
pain during injection as the needle placement and – Infraorbital nerve block: To anesthetize first and
injection are directly into a vital and very sensitive second premolars and the lip, but not the central or
pulp. lateral incisors.
– It produces profound anesthesia if it is given under – Second division nerve block: (High tuberosity
backpressure. approach): To anesthetize the pulps of molar teeth
– If the anesthetic solution is deposited passively and about 50% of the second premolars.
into the pulp chamber, the solution will not diffuse – Palatal-anterior superior alveolar (ASA) nerve
throughout the pulp and hence is ineffective. block: To anesthetize maxillary incisors and canines
bilaterally. Anesthetic solution is deposited into the
Maxillary Anesthesia incisive canal.
– Anterior middle superior alveolar (AMSA) nerve
Clinically, it is easier to achieve maxillary anesthesia than block: To anesthetize maxillary central and lateral
mandibular anesthesia. incisors, canine and first and second premolars.
Anesthetic solution is deposited palatally at a point
that bisects the premolars and lies halfway between the
midpalatine raphe and the crest of free gingival margin.
Evaluation of Anesthesia
To confirm whether anesthesia has acted, following
methods are used:
• Questioning the patient:
– Does the area feel numb?
– Do you feel any kind of heaviness or tingling?
• Using a sharp explorer for soft-tissue testing. There will
be no mucosal response if anesthesia has acted.
The pulpal anesthesia of the tooth under treatment is
evaluated:
– By application of cold refrigerant (cold test) or
– By using an electric pulp tester.
If profound anesthesia is not achieved after an
initial injection, then supplemental injection is
Fig. 17.5 Intrapulpal injection indicated.
316 Short Textbook of Endodontics
Opioid Analgesics
• They are potent analgesics effective for moderate to
severe pain.
• Mechanism of action: Opioids activate mu receptors that
• Ibuprofen is considered the prototype of contemporary are located at important sites in brain
NSAIDS. It can inhibit both COX 1 and COX 2 enzymes, ↓
so it can be termed as “mixed COX” inhibitor, more so, Inhibition of transmission of nociceptive signals from
that of COX 1 enzyme. trigeminal nucleus to higher brain centers.
• Blockade of COX 1 can have gastrointestinal adverse • Opioids are not anti-inflammatory.
effects such as ulcers. Blockade of COX 2 can have • Adverse effects: Nausea, dizziness, drowsiness,
cardiovascular adverse effects such as thrombotic constipation, respiratory depression, tolerance and
events. dependence with chronic use.
• NSAIDs are very effective in managing pain of • Due to numerous side effects, opioids are usually
inflammatory origin. used in combination with other analgesics to manage
• Adverse effects: Endodontic pain. Opioid analgesics are used in
– Ceiling effect that limits the maximal level of combination with acetaminophen, aspirin or ibuprofen.
analgesia
– GIT side effects Corticosteroids
– CNS side effects (Dizziness, headache) • Not routinely used.
• Contraindications: NSAIDs are contraindicated in • Mechanism : Glucocorticoids reduce the acute
patients with ulcers and aspirin hypersensitivity. inflammatory response
Drugs or Medicaments used in Endodontic Treatment 317
– by inhibiting the formation of arachidonic acid, and draining sinus tract or localized fluctuant swellings,
– by suppressing vas odilatation, migration etc. can be effectively managed without the use
of polymorphonuclear (PMN) leukocytes and of antibiotics. They can be effectively managed by
phagocytosis analgesics and combination of
↓ – Appropriate Endodontic procedure along with
Thus, they block the cyclooxygenase (COX) and lipo- – Use of intracanal medicament in few cases and
oxygenase (LOX) pathways – Occlusal reduction (Bite relief )
↓ Systemically administered antibiotics cannot
Blocking synthesis of prostaglandins and leukotrienes substitute timely Endodontic treatment. Chemo
↓ mechanical debridement of the infected root canal
Pain control system and incision and drainage if there is swelling,
• Steroids have been used in the past as: usually begins the healing process in case of a normal
– Pulp capping agent healthy patient. Incision and drainage provides pathway
– Intracanal medicament alone or in combination with for removal of inflammatory mediators and helps
antibiotics/antihistaminics prevent further spread of cellulitis.
– Systemic administration to decrease pain and • Use of antibiotics in Endodontics is controversial in
inflammation in Endodontic patients certain cases due to various reasons such as:
• Steroids have been found to be more effective in pain – Overprescribing of antibiotics, in cases where not
from pulpal necrosis with associated radiolucency indicated can result in bacterial resistance and
compared to pain from irreversible pulpitis because patient sensitization.
necrosis with periapical radiolucency has a more – Sometimes, severe pain may be from a vital tooth
complex chronic inflammatory process. where bacteria are not a causative factor, where
• Dosage: 6–8 mg of dexamethasone or 40 mg of methyl- antibiotics are not needed.
prednisolone can be given by an intraoral IM injection
or an intraosseous injection for the adult patient for Antibiotics commonly used in dentistry
significant post-treatment pain relief. • Penicillins:
– Effective against both facultative and anaerobic
For Prevention or Elimination of Infection microo rganisms associated with polymicrobial
Endodontic infections.
Antibiotics – Mechanism of action: Inhibition of cell wall synthesis
during multiplication of microorganisms. Exerts
Not all Endodontic cases require antibiotics. bactericidal action.
• Conditions that require adjunctive antibiotics: – 1g of penicillin VK can be orally administered
1. a. Cases with show signs of systemic involvement followed by 500 mg every 4–6 hours.
such as fever, malaise, lymphadenopathy, – Amoxicillin 1 g—as a loading dose can be very
trismus, etc. effective to treat infections followed by 500 mg every
Acute alveolar abscess is the condition which 8 hours.
may show such systemic involvement and • Clavulanate:
will need antibiotic treatment in addition to – It causes competitive inhibition of beta-lactamase.
debridement of root canal and drainage of any – Clavulanate + amoxicillin (Augmentin) combination
accumulated purulence. is very useful in Endodontic infections. This
b. Progressive infections—increased swelling, combination is effective in immunocompromised
cellulitis, osteomyelitis. patients also.
c. Persistent infections • Erythromycin and other macrolides:
2. Prophylactic antibiotics are prescribed in medically – Mainly used in patients allergic to penicillin
compromised patients to prevent infection. – Not effective against anaerobes associated with
3. Surgical Endodontics Endodontic infections
• Conditions that do not require adjunctive Endodontics: – Clarithromycin and azithromycin are other
Most of the infections of Endodontic origin, such macrolides with some advantages over erythromycin.
as symptomatic irreversible pulpitis or apical – Dosage: Clarithomycin 250–500 mg every 12 hours
periodontitis, necrotic teeth with radiolucency or a for 6–10 days
318 Short Textbook of Endodontics
Azithromycin loading dose: 500 mg followed by Prophylactic antibiotics are recommended for both non-
250 mg daily. surgical and surgical Endodontic procedures in patients
– These antimicrobials can block the metabolism of with cardiac conditions who are at risk of developing
anticoagulant drugs like warfarin causing serious bacterial endocarditis.
bleeding in patients undergoing anticoagulation
therapy. Intracanal Irrigants and Disinfectants
• Clindamycin: Such as sodium hypochloride, EDTA, chlorhexidine, etc. are
– Effective against both facultative and strict anaerobic the agents used during root canal treatment for debridement
bacteria associated with Endodontic infections and cleansing of infected root canal of all necrotic debris
– Dose is 600 mg loading dose followed by 300 mg and for removal of smear layer.
every 6 hours. Discussed in detail in Chapter 15: Disinfection of the
• Metronidazole: Root Canal System.
– Effective against anaerobic bacteria. A mind-map to remember the drugs used in Endodontics
– Can be combined with penicillin to treat severe or is given in Figure 17.6.
persistent Endodontic infections.
– Patients taking metronidazole should not consume BIBLIOGRAPHY
alcohol during therapy and atleast 3 days afterward
to prevent disulfiram type of reaction. 1. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis:
Mosby; 2006. pp.597-9, pp.668-90, pp.691-723.
• Cephalosporins:Usually not indicated for treating 2. Grossman L, Oliet S, Del Rio C. Endodontic Practice, 11th edn.
Endodontic infections. Varghese publication; 1991.pp.1-18.
• Doxycycline: May be occasionally prescribed when the 3. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics, 6th edn.
above antibiotics are contraindicated. BC Decker Inc, Hamilton; 2008.pp.690-709.
• Ciprofloxacin : May be indicated in persistent
infections.
18
CHAPTER
This chapter tells you about the concept of single visit Endodontics (SVE), which has become quite
popular these days and guides you to the proper case selection for the same.
You must know
• What is Single Visit Endodontics?
• What is the Rationale for SVE?
• What are the Advantages and Disadvantages of SVE?
• What are the Possible Indications and Contraindications of SVE?
• What are the Factors to be Considered for Case Selection for Doing SVE?
• What has Held Back SVE?
Fig. 18.1 Mind-map to remember all factors to be considered for SVE case selection
8. Clinical symptoms: SVE cannot be done in case of acute WHAT HAS HELD BACK SVE?
symptoms such as severe pain, tenderness, swelling,
continuous hemorrhage or exudation. The fear of postoperative pain and the fear of failure of
9. Periapical pathology: Teeth with acute alveolar abscess SVE are the reasons why few clinicians prefer multivisit
or a chronic apical lesion visible on radiograph should approach over SVE. Also, lack of adequate time to do SVE
not be treated in single visit. Multiple appointments with and lack of skills and speed may hold back the clinicians
an intracanal medicament may be needed in such cases. from doing SVE.
Figure 18.1 shows a mind-map to remember all There is still ongoing controversy about SVE regarding
factors to be considered for SVE case selection. postoperative pain, flare-ups and healing rate after SVE as
Single visit Endodontics can be a beneficial treatment compared to multivisit approach.
modality provided there is:
BIBLIOGRAPHY
• Accurate diagnosis
1. Grossman L, Oliet S, Del Rio C. Endodontic Practice, 11th edn.
• Careful case selection Varghese Publication; 1991.pp.349-50.
• Adherence to standard Endodontic principles 2. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics 6, 6th edn.
• Clinician’s skill in technique. BC Decker Inc, Hamilton; 2008.pp.21-25.
19
CHAPTER
Endodontic Emergencies
and Midtreatment Flare-ups
This chapter describes in detail the various emergency conditions that may be encountered in
Endodontic practice, so that the clinician can identify them and provide prompt treatment because
prognosis of an emergency procedure depends on:
– Clinician’s ability to do correct diagnosis
– Clinician’s ability to deliver optimal emergency treatment.
You must know
• What is an Endodontic Emergency?
• What is Meant by the Terms ‘Hot Tooth’ and ‘ERCO’?
• How to make Correct Diagnosis in Case of Endodontic Emergencies?
• How do we Classify Endodontic Emergencies?
• Endodontic Emergencies in Detail
• Endodontic Emergencies before Treatment
• Interappointment Endodontic Emergencies
• Endodontic Emergencies after Treatment
WHAT IS AN ENDODONTIC EMERGENCY? emergency to control patient anxiety. The clinician must
As the name suggests, Endodontic Emergency is the accurately diagnose the origin of pain or other symptoms,
occurrence of severe pain or swelling or discomfort as quickly as possible and then attempt to provide speedy
of sudden onset associated with pathosis in pulp and and effective relief of symptoms.
periradicular tissues (Endodontic) or traumatic injuries, After all, for a clinician, effective pain relief builds up
which should be addressed immediately (Emergency) to good dental practice and also gives lot of job satisfaction.
give relief to the patient.
Endodontic Emergency can be defined as the condition WHAT IS MEANT BY THE TERMS
associated with severe pain and/or swelling caused by ‘HOT TOOTH’ AND ‘ERCO’?
pathosis in the pulp or periapical tissues or traumatic • ‘Hot tooth’ is the term used for the painful tooth and
injuries, requiring an unscheduled visit for immediate initial therapy for hot tooth refers to the treatment that
diagnosis and treatment. needs to be done to give relief from pain during an
It has been found that one-third of all dental emergencies emergency visit.
are Endodontic with ‘pain’ as the major symptom in most • The ERCO means emergency root canal opening, that
of them. is initiation of Endodontic treatment immediately to
An Endodontic emergency can be an unscheduled carry out pulpotomy or pulpectomy and even root canal
intrusion when the clinician is involved in his routine preparation in few cases.
practice. As the clinician sees the patient’s discomfort and Cases requiring an emergency root canal opening
apprehension, he may feel tempted to rush through the (ERCO):
diagnosis and provide prompt treatment. However, in no • Emergency-type pain from an odontogenic origin often
circumstances, the urgency of the situation precludes a comes-on quickly, i.e. Spontaneous.
thorough clinical evaluation of the patient. Reassurance of (Seldom, something that has been present for several
the patient is the first step in management of an Endodontic months).
324 Short Textbook of Endodontics
• A true Endodontic emergency awakens the patient from – Subjective examination: Careful questioning is
sleep. the most important aspect of diagnosis in case of
The patient can be disoriented from lack of sleep or Endodontic emergencies. Questions relate to onset
ingestion of analgesics. of pain, location, intensity, duration, character,
• Pain of odontogenic origin is usually acute in onset and aggravating and relieving factors, etc. Careful
severe. questioning usually provides important information
Irreversible inflammation of pulp or infection of pulp about the source of pain, whether it is pulpal or
that has affected the periapical area periradicular (Pain elicited by thermal stimuli or pain
↓ that is referred indicates pulp is the likely source of
Acute periapical periodontitis or abscess pain; pain that occurs on tooth contact or while biting
↓ and is well-localized indicates periapical pathology).
Acute pain Subjective examination helps to arrive at a tentative
• When inflammation spreads to the periodontal ligament diagnosis, objective examination and radiographic
and surrounding osseous structures findings are used for confirmation.
↓ – Objective examination: It includes careful extraoral
Pain intensifies and localizes. and intraoral examination of oral soft and hard
Due to higher innervations of proprioceptors in the PDL, tissues. Note the presence of deep carious lesion in
pain is easier to localize. the tooth, any related swelling, defective restorations,
Often, potent analgesics are not adequate to control fractures, etc.
Endodontic pain which can awaken the person from sleep. - Pulp vitality tests: Thermal tests for reaction to
Odontogenic pain is eliminated with Endodontic treatment heat and cold and electric pulp test indicate
(root canal treatment) or tooth extraction. the pulp status. To identify the offending tooth,
repeat the tests with the stimulus that patient
HOW TO MAKE CORRECT DIAGNOSIS IN reports subjectively. For example, cold test will
CASE OF ENDODONTIC EMERGENCIES? reproduce the pain of same type and magnitude
• Differentiation of ‘emergency’ and ‘urgency’: A true as related by the patient.
‘Emergency’ is a condition that requires an unscheduled - Periradicular tests include palpation over the
visit with diagnosis and treatment. The visit cannot apex, digital pressure or light percussion of the
be rescheduled due to severity of the problem. A true teeth with butt end of mirror handle and selective
emergency disrupts patient’s activities, sleep or quality biting on an object such as cotton swab or tooth
of life and has rarely been severe for more than few hours slooth. Percussion is an important test as it
to 1–2 days. Analgesics usually do not relieve the pain determines whether inflammation has extended
of true emergency. A rule of true emergency is that one to the periapical tissues.
tooth is the offender, which is the source of pain. - Periodontal examination: Probing helps to
‘Urgency’ indicates a less severe problem. So the visit differentiate Endodontic from periodontal disease.
can be scheduled as per the convenience of the patient A periodontal abscess can simulate acute apical
and the dentist. abscess. But the important differentiating point
• System of diagnosis: In the presence of severe pain, is that the pulp is usually vital in case of localized
patient may provide information and responses that are periodontal abscess whereas acute apical abscess
exaggerated and inaccurate. Such patients tend to be is related to an unresponsive (necrotic) pulp.
apprehensive and may be confused. Before any treatment – Radiographic examination: Although, radiographs
is given, it is important to make correct diagnosis in are quite useful in deciding on correct emergency
order to avoid giving wrong treatment which will further treatment when minimal time is available to gain
complicate the problem. So a systematic approach should pain relief, but the tendency to rely too much on
be followed which includes obtaining medical and dental radiographs may lead to unfortunate consequences.
history and careful clinical and radiographic examination Intraoral periapical radiographs and bitewing
and use of other diagnostic aids. radiographs may detect presence of interproximal
– Medical history: Presence of any medical problem and recurrent caries, pulpal exposure, presence
and any medications that the patient is taking should or absence of periapical lesion, thickening of
be recorded. periodontal ligament, etc.
– Dental history: Patient’s last dental visit or any recent
dental treatment should be recorded.
Endodontic Emergencies and Midtreatment Flare-ups 325
Pretreatment
Intratreatment
• Apical periodontitis secondary to treatment
• Incomplete removal of pulp tissue
• Recrudescence of chronic apical periodontitis
• Recurrent periapical abscess.
Grossman’s Classification of Endodontic • There may be pain in the tooth on change of position of
Emergencies head.
• Acute reversible pulpitis • Involved tooth may have extensive restoration or deep
• Acute irreversible pulpitis caries.
• Acute alveolar abscess
• Emergencies during treatment related to trauma caused Causes
to periapical tissues due to over-instrumentation, • Presence of mediators of inflammation that lower the
extrusion of irrigants or chemicals beyond apex, over- threshold of stimulation of intrapulpal nerve fibers
filling. • Dental pulp develops allodynia and hyperalgesia
• Traumatic injury causing crown fracture, root fracture, • Thermal stimulation of A-delta nerve fibers causes
avulsion. lingering pain, stimulation of unmyelinated C-fibers
causes spontaneous, dull aching pain
ENDODONTIC EMERGENCIES IN DETAIL • Inflammatory process has progressed and has resulted
in irreversible pulpitis.
We will discuss the Endodontic emergencies under the
following categories: Diagnosis
• Pretreatment Endodontic emergencies: Made by visual and tactile inspection, diagnostic tests:
– Related to pathosis of pulp and periradicular tissues thermal, electric pulp tests, radiographic examination.
- Acute irreversible pulpitis The findings that pain coming from a vital pulp in a
- Acute pulpitis with acute apical periodontitis tooth without tenderness to percussion establishes that
- Gangrenous necrosis of pulp inflammation has not involved the periapical tissues.
- Acute alveolar abscess Radiographically, there is no change from normal in the
– Related to traumatic injuries: periapical tissues. However, radiograph may show some
- Crown or root fracture cause of pulp inflammation such as deep caries, extensive
- Tooth avulsion restoration, etc.
• Interappointment emergencies:
– Hyperocclusion Management
– Pain related to incomplete removal of pulp • A tooth with irreversible pulpitis presents as a true
– Recrudescence of a chronic apical periodontitis emergency and emergency root canal opening
– Midtreatment flare-ups (ERCO) needs to be carried out to alleviate patient’s
– Irrigant-related mishaps—Sodium hypochlorite pain. Complete removal of pulp and total cleaning
accidents and shaping of the root canal system is the treatment
– Tissue emphysema of choice for emergency irreversible pulpitis, if time
• Postobturation emergencies: permits.
– Overinstrumentation and overfilling But if there are time constraints, then pulpotomy
– Hyperocclusion/high restoration (total pulp tissue removal) from pulp chamber and
– Crown or root fracture partial pulpectomy from at least the largest root canal
– Underfilling. in case of molars (palatal or distal), should be done. This
can also provide pain relief. Root canal treatment can be
ENDODONTIC EMERGENCIES BEFORE completed in the next appointment.
TREATMENT • Relieving occlusion is not indicated in these cases
without periapical involvement.
Related to Pathosis of Pulp and • Since the irreversibly infamed pulp is still vital and
Periradicular Tissues immunocompetent, with the ability to resist bacterial
infection, antibiotics are not indicated in these cases.
Acute Irreversible Pulpitis
Signs and Symptoms Irreversible Pulpitis with Acute Apical Periodontitis
• Patient presents with spontaneous pain and exaggerated
response to hot or cold that lingers even after the Signs and Symptoms
stimulus is removed. • Discomfort to biting or chewing
• Severe pain that may even affect sleep. • Tooth is tender to percussion
Endodontic Emergencies and Midtreatment Flare-ups 327
• Both pulpal and periapical symptoms as the pulpal • In between visits, the canals can be medicated with
inflammation has spread to periradicular tissues calcium hydroxide to prevent bacterial regrowth.
• Pain is increased by heat (hot stimulus) and relieved by • Relieving occlusion reduces postoperative pain in teeth
cold (cold stimulus). In few cases, patient may arrive that exhibited pulp vitality, sensitivity to percussion and
in the clinic applying ice to the affected area or sipping preoperative pain.
a glass of ice water, saying that cold reduces pain and • Antibiotics are not needed. Analgesics may be prescribed
removal of cold causes return of symptoms. to be taken as and when required to relieve pain.
• In few cases, there may be sensitivity to both heat and
cold. Gangrenous Necrosis of the Pulp
Causes
Pulp necrosis is partial or total death of pulp following
• Inflammation of PDL due to:
inflammation or a traumatic injury in which pulp gets
– Extension of pulpal pathosis
destroyed before an inflammatory reaction takes place. As a
– Occlusal trauma
result, an ischemic infarction can develop which may cause
– Tissue damage
a dry-gangenous necrotic pulp.
• Pressure on the tooth gets transmitted to the fluid which
pushes on nerve endings of PDL resulting in pain
Causes
• Pressure build up in the PDL may cause elevation of
• Untreated symptomatic or asymptomatic irreversible
tooth out of its socket so the pain occurs when tooth
pulpitis progresses to necrosis.
comes in contact with the opposing tooth.
• Trauma.
Diagnosis Basically, injury to pulp by noxious stimuli such as
Pain on percussion is an important diagnostic test. bacterial, traumatic or chemical irritation can lead to
Inspection, radiographic examination and other diagnostic necrosis of pulp.
tests such as thermal or electric pulp vitality tests confirm
Types
the diagnosis.
Widening of PDL space may be seen on radiograph.
Management
• Complete extirpation of pulp and thorough cleaning
and shaping of root canals is preferred, if sufficient time
permits. In nonmolar teeth, this is usually possible. But
in case of molar teeth, if time does not permit complete
pulpectomy, then partial pulpectomy from the largest
canal is done.
• Achieving adequate anesthesia is sometimes a problem
in case of acute pulpitis with acute apical periodontitis
due to severe inflammation. More dosage of anesthetic
may be needed. In cases of severely inflamed pulp,
patient may still feel the sensitivity to access preparation,
even after good signs of paresthesia have been obtained.
Patient needs to be reassured and explained that severe
inflammation is preventing the anesthetic to attain full
effectiveness and requested to endure the discomfort Diagnosis
for few more minutes until the anesthetic can be directly • In some patients, there can be slow death of pulp
administered into the inflamed pulp tissue (Intrapulpal without any symptoms. Pulp necrosis rarely causes a
anesthesia under pressure), after which usually no true emergency.
further pain will be experienced. • In few cases, there may be a history of severe pain lasting
• In acute pulpitis with acute apical periodontitis, since from few minutes to few hours, followed by cessation of
the inflamed tissue is present in the apical portion of the pain completely.
root canal, performing only pulpotomy will not provide • Tooth is not sensitive to percussion or may become
relief of pain. mildly sensitive as the infection extends into PDL space.
328 Short Textbook of Endodontics
• Then carry out debridement and cleaning and completion of apexogenesis. At the intervals of 3 to 6
shaping of the root canals after correct working length months, radiographs are taken to evaluate the degree
determination to confine the instruments in the root of apical development.
canal. – In case if the pulp is found to be nonvital and
• Antibiotics may be prescribed if indicated. Usually if the apical closure has not occurred, then apexification
patient is febrile and minimal drainage has occurred, procedure needs to be done after cessation of acute
an antibiotic should be prescribed. But when sufficient symptoms.
drainage has been established and patient is afebrile, • Root fracture: May present as an Endodontic emergency.
no antibiotic coverage is needed. Classification
• Analgesics may be taken as and when required.
• The tooth should be slightly disoccluded if it is extruded
from its socket.
Fig. 19.1 Radiograph showing horizontal fracture in Endodontically Fig. 19.2 Radiograph showing vertical crown-root fracture involving
treated maxillary right central incisor (Courtesy of Dr Samir Khaire) enamel, dentin and pulp and extending to the root (Courtesy of Dr
Chetan Shah)
Endodontic Emergencies and Midtreatment Flare-ups 331
Hyperocclusion
Signs and Symptoms
If the temporary filling that was placed after the first visit is
high, i.e. in hyperocclusion, patient will continue to feel the There can be moderate to severe pain with or without
discomfort and pain till it is relieved. swelling that occurs soon after the effect of anesthesia wears
As the patient reports to the clinic and hyperocclusion off following patient’s dental appointment or later.
is found to be the cause of pain, the occlusion should be
adjusted. In cases with periapical lesion, further relief Causes
of occlusion to keep the tooth out of contact has been Patient-related factors or operator-related factors: Generally
advocated to eliminate any intra-appointment pain. the cause is any kind of mechanical, chemical and/or
In the next visit, the root canal treatment procedure can microbial injury to the pulp or periapical tissues that is
be completed. If working length had been determined prior induced or gets exacerbated during Endodontic treatment.
to relief of occlusion it should be taken again due to change Microbial induced injury is the major cause of
that occurs as a result of reduction of reference points, i.e. Endodontic flare-up.
occlusal cusps. • Patient-related factors:
– Fear and anxiety: High levels of fear and anxiety
Pain Related to Incomplete Removal of Pulp Tissue concerning the Endodontic procedure causes
the patient to perceive the slightest pressure and
If during the initial appointment for Endodontic therapy, discomfort as ‘pain’.
pulpotomy or partial pulpectomy was performed, the – Tooth type: More common in mandibular teeth than
patient may experience pain due to incomplete removal maxillary teeth. Mandibular premolars followed by
of inflamed pulp tissue. Anesthesia is administered and mandibular incisors have been found to have highest
thorough cleaning and shaping of root canals is done. incidence of flare-ups after cleaning and shaping.
– Age, gender, history of allergy: It has been found that
Recrudescence of a Chronic Apical Periodontitis flare-ups occur commonly in women more than 40
years and in patients with history of allergies.
(Phoenix Abscess)
– Vital v/s necrotic pulp: Necrotic teeth show greater
Most teeth with necrotic pulps and apical lesions which are incidence of flare-ups than the vital teeth.
asymptomatic, referred to as chronic apical periodontitis, – Teeth with preoperative apical periodontitis are
may become acute after the first Endodontic appointment. associated with increased incidence of midtreatment
This condition is called as recrudescence or acute flare up.
exacerbation of chronic abscess or a phoenix (rebirth) – History of preoperative pain: These are associated
abscess. with increased incidence of flare-ups.
This may occur due to change in the environment – Retreatment cases: These are usually associated with
within the root canal. Multiple strains that were harboured a persistent or secondary root canal infection caused
in a particular lesion, few strains may be severely reduced by therapy-resistant microorganisms that may be
and few strains may be relatively unaffected. Due to fewer more difficult to eradicate in comparison to primary
organisms with which to compete, a virulent strain may then Endodontic infections.
begin rapid multiplication. Retreatment cases have shown significantly higher
The symptoms of Recrudescence are similar to acute incidence of flare-ups than conventional cases.
periapical abscess: mobility, tenderness to percussion and – Decrease in host-resistance or increased microbial
swelling. Same emergency management as for acute abscess virulence may allow a previously asymptomatic
needs to be done. tooth to become symptomatic.
postoperative pain and inflammatory response - There is change in the environment of the
due to forcing of infected debris into the periapical root canal due to the Endodontic procedures
tissues. that favors the growth of some pathogens in
– Incomplete debridement: incompletely instrumented canals predisposing
- If only pulpotomy or partial pulpectomy has to flare-ups.
been performed, patient may experience pain - Due to bacterial interaction and changes in
in between appointments due to remaining oxidation-reduction potential, microorganisms
inflamed pulp tissue. tend to become more virulent and induce higher
- It has also been found that due to incomplete concentrations of inflammatory molecules and
instrumentation, there is imbalance within cytokines from damaged periapical tissues
the microbial flora that may allow previously causing flare-up. It is found that asymptomatic
inhibited virulent species to overgrow resulting in infected teeth with periapical pathosis or
exacerbation of the lesion. Also, environmental asymptomatic retreatment cases, suddenly
changes that are induced by incomplete develop a flare-up after initiation or continuation
debridement also have the potential to activate of root canal treatment.
the virulence genes. - Preoperative symptomatic teeth already have
– Overfilling and overextension: pathogens associated with pain or acute
- Overextension of sealer (and its cytotoxic periapical abscess in the root canals. Such
components), and/or gutta-percha into the cases are predisposed to flare-ups if incomplete
periapical area can cause tissue damage and debridement is done or if there is extrusion of
inflammation that can result in increased the infected debris into the periapical area.
pain and percussion sensitivity especially Thus,
immediately after obturation and may last for
few more days.
– Acute apical periodontitis:
- When obturation is done in a tooth with
significant acute apical periodontitis, there is
more possibility of increased postoperative
pain. So, it is advisable to postpone obturation to
next visit in cases that present with acute apical
periodontitis till the tooth becomes comfortable.
– Microbiologically based (such as in infected necrotic • Look for the adjacent or opposing teeth other than
cases.) the tooth undergoing Endodontic treatment for
• In case of swelling, drainage needs to be established: any pulpal or periapical pathology causing pain and
Drainage can be achieved by soft tissue incision and re- swelling.
opening the access cavity that may allow purulent and • Rule out nonodontogenic causes of pain in the area
hemorrhagic exudates to be discharged and reduce the of tooth undergoing Endodontic treatment by paying
periapical pressure to cause relief of pain. attention to the vague symptoms felt by the patient.
Along with establishing drainage, the canals can be • Review the treatment performed in the previous
accessed, instrumented and thoroughly irrigated and appointment and try to find out the exact cause of
then give dressing (seal with temporary filling). Endodontic flare-up.
Prescribe antibiotics and anti-inflammatory drugs.
• In case of pain without any associated swelling, Prevention
– First establish profound local anesthesia.
– Reopen the access cavity. Endodontic flare-ups can be prevented by:
– Check for any canals that were missed in previous • Elimination of patient’s anxiety and fear concerning
appointment that contain inflammatory pulp tissue Endodontic procedures by adopting various anxiety
and treat it. reduction measures discussed in Chapter 17: Drugs or
– Reconfirm the established working lengths of the Medicaments used in Endodontic Treatment.
canals. • Careful and appropriate treatment:
– Achieve patency to the apical foramen. – Accurate determination of working length
– Perform thorough debridement with copious – Avoid inadvertent overinstrumentation
irrigation and complete the canal cleaning and – Once you start instrumentation, complete
shaping procedures. the cleaning and shaping of the canals in that
In case of excruciating pain in the tooth with no appointment itself in order to avoid inflamed pulp
associated swelling, where drainage cannot be achieved, tissue to remain in the canals.
surgical perforation of the alveolar cortical plate over the • Relieve occlusion: Especially in cases with acute
apex of the root called as ‘Trephination’, may be performed apical periodontitis present preoperatively. Relieving
to release the exudates that is causing pain. occlusion is found to be a predictable method to prevent
• In case of history of acute apical periodontitis: A tooth with postoperative pain and relief of pain due to acute apical
history of acute apical periodontitis, in which occlusal periodontitis.
reduction was not done, that could be the probable • Anti-inflammatory and analgesic drugs: Such as NSAIDs
cause of postoperative pain. Occlusal reduction should and acetaminophen given preoperatively have been
be done in such cases to relieve the pain that reduces found to be effective to reduce postoperative pain.
the mechanical stimulation of sensitized nociceptors In cases where there is predictable possibility of flare-
relieving the pain. up, patient can be asked to take these drugs immediately
• If flare-up resulted due to overinstrumentation: Relief of after treatment before the effect of local anesthetic
pain is achieved by giving analgesics. wears off rather than taking medications after the onset
In case of flare-up related to underinstrumentation: of pain.
Further instrumentation to the correctly measured • Use of long-acting local anesthetics: Can provide
length as well as analgesics can provide pain relief. analgesia for prolonged period beyond the usual
• Intracanal medicament: Use of intracanal medicaments duration of anesthesia.
such as calcium hydroxide between visits can reduce the Thus they are valuable in providing analgesia during the
bacterial count. immediate postoperative period.
A mind map to remember midtreatment flare-ups is
Diagnosis given is Figure 19.3.
This involves finding the cause of pain and associated Irrigant-related Mishaps
swelling if present.
• Any associated periodontal etiology that was left Sodium hypochlorite accidents can present as Endodontic
undiagnosed in the previous visit, should be looked for. emergency. It has been discussed in the next chapter.
334 Short Textbook of Endodontics
Tissue emphysema is the collection of gas or air in the body • Air may get entrapped in tissues during periapical
tissues or spaces. surgery if air from air rotor is directed towards the
exposed soft tissues.
Signs and Symptoms • If blast of air through three-way syringe of dental chair
is directed towards open root canals to dry them.
• Rapid swelling that develops in seconds or minutes • As a result of complication of fracture involving facial
• Erythema or redness skeleton.
• “Crepitus” or cracking sound on palpation of affected
tissues, is the pathognomonic sign of tissue emphysema. Differential Diagnosis
• Migration of air into neck region can cause respiratory • Anaphylaxis
difficulty and its progression to the mediastinum can be • Internal hemorrhage
fatal. • Angioedema
Endodontic Emergencies and Midtreatment Flare-ups 335
20
CHAPTER
Management and
Prevention
This chapter discusses in detail the various aspects of Endodontic mishaps to guide the clinician to be
careful in performing all Endodontic procedures for a safe and prudent Endodontic practice.
You must know
• What are Endodontic Mishaps?
• How do we Classify Endodontic Mishaps?
• Endodontic Mishaps in Detail
Clinician may make an unreasonable mistake by making Errors and Mishaps Related to
access opening in a wrong tooth, often the tooth adjacent
Access Cavity Preparation
to the involved tooth. This may occur due to:
• Improper rubber dam placement Errors may occur in access cavity preparation if:
• Tooth recorded incorrectly on the referral slip • There is clinician’s lack of understanding of the internal
(Miscommunication of a referral). or external morphology of tooth, or
• Inaccurate or incomplete review of records, especially • The clinician does not follow the access guidelines.
radiographs.
• Radiographs mounted incorrectly Poor Access Cavity Design
• Lack of concentration.
To avoid such error, clinician must do complete review of • Inadequate extension: Inadequate mesial or distal
records and correlate clinically and be sure of the involved extension may leave the orifices uncovered.
tooth requiring treatment. If rubber dam has been placed Failure to remove the pulpal roof completely is called
by the dentist or staff, steps should be taken to minimize vertical underextension.
the risk of isolating the wrong tooth. • Inadequate opening: Inadequate access opening results
in inadequate instrumentation and obturation and it can
Improper Diagnosis Leading to also cause various procedural problems like:
Unnecessary Endodontic Treatment – Coronal discoloration when pulp horns are not
• Incorrect diagnosis due to wrong judgement may occur debrided
when clinician finds difficulty localizing the source of – Instrument breakage (separation)
Endodontic pain leading to unnecessary Endodontic – Ledging of canal as demonstrated in Figure 20.2.
treatment. – Apical transportation.
• Vital pulps may be sacrificed sometimes in an attempt • Overextension: Gross overextension of access cavity
to diagnose the source of pain. preparation will weaken the coronal tooth structure and
338 Short Textbook of Endodontics
hence compromise the final restoration and longevity tooth can result in overzealous tooth removal referred
of the treated tooth as demonstrated in Figures 20.3A to as gouging. This results in weakening and mutilation
and B. of tooth structure predisposing it to fractures.
• Overzealous tooth removal: Gouging—Improper bur
angulation and failure to recognize the inclination of Perforations
According to American Association of Endodontists,
“Perforation can be defined as the mechanical or
pathological communication between the root canal system
and the external tooth surface.”
Perforations result in communication between the
root canal system and the periodontal tissues, which can
significantly affect the long-term prognosis of a tooth.
Furcation perforation is considered to be the worst
possible outcome in root canal treatment. Figure 20.4 shows
diagrammatic representation of furcation perforation.
Etiology:
• Improper bur angulation
• Failure to recognize inclination of tooth
• Difficulty in accessibility to the tooth due to its location
• Failure to determine the distance between the occlusal
surface and furcation, can result in furcal perforation
• During search for canal orifices
A B
Figs 20.3A and B Overextension of access cavity preparation can Fig. 20.4 Iatrogenic procedural error: Perforation of the furcation
weaken the coronal tooth structure shown by arrows (A) that reduces during access cavity preparation
the longevity of Endodontically treated tooth and can cause fracture
of the tooth under occlusal forces (B)
Endodontic Mishaps: Management and Prevention 339
Types of perforations:
i. Subgingival perforations occur during the access cavity
preparation and the search for canal orifices.
ii. Midroot perforations occur mainly during postspace
preparation or during aggressive cleaning and shaping
the midroot area of the canal.
iii. Apical perforations occurs during instrumentation.
Using large inflexible file in curved canals violates the
apical constriction
achieved, repair with the appropriate material is carried • Pay careful attention to the three-dimensional spatial
out immediately. orientation of the tooth by means of:
If the perforation is long-standing, the site is first – Three clear preoperative radiographs: 2 IOPAs and
disinfected and may be prepared with ultrasonic instruments 1 bite wing
before receiving the appropriate restorative material. – Palpation and periodontal probing of root surfaces
to assess the long-axis of tooth root especially during
Step 3: Maintain the patency of canal: The barriers and the access preparation through prosthetic crowns.
restorative materials used can inadvertently cause canal • The access cavity preparation bur can be placed on
blockage during perforation repair procedure, so a paper a preoperative radiograph (IOPA) to estimate the
point or gutta-percha point or a collagen plug can be placed distance between occlusal surface and furcation and
in the canal apical to the defect to maintain the patency of the approximate depth of pulp chamber.
the canal. • Use safe, nonend cutting Endo access burs once
deroofing of pulp chamber has been accomplished.
Perforation repair: When esthetics is a concern, a calcium A mind-map to remember all points of perforations
sulfate barrier, in conjunction with composites, glass is given in Figure 20.6.
ionomers or white MTA can be used.
When esthetics is not an issue, super EBA, amalgam or Errors in Cleaning and Shaping
MTA can be used.
Incomplete Debridement
It should be understood that MTA is material of choice
for perforation repair only when there is no sulcular Inadequate cleaning and shaping can result in pulp tissue,
communication. debris and bacteria to remain in the root canal system
causing reinfection and thus Endodontic failure. Figure
Step 4: Completing the treatment: Wait for the perforation 20.7 shows diagrammatic representation of incomplete
repair material to set hard. MTA takes about 4–6 hours. debridement in apical third of the root canal.
The tooth can then be cleaned, shaped and obturated. • Etiology:
– Anatomic difficulties: Curvatures, calcifications.
Factors Affecting Prognosis for Healing of Perforation – Errors in working length determination or failure
to follow the exact working length (Loss of working
• Location of perforation in relation to gingival sulcus: If length during instrumentation) due to improper
the perforation site is located near gingival sulcus, there instrument stops, variation in reference points,
is potential for periodontal inflammation and loss of carelessness, etc.
epithelial attachment causing pocket formation, thus – Missed canals: Failure to locate canals and carry out
affecting the prognosis. their cleaning and shaping will result in pulp tissue
Perforation located away from gingival sulcus and and microorganisms to remain in these canals.
healthy periodontium has fair prognosis for healing. – Inadequate irrigation.
• Size of perforation: Smaller defect has better prognosis – Due to procedural errors such as ledges and
due to ease of attaining proper marginal adaptation, blockages that prevent complete cleaning and
and well-condensed uncontaminated seal and smaller shaping.
contact surface area of restorative material with • Prevention
periodontium. – Pay careful attention to the anatomy of the root canal
• Time elapsed between inception of perforation and seal: system. Take appropriate steps to safely clean and
Immediate repair provides favorable prognosis than shape curved canals.
delayed repair as further loss of attachment and pocket – Combination of methods to determine the correct
formation is prevented. working length. Use of apex locators along with
• Perforation repair material used. radiographs and use of paper points to determine
• Clinician’s skills. the working length.
Confine and use all instruments to the correct
Prevention of Perforation working length by using proper instrument stops and
sound reproducible reference points. Directional
• Understand the external and internal morphology of instrument stops should be used and direction of
tooth. stop must be constantly observed.
Endodontic Mishaps: Management and Prevention 341
Fig. 20.7 Incomplete debridement of canal. Apical 1/3rd of canal Fig. 20.8 Overinstrumentation of canal. Overinstrumentation can
left uninstrumented leading to persistence of microorganisms and cause trauma to periapical tissue, transport of bacteria and debris
debris in RC system into periapical area, lack of adequate apical seal, risk of overfilling
and postendodontic infection
Fig. 20.9 Separated instrument in the apical Fig. 20.10 Radiograph of Endodontically treated mandibular
third of root canal second molar with a separated instrument in the mesial canal
- Dentin shavings and debris incorporated in the – The surgical operating microscope increases
flutes of instrument causes greater frictional visibility by the use of magnification and light
forces and results in separation. and is a necessary tool for retrieval of separated
– Overuse: When the instrument has been excessively instruments.
used resulting in bending or crimping, use of such – Separated instrument removal techniques vary
an instrument in the canal leads to its separation. according to the location of the instrument in the
Such bending may not be evident on nickel- canal.
titanium instruments and they may break without - Removal techniques for separated instrument in
any warning. Cutting efficiency of Ni-Ti instruments coronal portions of canal:
is reduced by 50% after initial use. Risk of breakage ■ If the instrument is clinically visible in the
of Ni-Ti hand and rotary files increases if they are coronal access and is loosely fitting in the
re-used. canal and can be grasped with an instrument,
– Manufacturing defect: Defective instrument tips are a hemostat or Stieglitz pliers can be used to
more likely to separate during use. hold the instrument and extract it out through
– Anatomy of tooth: Abrupt curvatures or anatomic access cavity preparation. Sometimes, a slight
ledges, prevents free passage of instrument in the counter clockwise action will be required to
canal. Clinician may tend to force it and this may unscrew the flutes.
result in file separation. - Removal techniques for separated instrument in
Figure 20.10 shows the radiograph of Endodontically deeper portions of canal:
treated mandibular second molar with a separated ■ If the instrument is not clinically visible but
instrument in the mesial canal. appears to be in coronal portions of the canal
• Management: on radiograph, first step is to flare the canal
– If instrument separation occurs, first take a wall along side the instrument to provide
radiograph to confirm separation and to find its space for subsequent treatment. This can
location, size of broken fragment, and whether be done by using hand files, small to large,
removal is possible or not. coronal to obstruction or with Gates Glidden
– Inform the patient about the accident and preserve drills used in a ‘brushing action’ to create
the remaining segment of instrument in a coin a uniform tapered shape and maximize
envelope in the patient’s record for medicolegal visibility. GG1 and GG2 can be used to the
purpose. depth of head of the separated instrument in
344 Short Textbook of Endodontics
the straight portions of the canal. At this stage, and then use an extraction device to retrieve
if the separated instrument becomes loose in it.
the canal, it can be held with a hemostat and ■ Some of the available extraction devices and
extracted. kits for separated instrument removal are:
■ If the instrument is tightly binding in the the Endo Extractor, the Masserann kit and
deeper portion of the canal achieve straight- the Extractor system.
line coronal radicular access with GG drills – If the separated instrument lies apical to the canal
to create a circumferential staging platform curvature and orthograde removal is not possible
to facilitate ultrasonic use. and there is persistent disease and separated
When an ultrasonic tip is placed on the instrument cannot be bypassed safely, then apical
staging platform between the exposed end surgery or extraction may be necessary.
of the file and the canal wall and is vibrated – If the separation occurred during later stages of
around the obstruction, the separated preparation and the preoperative pulp was vital and
instrument is unscrewed and loosened and noninfected, bypass the instrument and incorporate
jumps out of the canal. it into obturation.
■ But if the separated instrument cannot Also, if removal of separated instrument requires
be loosened with ultrasonic energy, the excessive enlargement of canal or has the risk for an
separated fragment can be grabbed and additional iatrogenic mishap such as perforation, then do
retrieved using various techniques and not attempt removal, incorporate it into obturation. Observe
devices such as a microtube system or use of the case closely and if symptoms persist, consider apical
an end-cutting trephine bur to remove tooth surgery or extraction. Figure 20.11 gives the factors affecting
structure around the separated instrument removal of separated instrument.
A B
Figs 20.13A and B Iatrogenic procedural error: Canal blockage
leading to improper cleaning and shaping of root canal due to: (A)
Dentinal mud; (B) Separated instrument
– Insertion of instruments short of working length Fig. 20.14 Ledge formation in root canal
– Use of straight or inflexible instrument in a curved
root canal
– Poorly designed access cavity that prevents straight
line access to apical third of root canal. – Determine correct working length and use
• Recognition of ledge: instruments till that length
– Instrument does not reach the estimated working – Precurve the instruments for use in curved canals
length – Adequate access cavity preparation and straight line
– On tactile sensation, the instrument does not bind access to the apical third of the canals.
at the apex but feels loose.
• Management: Ledge typically occurs on the outer wall Missed Canals
of the canal curvature.
– Choose the shortest file to reach working length • If the clinician fails to detect a canal, it may be left
lubricated with EDTA and gently slide the file to untreated and can act as reservoir of tissue debris,
length. bacteria and other irritants and subsequently result in
– If above is not possible, pre-enlarge the canal above Endodontic failure.
the stopping point to facilitate moving it to length. • Common sites of missed canals: Several teeth with
– If obstruction is encountered, use precurved file in predisposition for extra canal, which might be missed,
an apically directed, gentle pecking motion. such as:
– Use small-sized instrument lubricated with EDTA – Maxillary premolars may have three canals
with very short amplitude, light pecking strokes in – Maxillary first molars usually have four canals
order to negotiate the canal terminus. – Mandibular incisors usually have extra canal
– When the instrument tip is apical to a ledge, it is – Mandibular premolars often have complex root
moved in short push-pull motion to reduce the anatomy
ledge and to confirm the presence or absence of any – Mandibular molars may have extra mesial and/or
residual internal canal irregularities. distal canal.
– After the ledge is bypassed, establish patency of the • Clinician must use all possible armamentarium to locate
canal with a #10 K-file. Enlarge up to #20 K-file and and treat the entire root canal system.
then Ni-Ti instruments can be used to complete the Diagnostic aids for location of root canal orifices include:
root canal preparation. – Careful examination of multiple pretreatment
• Prevention: radiographs taken at different angles
– Be careful in instrumentation – Use of sharp explorer, DG 16 Endodontic explorer to
– Use instruments in correct sequence examine the pulp chamber floor
348 Short Textbook of Endodontics
– Use of ultrasonic tips to detect and explore the iii. Adequate access cavity preparation
troughing grooves iv. Sound knowledge about the possible anatomic
– Staining the pulp chamber floor with 1% methylene variations in the root canal system
blue dye v. Clinician must always look for an additional canal in
– Visualize the canal bleeding points every tooth being treated.
– “Champagne bubble” test: When sodium hypochlorite
is allowed to remain in the pulp chamber tiny Apical Transportation and Zipping
bubbles appear in the solution, indicating the
position of orifice. This test is especially useful in “Apical canal transportation is moving the position of the
locating calcified root canal orifice (Fig. 13.32). canal’s physiologic terminus to a new iatrogenic location
– If 17% EDTA and 95% ethanol is used sequentially, on the external root surface”.
it facilitates effective cleaning and drying of pulp Internal transportation of canal is called ledge.
chamber floor for enhanced visual examination. “Apical zipping or tearing is transposition of canal in the
– Use of magnification aids such as dental operating apical portion of the canal caused by using progressively
microscope, magnifying loupes improves the larger and stiffer files to working length”. Commonly seen in
clinician’s ability to locate and negotiate canals. curved canals. It is shown in Figure 20.15. Here instrument
The possibility of location of MB2 canal in remains within the confines of the root canal, but results in
maxillary 1st molar has been found to be: 40% with internal transportation of the canal.
naked eye, 60–70% with magnifying loupes, 80–90% Due to apical transportation, there is reversed apical
with dental operating microscope shape referred to as elbow preparation, which cannot
– Distinguishing the color difference of the dentin of provide the resistance form to condense gutta-percha
the pulp chamber floor and walls. resulting in vertically overextended but internally underfilled
– Adequately flared access cavity with diverging walls obturation as shown in Figure 20.16. Here instrument goes
increases the visibility for easy location of the root outside the confines of the root canal and results in external
canal orifices. transportation of the canal.
The potential for canal transportation is determined by
Prevention: cutting ability of file and rigidity of file.
i. Good radiographs with proper angulation It is important to understand that canal transportation
ii. Good illumination and magnification cannot occur as long as the file is engaged 360 degrees.
Fig. 20.15 Internal transportation of canal: Fig. 20.16 External transportation: a—Elbow; b—Apical zipping
a—Elbow; b—Apical zipping
Endodontic Mishaps: Management and Prevention 349
A file which is overused begins to cut on one side resulting • Filing the lateral wall of the canals with lateral pressure
in transportation. results in elliptication.
• Cause of elliptication: When less flexible curved
instrument is used in a curved canal it may overcut the
outer surface of curved canal and produces elliptic shape
of apical preparation.
• Elliptical preparation is difficult to obturate.
Apical Perforations
Use of large inflexible files in curved canals can violate the
apical constriction breaking the apical seal referred to as
apical perforation as shown in Figures 20.17 and 20.18.
• Management
– In case of type I canal transportation, attempt should
be made to create a positive apical canal architecture
if sufficient residual dentin can be maintained and
the preparation above the foramen can be corrected
without root weakening or lateral strip perforation.
– In case of type II canal transportation, an attempt
to create a positive apical canal architecture would
increase the risk of root weakening and perforation.
So, the management technique for type II apical
canal transportation is with the use of MTA, Fig. 20.17 Apical perforation
which creates a barrier from the periapical space.
It also helps to control bleeding and provides a
matrix against which the obturation can be safely
condensed without the risk of overextension.
The MTA is the material of choice in these cases
as it induces cementogenesis and is not affected by
presence of slight moisture. It sets hard within 4–6
hours with slight expansion.
– In case of type III apical canal transportation, barrier
technique is not feasible. Corrective apical surgery is
indicated. If it cannot be treated surgically, extraction
is the only alternative.
• Prevention:
– Precurve the files in case of curved canals.
– Avoid using larger and stiffer files to working length
especially in fine curved canals
– Use flexible files.
Elliptication
• Elliptication means cone-shaped preparation with the
middle third of the canal forming the apex or “elbow” Fig. 20.18 Failure to precurve the apical end of instrument in a
and the cementum surface forming the base of the cone curved canal and excessive apical pressure during instrumentation
known as the “zip” caused perforation in the apical portion of the canal
350 Short Textbook of Endodontics
Fig. 20.19 Side-vented irrigating needle that is fitting loose in root Fig. 20.20 Sterile gauze sponge held around the tooth to be
canal, not binding, is used to deliver the irrigating solution passively irrigated to prevent spilling of excess solution in mouth
352 Short Textbook of Endodontics
BIBLIOGRAPHY
1. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis:
Mosby; 2006.pp.944-1005, 24-32.
2. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics, 6th edn.
BC Decker Inc, Hamilton; 2008.pp.1088-147.
Restoration of
21
CHAPTER
Endodontically
Treated Teeth
This chapter discusses in detail the various principles involved in the restoration of an Endodontically
treated tooth and describes the restorative materials and clinical procedures for the same.
You must know
• How are Endodontically Treated Teeth Different?
• What is Expected out of Postobturation Restoration?
• What is Direct ‘Coronal-radicular’ Postobturation Restoration?
• What are the Factors to be Considered for a Postendodontic Restoration?
• What are the Ideal Requirements of a Restorative Material to be used for Postendodontic
Restoration?
• What are the Restorative Options for a Postendodontic Restoration?
• What is Post and Core Restoration?
• What is “Ferrule Effect” and “Biologic Width”?
• What are the Indications for Using Posts?
• What are the Required Clinical Characteristics of Posts?
• What are the Different Types of Posts?
• What are the Clinical Parameters for Post Selection?
• What are the Required Physical Characteristics of the Core?
• What are the Different Types of Core Materials?
• What is the Technique of Fabrication of Foundation Restoration?
• What are the Causes of Failure of Post and Core Restorations?
Fig. 21.1 Characteristics of Endodontically treated teeth Fig. 21.2 Effect of volume changes on Endodontically treated tooth
Volume Changes
Due to diminished volume, the Endodontically treated tooth
is weakened (Fig. 21.2).
• There is loss of tooth structure due to caries. Figure 21.3
is a radiograph showing considerable amount of carious
destruction of maxillary second molar tooth.
• Dental procedure causes further loss of tooth structure
– Removal of tooth structure in mesio-occlusodistal
(MOD) preparation may reduce the stiffness by 60%
due to loss of marginal ridge integrity
– Increased depth of cavity renders the cusps more
susceptible to flexure Fig. 21.3 Radiograph showing considerable amount of carious
– Increased width of occlusal isthmus causes further destruction of maxillary second molar (Courtesy of Dr Chetan Shah)
decrease in stiffness
– The structural integrity provided by coronal dentin is
destroyed due to Endodontic access to pulp chamber
causing greater flexion under function load.
Physical Changes
• There are changes in collagen cross-linking.
• There is loss of moisture causing dehydration of dentin.
• The commonly used root canal irrigants and disinfectants
such as sodium hypochlorite (NaOCl), ethylenediamine
tetra-acetic acid (EDTA) and calcium hydroxide interact Fig. 21.4 Effect of physical changes on Endodontically treated tooth
with root dentin.
NaOCl affects the organic substrate causing extensive
fragmentation of collagen (proteolytic action) and Esthetic Changes
EDTA affects the mineral content causing depletion of
calcium and also affect noncollagenous proteins (NCPs) • Pulpal hemorrhage due to trauma or pulp necrosis
resulting in erosion and softening of dentin. causes discoloration of a nonvital tooth.
• Due to altered physical properties of Endodontically • Biochemical alteration of dentin modifies the refraction
treated tooth, there is reduction in its strength and of light causing changed appearance of Endodontically
toughness (Fig. 21.4). treated teeth.
Restoration of Endodontically Treated Teeth 357
• This is the most important factor to be considered for • If the Endodontically treated tooth has to serve as
the choice of restoration. abutment for a fixed bridge, it will be subjected to greater
• Longevity of the tooth is affected when there is extensive transverse load than single crowns.
loss of sound tooth structure. • If the opposing dentition consists of removable partial
• Sound teeth with more than half the tooth structure denture, then the Endodontically treated tooth will be
intact, may be restored only with coronal restorations, subjected to comparatively lesser load.
without the need for posts. Such restorative considerations have to be kept
• When the amount of remaining tooth structure is less, in mind while choosing the optimal post-Endodontic
post and core and crown will have to be considered. restoration.
• In case of extensively damaged tooth structure,
additional procedure such as periodontal crown
lengthening procedure (CLP) or Orthodontic extrusion Esthetic Considerations
needs to be considered, to expose additional root Restoration for Endodontically treated teeth in the esthetic
structure to allow for a biologic restoration. zone of the mouth, require special considerations to restore
the natural appearance, such as:
Position of Tooth in the Arch and • Management of discolored anterior teeth by means of
the Subjected Occlusal Forces bleaching and other methods (discussed in Chapter 23
“Management of Discolored Teeth”).
Posterior teeth are constantly under ↓↓ • Careful selection of esthetic restorative materials such
compression load ↑↑ as tooth colored posts, cores, luting cement and crowns.
Anterior teeth are under shearing and →← • Careful handling of gingiva.
tensile force Shear
• Intact, nonvital anterior teeth can be restored with
WHAT ARE THE IDEAL REQUIREMENTS OF A
coronal restorations without the need for posts and/or
crowns.
RESTORATIVE MATERIAL TO BE USED FOR
• Nonvital anterior teeth that are extensively damaged POSTENDODONTIC RESTORATION?
require restoration with a crown, supported and retained
by post and core. The requirements of a restorative material to be used for
• Posterior teeth are always subjected to occlusal forces post-Endodontic restoration include:
and require cuspal protection against tooth fracture. • It should be biocompatible
• Post and core restoration should be done in posterior • It should provide a good seal of the coronal access cavity
teeth with extensive loss of coronal tooth structure, against leakage
followed by a crown. • It should be dimensionally stable
• Occlusal load increases with parafunctional habits • It should possess high compressive strength to provide
such as bruxism and such teeth with wear, cracks and protection against fracture
heavy function, need stronger restorative components • It should be tooth-colored (esthetic), especially if
to protect against fracture. it is to be used in anterior teeth with minimal loss
• If the position of anterior teeth in the arch is such that of coronal tooth structure that will not need a full
there is deep vertical overlap of maxillary anterior teeth coverage crown
to mandibular anterior teeth, then the maxillary anterior • It should have a contrasting color to tooth for better
teeth are subjected to: distinction in posterior teeth
– Horizontal protrusive forces • It should be easy to manipulate and should have short
– Lateral forces. setting time
When such teeth with heavy function lose extensive • It should have ability to bond to the tooth
amount of tooth structure, then stronger restorative • It should be nonstaining
components have to be used to resist flexion. • It should be radiopaque.
Restoration of Endodontically Treated Teeth 359
WHAT ARE THE RESTORATIVE OPTIONS FOR A Structurally Compromised Posterior Tooth
POSTENDODONTIC RESTORATION?
• Posterior tooth requires cuspal protection by means of
Structurally Sound Anterior Tooth onlay restoration, endocrown or a full coverage crown.
Endocrowns combine the post in the canal, the core and
• Anterior teeth need Endodontic treatment most of the the crown in one component. Onlays and Endocrowns
times due to trauma causing loss of vitality or sometimes allow for conservation of remaining tooth structure.
due to caries. Overlays incorporate cusps by covering the missing
• When there is minimal structural damage, restorative tissue.
treatment is limited to sealing the access cavity with • Onlays, overlays and endocrowns are fabricated in
Direct Composite restoration. laboratory from ceramics or hybrid resin composites.
• If discoloration is present, nonvital bleaching procedure Ceramics are a material of choice for indirect restorations.
is done, explained in detail in Chapter 23: Management • When significant amount of tooth structure is lost, post is
of Discolored Teeth. In case of untreatable discoloration needed to increase retention and stabilize and reinforce
with bleaching procedure or relapsing one, conservative the restoration. When the remaining tooth structure is
restorative treatment such as direct or indirect veneers adequate: Remaining walls of height of 3–4 mm from
is done. pulp chamber floor and thickness of 1.5–2 mm, then
post is not needed.
Nonvital Posterior Tooth with Minimal
Loss of Tooth Structure Simple Calculation to Determine Type of
Post-Endodontic Restoration
• Occlusal cavity or mesio-occlusal or disto-occlusal cavity
can be restored with either direct- or indirect-adhesive Anterior Teeth
intracoronal restoration. But the residual walls should
be thick enough (proximal ridges and buccolingual walls →
• Structurally intact + Access Restore the access
more than 1.5 mm thickness) tooth preparation opening with
• Depending on the functional and occlusal environment, composite resin
conservative restorative options should be considered. • Proximal cavity on + Access → Esthetically restore the
For example, in the presence of bruxism or steep one side (mesial or preparation proximal cavity and
occlusal anatomy, full coverage restoration (crown) is distal) seal the access opening
with composite resin
mandatory.
• Proximal cavity on + Access → Restore the proximal
both sides (Mesial preparation cavities and protect
Structurally Compromised Anterior Tooth and Distal) the tooth with a full
coverage crown
• Anterior tooth with significant loss of tooth structure Or
needs protection with a full coverage restoration Esthetic post and core
(crown), supported and retained by a core and possibly restoration followed by
post also. “Post and core” is explained in detail later in full coverage crown
this chapter. • Proximal cavity on + Labial + → Esthetic post and core
one or both sides Access restoration followed by
• When more than half of the coronal structure is lost
(Mesial/distal) and/or a full coverage crown
or when the remaining walls are extremely thin (less preparation
than 1 mm), a post is needed to increase retention and
stabilize and reinforce the foundation.
• Nonmetal esthetic posts such as ceramic or resin- Posterior Teeth
reinforced need to be done. Adhesion is the preferred Cuspal coverage is needed for all posterior teeth to prevent
mode of post cementation. fracture.
360 Short Textbook of Endodontics
• When all the axial walls of the → Coronal restoration 3. More than 2/3rds coronal structure lost, reduced wall
cavity are intact and have thickness followed by onlay height – Composite core + metal post or Amalgam core
greater than 1 mm restoration or full + metal post
coverage crown
Tooth preparation guidelines: Maintain all residual
• When there is one proximal cavity → Strong coronal restoration structures > 1 mm thickness (after core prep).
(Mesio-occlusal or Disto-occlusal) followed by full coverage
or two proximal cavities (MOD) but crown 4. More than ¾ coronal structure lost – Cast gold post and
the remaining three axial walls or core (+/- porcelain)
two axial walls are intact and have Tooth preparation guidelines: Maintain all residual
thickness greater than 1 mm structures > 1 mm thickness (after core prep) Internal
• When there are two proximal → Post and core restoration walls divergent.
cavities (MOD) and one labial/ followed by full coverage
lingual cavity and only one axial crown
wall remaining intact WHAT IS POST AND CORE RESTORATION?
• When both proximal axial walls → Post and core restoration
(Mesial and distal) and both labial followed by full coverage Post and core restoration is a foundation restoration that
and lingual axial walls have been crown supports the coronal restoration (full coverage crown) in an
destroyed and its a decoronated extensively damaged Endodontically treated tooth.
tooth with no axial walls remaining
Definition of ‘Post’ as given in Cohen’s
Pathways of Pulp (9th Edn.)
Clinical Protocols for Restoring Nonvital Teeth
“Post is a restorative dental material placed in the root of a
with Partial Restorations (Most likely Procedures)
structurally damaged tooth in which additional retention is
(Cohen’s Pathways of Pulp, 10th Edn.) needed for the core and coronal restoration”.
The post is either bonded or cemented into the root of
1. Minimal tissue loss—Composite restoration the tooth and part of the post extends coronally to anchor
2. Limited tissue loss in anterior tooth with minimal to the core.
moderate discoloration only—Veneer
Tooth preparation guideline: > 1 mm buccal reduction, Definition of ‘Core’ as given in Cohen’s
lingual enamel present.
Pathways of Pulp (9th Edn.)
3. Thin remaining walls—Overlay (Composite/Ceramics)
Tooth preparation guideline: Minimum 2 mm occlusal “Core is a restorative material placed in the coronal area of
reduction. the tooth that replaces carious, fractured or missing coronal
4. Loss of occlusal anatomy—Endocrown (Composite/ structure and retains the final restoration”.
Ceramics) The core is anchored to the tooth either by its extension
Tooth preparation guideline: Minimum 2 mm occlusal into the coronal aspect of the root canal or by means of an
reduction, extension into pulpal chamber. Endodontic post.
Post and core are fabricated of different materials. So,
Clinical Protocols for Restoring Nonvital Teeth the bond between the tooth, post and core is mechanical
retention by means of luting or bonding agents.
with Full Prosthetic Restorations (As given in
The post and the core, along with the luting or bonding
Cohen’s Pathways of Pulp, 10th Edn.) agents to retain them, together form the foundation
restoration.
1. Reduced walls but > ½ Crown height—Composite core The specific design of the foundation restoration varies
Tooth preparation guidelines: Maintain all residual with the relative clinical need for each of the individual
structures > 1 mm thickness (after core prep). components.
2. More than ½ coronal structure lost, reduced wall height The tooth, the post, the core, the bonding or luting
- Composite core + Ceramic post or Composite core + agents and the coronal restoration together form a monobloc
in vitro fiber post (unified whole). Appropriate selection of each of the
Tooth preparation guidelines: Maintain all residual components is essential for the clinical success of the fully
structures > 1 mm thickness (after core prep). restored tooth.
Restoration of Endodontically Treated Teeth 361
Basic Components of the Fully Restored Tooth Endodontically treated tooth against fracture by bringing
about proper transmission of forces.
The basic components of the fully restored tooth include: Figure 21.8 a shows the diagrammatic representation of
• Remaining coronal and radicular tooth structure ferrule.
(Fig. 21.7d). • The ferrule must:
• Restorative material in the root: post (Fig. 21.7c). – Be atleast 1.5–2 mm in height
• Restorative material in the pulp chamber and the – Have parallel axial walls
coronal area replacing the missing tooth structure: core – Completely encircle the tooth (360o)
(Fig. 21.7b). – End on sound tooth structure and not on the
• Restoration to protect the tooth and to restore the restoration
function and esthetics: Coronal restoration/crown – Not invade the attachment apparatus.
(Fig. 21.7a). • Functions of ferrule:
• Adhesive component to join each of the above – Dissipates the force that concentrates at the
components: Bonding or luting agents. narrowest circumference of tooth
The residual root and its attachment mechanism – Resists lateral forces from posts and leverage from
(supporting periodontium) must be preserved by Endodontic crown in function
therapy followed by appropriate restorative treatment. – Increases resistance and retention of the restoration
– Reduces the incidence of fracture in a nonvital tooth
WHAT IS “FERRULE EFFECT” AND by reinforcing the tooth at its external surface.
• Whenever there is loss of coronal tooth structure till the
“BIOLOGIC WIDTH”?
level of gingival margin and an effective ferrule cannot
Ferrule Effect be given, then there is chance of fracture of tooth or early
failure of restoration.
“The ferrule is a band of metal that encircles the tooth and In such cases, it is recommended to expose tooth
greatly increases its resistance to fracture”. surface by surgical crown lengthening procedure (CLP) or
Ferrule is a protective ring which encircles the tooth. by Orthodontic extrusion to prepare the ferrule.
Restoration encirclement of tooth with a ferrule will protect
Biologic Width
“The dimension of the junctional epithelial and connective
tissue attachment to the root above the alveolar crest is called
biologic width”.
Figure 21.8b shows the diagrammatic representation of
biologic width.
In order to preserve the biologic width, the margin of
the crown preparation should be about 2.5–3 mm away
from the alveolar crest.
Violation of biologic width during crown preparation
↓
Unexpected and uncontrolled bone loss around the tooth.
Figure 21.10 shows photograph of preformed metal posts Studies have shown that nonrigid posts tend to exhibit
along with their corresponding postspace preparation drills. fewer catastrophic irreversible root fracture.
• Advantages: Data indicates that nonrigid fiber posts are acceptable
– Rigid: Made of stiffer materials which do not fracture alternatives to metallic posts and can be used clinically
or bend easily wherever metal posts have been used.
– Radiopaque
– Dissipate functional forces along the length of root Advantages of Nonrigid Posts
and the periodontal structures. This is an important
consideration when there is minimal remaining • Designed to have physical properties similar to dentin
tooth structure for crown margins. Modulus of elasticity of dentin: 18 GPa
– Cervical stiffening is provided that protects the crown Modulus of elasticiy of fiberposts: 17–25 GPa.
margins and resists leakage. The primary benefit of lower modulus of elasticity is
• Disadvantages: protection of root from fracture (fiber posts prevent root
– Failure of metal posts can cause root fracture split) through reduction of transfer of forces through the
(Induces root split) post to the root.
– Stainless steel posts contain nickel, an allergen, that • Fiber-posts are resilient posts that flex with the tooth
can leach out through dentinal tubules into the tissue under function, thus reducing the transfer of force to
– Corrosion of stainless steel posts the root and reducing the risk of root fracture.
– Nonesthetic. • They are easily retrievable if Endodontic retreatment
has to be done.
Nonrigid Posts • Light transmitting posts and bonded composite provide
increased fracture resistance by reinforcing weakened
They are composed of glass, quartz or carbon fibers roots.
embedded in a resin matrix. • Fiber posts do not cause any stress concentration.
These are fiber-reinforced resin-based composite posts • Fiber posts are safer.
which are used with bonded resin-based composite core In case of failure of fiber posts, fracture of post occurs,
built-ups. which can be removed and replaced, rather than fracture
In modern dentistry, these nonrigid posts have become of the root.
quite popular. • No corrosion.
• Good esthetics with quartz and glass fiber-reinforced
posts.
• High tensile strength.
• High fatigue strength.
• Glass fiber posts can transmit curing light to internal area
of root. So, dual-cure adhesive cements can be used.
• Fiber posts are adhesively bonded in the root and
composite fiber post with composite resin core. All this
gives good bond between individual components of
monoblock.
• Biting and parafunctional habits such as clenching or • Molars: Posts are placed in
Bruxism transmit nonaxial shear, tensile and compressive – Palatal roots of maxillary molars
forces to a post in the root. – Distal roots of mandibular molars.
In case of structurally weak teeth, force concentration In distal roots of mandibular molars, the post space
in the root can predispose the root to fracture. drills larger than size #3 GG drill should not be used.
With very little amount of tooth structure remaining,
and minimal or no crown ferrule to resist force, more force Root Anatomy
will get transferred to the post. Post flexure of nonrigid posts
under occlusal loads may result in micromovement of the • Root concavities should be considered.
core that causes disruption of the cement seal and leakage Maxillary first premolars have deep mesial concavities.
or may result in loss of the core and the crown. Maxillary first molars have deep concavities on the furcal
surface.
Clinical Parameters for Post Space • Root curvatures should be considered.
Preparation and Post Selection Generally, root curvatures occur in the apical 5 mm
of the root. Therefore, when 5 mm of gutta-percha is
Apical Seal retained apically, the curved portions of the root are
It has been found that atleast 5 mm of gutta-percha is usually avoided. In case of greater curvature, limit the
required for an adequate apical seal. If less than this is left post length so as to preserve dentin, thereby preventing
behind, there are high chances of leakage. root fracture or perforation.
• Root canal shape: Maxillary premolars and mesial roots
of mandibular molars have elliptical or ribbon shaped
canals and post space preparation should be avoided in
those.
- When post length is shorter, then the success • High Compressive strength, Contrasting Color to tooth
rate has been found to be the same as for the for better distinction in posterior teeth
restoration without the post in such teeth. • Dimensional stability
– Problems with very long posts: • Ease of manipulation, Esthetics (for anterior core built-
up)
• Short Setting time.
Fig. 21.12 A mind-map to remember the clinical parameters for post space preparation and post selection
– Disadvantages:
- Low strength
- Low fracture toughness
- Low retention when preformed posts are used
- Solubility and sensitivity to moisture
- Insufficient strength to be used as core for the
tooth to serve as abutment for bridge.
• Resin-modified glass ionomer core: (Composite resin +
glass ionomer)
– Advantages:
- Moderate strength
- Satisfactory core material for moderate size built- Using Preformed Post Followed By Core Built-up
ups
- Anticariogenic • Commonly used technique nowadays.
- Higher bond strength • This system makes use of appropriate post space
- Minimal microleakage. preparation drills to prepare the post space of desired
– Disadvantages: length measured from a fixed coronal landmark till the
- Hygroscopic expansion may result in fracture of point in the root canal up to which the gutta-percha is
ceramic crowns to be removed retaining atleast 5 mm of gutta-percha
- Solubility between glass ionomer and composite apically and depending on other factors as shown in
resin. Figures 21.14A to E.
• After the post space is prepared, the post corresponding
WHAT IS THE TECHNIQUE OF FABRICATION OF to the drill is placed in the prepared space to check the
length and fit.
FOUNDATION RESTORATION?
• The extra length of the post is cut using air-rotor
Clinical procedure involves: handpiece with a water coolant.
• Step 1: Post space preparation • The post is then bonded or cemented in place as shown
• Step 2: Post and core restoration. in Figure 21.14F.
370 Short Textbook of Endodontics
A B C D E
F G H I
Figs 21.14A to I Steps involved in restoring an endodontically treated tooth using preformed-post technique: (A) An Endodontically treated
tooth with very little sound coronal tooth structure, indicated for post and core restoration; (B) Gates Glidden drill no. 1 is used to remove
the gutta-percha from the coronal third of the root; (C) Alternatively a Peeso drill can also be used for removal of gutta-percha to the desired
length so as to preserve about 3–5 mm of gutta-percha for the apical seal; (D) The post space preparation drill is used to remove the gutta-
percha to the required length; (E) This is a special drill to create a positive stop for post head/hub increasing the retention of post; (F) Post
bonded or cemented in place; (G) Core built-up; (H) Preparation of tooth to receive full coverage coronal restoration; (I) A completely restored
Endodontically treated tooth
• Core material is then placed around the post into the Cast Post and Core
remaining pulp chamber and is built-up to form the
coronal area as shown in Figure 21.14G. • Direct technique:
• The tooth is then prepared to receive a full coverage – This involves intraoral fabrication of a castable post
restoration as shown in Figure 21.14H. and core pattern on the prepared tooth.
• Figure 21.14I shows a completely restored Endodontically – Prefabricated plastic postpattern is seated in the
treated tooth. post space and autopolymerizing acrylic resin can
Restoration of Endodontically Treated Teeth 371
Coronal Coverage
• After the fabrication of the foundation restoration,
the final step in Endodontic reconstruction is coronal
coverage.
• The rule is to give a coronal coverage restoration for
most Endodontically treated posterior teeth and all
structurally damaged anterior or posterior teeth. Fig. 21.15 Causes of failure of post and core restorations
372 Short Textbook of Endodontics
22
CHAPTER
Nonsurgical Endodontic
Management
This chapter tells you about the causes of post-treatment Endodontic disease and explains in detail
how nonsurgical Endodontic retreatment can result in healing and thus saving the involved tooth.
You must know
• What is the Outcome of Endodontic Treatment?
• What are the Measures to be Employed to improve the Rate of Success of Treated
Endodontic Cases?
• What are the Causes of Endodontic Failures?
• How do you Diagnose Post-treatment Disease?
• What is the Treatment Plan for the Patient with Post-treatment Disease?
• What are the Indications and Contraindications of Endodontic Retreatment?
• What are the Factors to be Considered for Endodontic Retreatment?
• What are the Steps for Nonsurgical Endodontic Retreatment?
• What is the Prognosis of Endodontic Retreatment?
Microbial
Microbial infection persisting in the apical portion of the
root canal system is the major cause of Endodontic failure.
Intraradicular infection is the essential cause of primary
apical periodontitis and major cause of post-treatment apical
periodontitis.
Microorganisms may be left behind in the apical portion
of the complex root canal system due to improper root canal
treatment procedures.
• Use greater care in Treatment. Do not hurry, maintain an Microorganisms may be found as biofilm located
organized approach. Be certain of instrument position within small canals, lateral or accessory canals or in the
and procedure before progressing. space between root fillings and canal wall of incomplete
• Establish adequate Cavity preparation. Access cavity can obturated canal.
be improved by modifications of coronal preparation.
Radicular preparation can be improved by thorough Nonmicrobial
canal cleaning and shaping.
• Determine the exact Length of tooth to the foramen True cysts, cholesterol crystals, foreign bodies in periapical
and be certain to operate only to the apical stop, about area are the nonmicrobial causes of Endodontic failure.
0.5–1 mm from the external orifice of the foramen. Healing by scar tissue formation may be misdiagnosed
• Always use Curved, sharp instruments in curved canals, as radiographic sign of Endodontic failure.
and especially remember to clean and reshape the
curved stainless steel instrument each time it is used. Flora Associated with Root Canal Treated Teeth
• Use great care in fitting the primary filling point/Master
Cone. • Bacteria, yeasts, fungi, mixed anaerobic microbiota,
The apical portion of the canal must be obliterated. viruses, may be found.
Ensure total obturation of the entire root canal. Always use • Gram +ve cocci, rods and filaments may be the bacteria
root canal sealer cement. found.
• Use Periradicular Surgery only in those cases for which • Mostly species belonging to genera Actinomyces,
surgery is definitely indicated. Enterococcus and Propionibacterium.
• Always check the Apical density of the completed root • Enterococcus faecalis is commonly isolated from failing
canal filling of the patient undergoing periradicular root canal treated teeth and it is known to be especially
Endodontic Failures and Nonsurgical Endodontic Management 375
Fig. 22.1 Radiograph showing recurrent periapical infection in root Fig. 22.2 Recurrent periapical infection in poorly shaped and filled
canal treated mandibular premolar due to unusual anatomy canals and mesial canal blocked with separated instrument
Endodontic Failures and Nonsurgical Endodontic Management 377
Contraindications
As such, there is no absolute contraindication of Endodontic
treatment or retreatment. But teeth with the following
conditions if indicated for retreatment may have poor • Recleaning and reshaping:
prognosis: – Correct length of canal is established.
• Untreatable root resorption – Reinstrumentation and reshaping using the crown-
• Terminal periodontal disease down technique.
378 Short Textbook of Endodontics
• Gaining access through the restoration (Crown or Bridge) • Coronal disassembly: Retreatment access is called
– For access through metal, carbide fissure burs are coronal disassembly as it mostly requires removal of full
used coverage restoration or a restoration supported by post
– For access through porcelain fused to metal (PFM) and core, etc.
crowns: If there is defect or caries associated with the existing
- Round diamond bur to cut through porcelain restoration or if the treatment plan calls for a new crown,
- Transmetal bur for metal substructure the old crown is removed and replaced later.
– Copious water coolant spray and use of diamond Different devices have been manufactured for
burs are recommended during access through conservative removal of crown without damaging the
porcelain to minimize occurrence of micro- internal tooth structure. Sometimes reuse of these
fractures restorations is possible.
Endodontic Failures and Nonsurgical Endodontic Management 379
Removal of Posts
Techniques
Management of
Discolored Teeth
This chapter describes about tooth discoloration and explains in detail about ‘bleaching’, as a treatment
modality for whitening of vital and Endodontically treated teeth.
You must know
• What are the Causes of Tooth Discoloration?
• What are the Different Methods of Management of Discolored Teeth?
• What is Bleaching of Teeth?
• Why Bleaching?
• What is the Chemistry and Mechanism of Bleaching?
• Etiology of Tooth Discoloration and its Management in Detail
• What are the Indications and Contraindications of Bleaching?
• Which are the Materials Used for Bleaching?
• What is the Technique for Bleaching Vital Teeth?
• What are the Side Effects and Adverse Effects of Extracoronal Bleaching of Vital Teeth?
• What is the Technique for Bleaching Endodontically-Treated Teeth?
• What are the Side Effects and Adverse Effects of Intracoronal Bleaching of Endodontically
Treated Teeth?
• How do we Restore Intracoronally Bleached Endodontically Treated Tooth?
• What is Enamel Microabrasion?
• What is the Role of Veneers and Crowns in Management of Discolored Teeth?
WHY BLEACHING?
• Yellowish looking teeth can be whitened by means of
bleaching.
Discoloration of teeth can occur due to various
endogenous or exogenous causes as listed above in the
Etiology of tooth discoloration.
• Discolored teeth can be whitened by means of bleaching.
Thus, the goal of bleaching procedure is to restore tooth
esthetics by restoring the normal color of the tooth.
384 Short Textbook of Endodontics
Extrinsic Stains
Stains from foods, beverages, tobacco products and
chemicals from mouth rinses, toothpowders, etc. are all of Fig. 23.1 Photograph showing generalized discoloration of teeth
local origin and can be removed by scaling and polishing. due to tetracycline (Courtesy of Dr CR Suvarna)
• Posteruptive causes
a. Pulp necrosis: Most common cause of tooth
discoloration.
Several months after death of the pulp or treatment of
tooth, discoloration is noticed due to slow formation
of color producing compounds. Figures 23.2A to C
show the photographs of discolored upper right A
central incisor due to trauma causing pulp necrosis.
Photographs are taken in three different positions.
Role of bleaching: Intracoronal bleaching is effective
in these cases.
b. Intrapulpal hemorrhage:
If pulp recovers, discoloration may be reversed. B
If pulp becomes necrotic, discoloration persists
and becomes severe with time. Figure 23.3 shows
photograph of discolored maxillary central incisor
tooth.
Role of bleaching: Intracoronal bleaching is effective
in these cases.
c. Aging: Due to aging, there is decrease in thickness of
enamel due to wasting diseases of teeth — attrition,
abrasion, erosion. On the other hand, there is
increase in the thickness of dentin and changes
in optical properties of tooth due to deposition of
secondary and reparative dentin. So, the yellow color
of dentin becomes more apparent in older teeth as
shown in Figure 23.4.
Extrinsic stains are removed by scaling and
polishing and then extracoronal bleaching can be
done to restore white color of the teeth. C
d. Calcific metamorphosis: Deposition of hard tissue Figs 23.2A to C Photograph showing discolored upper right central
within the root canal space in response to trauma is incisor due to trauma causing pulp necrosis. Photograph taken in
called calcific metamorphosis. three different positions (Courtesy of Dr CR Suvarna)
386 Short Textbook of Endodontics
Fig. 23.3 Photograph showing discolored maxillary right central Fig. 23.5 Photograph showing discoloration of first premolar due to
incisor (Courtesy of Dr CR Suvarna) old silver amalgam restoration (Courtesy of Dr CR Suvarna)
A B
Figs 23.6A and B Photograph showing discolored composite
restorations: (A) Maxillary lateral incisor; (B) Mandibular first molar
(Courtesy of Dr CR Suvarna)
WHAT ARE THE INDICATIONS AND • Superoxol is a 30% solution of hydrogen peroxide by
CONTRAINDICATIONS OF BLEACHING? weight and 100% by volume in pure distilled water. It
decomposes readily in an open container, so it has to
be stored in sealed refrigerated containers.
• Hydrogen peroxide in high concentrations has ischemic
effect on skin and mucous membrane. So, these materials
should be carefully handled to avoid their contact with
tissues during handling and bleaching treatment. Figure
23.8 shows photograph of commercially available 35%
hydrogen peroxide for bleaching.
Carbamide peroxide:
• Carbamide peroxide is in the form of crystallized powder
that contains 35% hydrogen peroxide.
• It is called urea hydrogen peroxide and yields urea and
hydrogen peroxide on decomposition.
• Carbamide peroxide in the concentration of 10–30%
is used for at-home bleaching, 10% being the most
common.
• Carbamide peroxide in the concentration of 35% may
be used for in-office bleaching.
Carbopol: Some bleaching preparations contain a water
soluble polyacrylic acid polymer called carbopol.
Carbopol is added as a thickening agent.
Carbopol prolongs the release of active peroxide.
Thus, it improves the shelf life of the bleaching
preparation.
WHICH ARE THE MATERIALS USED FOR
Sodium perborate:
BLEACHING?
• Sodium perborate is available as a white powder
Bleaching is based on peroxide compounds as the active containing about 95% perborate, corresponding to 9.9%
agent. It acts as an oxidizing agent and there is formation of the available oxygen.
of free radicals and reactive oxygen molecules that attack
the long chained dark colored molecules and split them
into smaller, less colored and more diffusible molecules.
For extracoronal bleaching: Hydrogen peroxide, carbamide
peroxide are used.
For intracoronal bleaching: Sodium perborate and superoxol
are used.
Hydrogen peroxide:
• Hydrogen peroxide is a strong oxidizing agent, which
may be applied directly or be produced in a chemical
reaction from carbamide peroxide or sodium perborate.
Decomposition of carbamide peroxide and sodium
perborate releases hydrogen peroxide in an aqueous
medium.
• It is used in both in-office and at-home bleaching
materials. In-office bleaching materials have 25–38%
concentration of H2O2. At home, bleaching materials Fig. 23.8 Commercially available 35% hydrogen peroxide for
have 3–7.5% concentration of H2O2. bleaching (Courtesy of Mr Amar, Dr Dabholkar’s clinic)
Management of Discolored Teeth 389
• It is stable when dry but when exposed to acid, warm air • Indications: Figure 23.9 gives the indications for
or water, sodium perborate decomposes to form sodium extracoronal bleaching of teeth.
metaborate, hydrogen peroxide, and nascent oxygen. • Types: Extracoronal bleaching for vital teeth can be
• Depending on oxygen content, sodium perborate is carried out:
available as monohydrate, trihydrate and tetrahydrate. – By clinician in the dental clinic; in-office extracoronal
The oxygen content determines the bleaching efficacy. bleaching/chair-side bleaching/power bleaching
• Sodium perborate is safer for use as compared to – By patient at home, under the guidance and
hydrogen peroxide for bleaching. It may be mixed with supervision by dentist ; at-home extracoronal
superoxol (30% H2O2 by weight) to form a paste that bleaching.
decomposes into sodium metaborate, water and oxygen. I. Technique for in-office extracoronal bleaching of vital
• Sodium perborate is the material of choice for teeth:
intracoronal bleaching, in which it is sealed into the – Bleaching materials:
pulp chamber where it oxidizes and discolors the stain - 25–38% H 2 O 2 (35% H 2 O 2 commonly used)
slowly over a period of time, the technique commonly available in gel form is used.
referred to as walking bleach technique. - Carbamide peroxide gel (10%, 15%, 20%, 35%)
– Mode of bleaching:
WHAT IS THE TECHNIQUE FOR BLEACHING - Bleaching gel applied alone, or
VITAL TEETH? - Bleaching gel in combination with light source
Extracoronal bleaching is done for vital teeth.
- Earlier, heat, electric current and other chemicals it tends to absorb extrinsic stains faster from
were applied with bleaching gel to enhance its foods, beverages, etc. So, polishing of teeth after
bleaching efficacy. They are rarely used now. in-office bleaching is an essential step.
Light used:
Regular curing light for resin composites II. Technique for at-home extracoronal bleaching of vital
• Light-emitting diodes (LED) teeth:
• Laser light (e.g. Argon, CO2): Less popular – Bleaching materials: Hydrogen peroxide and
• Specialized light for bleaching carbamide peroxide are used as active ingredients
– Clinical procedure: for professional at-home bleaching procedure.
- First step is to record the pretreatment color of Concentration is 3–7.5% H2O2 or 10–22% carbamide
teeth (shade) using a camera (Photograph). This peroxide.
provides an excellent baseline data. – Mode of bleaching: Custom tray is manufactured for
- Diagnostic testing: Clinical and radiographic the patient. Bleaching gel is to be loaded in the tray
examination of all teeth for any possible caries, and patient wears the tray for several hours in night
defective restorations, periapical or pathologic for few days. Figure 23.10 shows photograph of soft
condition which should be treated prior to vinyl custom tray fabricated for bleaching.
bleaching. Professional bleaching strip is also available for at-
- Cleaning: Thorough scaling and prophylaxis is a home bleaching. Figure 23.11 shows photograph of
must. prefabricated bleaching trays with loaded bleaching
Prophy-jet prophylaxis will free the teeth to be material.
bleached of all surface stains and plaque. – Procedure:
- Isolation: Isolating the teeth to be bleached and - Scaling and polishing of teeth and any other
protection of gingiva and other soft tissues of the restorative treatment required by the patient is
mouth using a rubber dam, waxed dental floss, performed first.
reflective resin barrier, orabase, etc. - Upper and lower arch impressions are made.
- Protection of patient and dental team:
Surgical rubber gloves and safety glasses for the
dental staff.
Heavy plastic wrap for patient’s hands and
clothes. Safety glasses for the patient.
- Bleaching proper:
■ Rinse and remove excess varnish, jelly or
orabase from enamel of the teeth to be
bleached with pumice and water
■ Etch each tooth facially and lingually for
20 seconds with 37% phosphoric acid
■ Rinse for 30 seconds and dry the teeth
■ Apply bleaching agent: Superoxol or 35%
hydrogen peroxide with a piece of cotton
gauze, adhesive strips, paint-on or trays
■ Careful handling of bleaching material and
high vacuum suction is used
■ Position the bleaching light with an adjusted
rheostat setting. Bleaching temperature
recommended for vital teeth is 115˚C.
- After bleaching procedure, remove gauze and
flush teeth with copious amounts of warm water
Fig. 23.10 Soft vinyl custom tray fabricated over the patient’s model.
before carefully removing floss and rubber dam. Blue marked areas are to incorporate reservoirs in tray for loading
- Polish the teeth with polishing wheels. Since bleaching material (Spacer) (Courtesy of Dr Mahashabde, Rajesh
the enamel is demineralized during bleaching Shivhare’s clinic)
Management of Discolored Teeth 391
Fig. 23.12 A mind-map to remember all points of side effects/adverse effects of extracoronal bleaching of vital teeth
Management of Discolored Teeth 393
Fig. 23.14A Discolored maxillary right central incisor and mandibular left central incisor—Labial view (Courtesy of Dr CR Suvarna)
Fig. 23.14B Discolored maxillary right central incisor—Labial and palatal view (Courtesy of Dr CR Suvarna)
Fig. 23.14C Discolored mandibular left central incisor—Labial and lingual view (Courtesy of Dr CR Suvarna)
Management of Discolored Teeth 395
Fig. 23.14D Postobturation radiographs of maxillary right and mandibular left incisor teeth respectively (Courtesy of Dr CR Suvarna)
Fig. 23.14E Coronal seal achieved with glass ionomer cement after placement of bleaching material (Courtesy of Dr CR Suvarna)
Fig. 23.14F Results of intracoronal bleaching of maxillary right central incisor and mandibular
left central incisor (Courtesy of Dr CR Suvarna)
396 Short Textbook of Endodontics
Fig. 23.14G Extracoronal bleaching of maxillary and mandibular anterior teeth (Courtesy of Dr CR Suvarna)
Fig. 23.14H Result of intracoronal followed by extracoronal bleaching (labial view) (Courtesy of Dr CR Suvarna)
Fig. 23.14I Coronal seal achieved with composite restoration in both teeth (Courtesy of Dr CR Suvarna)
Management of Discolored Teeth 397
About 2–3 treatments, performed a week apart, should Use of Ultraviolet Photo-oxidation
suffice. If not, then reassess the case for correct diagnosis
of etiology of discoloration. • This technique involves placing superoxol matted cotton
Walking bleach is the method of choice for bleaching pellet into the pulp chamber followed by 2-minute
Endodontically treated teeth because: exposure to ultraviolet light.
• It is easy to perform • Bleaching result does not differ.
• Consumes less chairside time • Not carried out routinely.
• More comfortable to patient
• Requires no special equipment WHAT ARE THE SIDE EFFECTS AND ADVERSE
• Safe technique.
EFFECTS OF INTRACORONAL BLEACHING OF
ENDODONTICALLY TREATED TEETH?
Thermocatalytic Bleaching
External Cervical Root Resorption
• This technique involves placing superoxol matted cotton
pellets into the pulp chamber. The solution is activated High concentration oxidizing agent (30–35% H2O2)
by heat application either by electric heating devices or may diffuse through exposed dentinal tubules
specially designed lamps. and cementum defects
• Intermittent 5–6 minutes exposures of the tooth with ↓
heat and in-between cooling breaks, is done.
Necrosis of cementum
• Care must be taken to protect the teeth and surrounding
tissues from overheating. Protective creams such as ↓
vaseline, orabase, cocoa butter can be applied to the Inflammation of periodontal ligament
soft tissues during treatment to avoid heat damage. ↓
• Application of high concentration of H2O2 in combination
Root resorption
with heat can cause irritation to the cementum and
periodontal ligament of the tooth being bleached
Prevention: Effective isolation of tooth with rubber dam,
causing external cervical root resorption.
interproximal wedges and ligatures.
• Clinical result with this technique does not appear to
differ. So, the thermocatalytic approach is not used Management: Use of calcium hydroxide dressing for a week,
routinely. in the access cavity prepared.
398 Short Textbook of Endodontics
Fig. 23.15 A mind-map to remember all points of side effects/adverse effects of intracoronal bleaching of teeth
– Remove the rubber dam and use fine prophylactic preparation can be minimal from 0.3 mm cervically to
paste to smoothen the abraded enamel surface. 0.5 mm at the incisal edge. For severe discoloration, the
• Safety precautions: preparation has to be deeper than this.
– Excessive decalcification may occur. But, careful and • When more opaque ceramic is added in the veneer, it
judicious application of 18% hydrochloric acid does masks the undesirable tooth color but that limits the
not usually remove significant amount of enamel. display of vitality.
– Chemical burns of soft tissues can be prevented by • A more translucent ceramic allows more light
using protective barriers. transmission and reflection internally, making the
restoration more vital.
WHAT IS THE ROLE OF VENEERS AND CROWNS
IN MANAGEMENT OF DISCOLORED TEETH? Full Coverage Metal-ceramic or All-ceramic
Crowns for Discolored Teeth
Use of Composite Restoration/veneer for
Discolored Teeth • In case of severely discolored tooth or Endodontically
treated disclored tooth with considerable loss of tooth
• If composite is to be used for discolored teeth, an structure, metal-ceramic or all-ceramic restorations are
important consideration is masking of dentin shade not indicated. Now-a-days, all-ceramic restorations (metal-
only at the facial surface but also at the cervical margins free), that make use of Zirconia or Lithium disilicate have
and incisal edges. become quite popular and are being widely used to give
• The tooth should be prepared to allow a uniform pleasing esthetics, simulating natural appearance.
thickness of composite to create a polychromatic • Intra-coronal bleaching of Endodontically treated
appearance in the final result. discolored tooth followed by all-ceramic restoration
• If there is severe discoloration, the depth of preparation gives favorable result.
should allow an additional thin layer of opaque
composite to mask the dark dentin. BIBLIOGRAPHY
• The incisal edges may need to be covered with
composites in few cases extending on the palatal surface. 1. Grossman L, Oliet S, Del Rio C. Endodontic Practice, 11th edn.
Varghese Publication, 1991.pp.271-7.
2. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics, 6th edn.
Use of Ceramic Veneer/Laminates BC Decker Inc, Hamilton, 2008.pp.1383-96.
for Discolored Teeth 3. Patil R. Esthetic Dentistry: An Artist’s Science. 1st edn. PR
Publications, 2002.pp.105-7, 129.
• Ceramic laminates can be used in case of discolored 4. Torabinejad M, Walton RE. Endodontics: Principles and Practice,
teeth. If the discoloration is mild to moderate, the tooth 4th edn. Saunders, an imprint of Elsevier, 2009.pp.402-3.
24
CHAPTER
Management of Dental
Traumatic Injuries
This chapter explains the various dental traumatic injuries with their consequences and discusses the
various treatment modalities for their management including the considerations at the emergency visit.
You must know
• What are the Unique Aspects of Dental Trauma?
• What are the Consequences of a Dental Traumatic Injury?
• How do we Classify Traumatized Teeth?
• How do we Make Diagnosis in Case of Dental Traumatic Injuries?
• What are the Factors to be Considered for Treatment of Traumatized Teeth?
• What are the Different Dental Traumatic Injuries and their Management?
• Requirements for Success of Vital Pulp Therapy in Case of Traumatized Teeth
WHAT ARE THE UNIQUE ASPECTS OF DENTAL WHAT ARE THE CONSEQUENCES OF A DENTAL
TRAUMA? TRAUMATIC INJURY?
402 Short Textbook of Endodontics
HOW DO WE CLASSIFY TRAUMATIZED TEETH? Class II: Extensive fracture of crown involving enamel
and considerable amount of dentin but no pulp
• WHO classification has given following code numbers: exposure. Figure 24.2 shows photograph of fracture
873.60 Enamel fracture of maxillary left central incisor involving enamel and
873.61 Crown fracture involving enamel and dentin dentin.
without pulp exposure Class III: Extensive fracture of crown, involving enamel
873.62 Crown fracture with pulp exposure and considerable amount of dentin with pulp exposure.
873.63 Root fracture Figure 24.3 shows photograph of fracture of both
873.64 Crown-root fracture maxillary central incisors involving enamel, dentin and
873.66 Luxation pulp.
873.67 Intrusion or extrusion Class IV: Traumatized tooth becomes nonvital with
873.68 Avulsion or without loss of crown structure. Figure 24.4 shows
873.69 Other injuries, such as soft tissue laceration photograph of traumatized discolored maxillary right
• Andreasen’s modification of WHO classification: central incisor tooth without loss of crown structure.
873.64 Uncomplicated crown-root fracture without Class V: Tooth lost due to trauma.
pulp exposure
873.64 Complicated crown-root fractures with pulp
exposure
873.66 Concussion
873.66 Subluxation
873.66 Lateral luxation
• International association of Dental Traumatology
uses classification based on WHO and modified by JO
Andreasen and FM Andreasen, which is as follows:
Soft tissues
N873.69 Lacerations
N902.0 Contusion
N910.0 Abrasions
Tooth fractures
N873.60 Enamel fracture
N873.61 Crown fracture involving enamel and dentin
Fig. 24.1 Fractured incisal edges of both central incisors due to
without pulp exposure
trauma (Courtesy of Dr Manoj Ramugade)
N873.62 Crown fracture with pulp exposure
N873.63 Root fracture
873.64 Crown-root fracture
Luxation injuries
873.66 Tooth concussion
873.66 Subluxation
873.66 Extrusive luxation
873.66 Lateral luxation
873.67 Intrusive luxation
873.68 Avulsion
Facial skeletal injuries
802.20 Fracture of alveolar process of mandible
802.40 Fracture of alveolar process of maxilla
802.21 Fracture of body of mandible
802.41 Fracture of body of maxilla
• Ellis and Davey’s classification:
Class I: Simple fracture of crown involving enamel only.
Figure 24.1 shows photograph of fractured incisal edges Fig. 24.2 Trauma to maxillary left central incisor involving enamel
of both central incisors due to trauma. and dentin (Courtesy of Dr CR Suvarna)
Management of Dental Traumatic Injuries 403
Fig. 24.3 Trauma to maxillary central incisors involving enamel, Fig. 24.4 Discolored nonvital right maxillary central incisor due to
dentin and pulp (Courtesy of Dr CR Suvarna) trauma without any loss of crown structure and trauma to the left
side central incisor involving enamel and dentin (Courtesy of Dr CR
Suvarna)
Class VI: Root fracture with or without loss of crown deranged and may inhibit the nerve impulse
structure from an electric or thermal stimulus.
Class VII: Displacement of tooth without crown or root - A positive response at the initial examination
fracture may get converted to a negative response at a
Class VIII: Fracture of crown en mass subsequent visit indicating degeneration of pulp
Class IX: Fracture of deciduous teeth. or a negative response initially may get converted
to a positive response indicating healthy pulp.
HOW DO WE MAKE DIAGNOSIS IN CASE OF - To have a baseline data, these tests are performed
at the initial examination and then they are
DENTAL TRAUMATIC INJURIES?
repeated at 3 weeks, at 3, 6 and 12 months and
Correct diagnosis is based on: at yearly intervals following the accident.
• History taking: Details of the traumatic event and the - Electric pulp tests do not give predictable
relevant medical history. results in young teeth but may be useful in
• Clinical examination: elderly patients or in traumatized teeth that are
– Extraoral: Evaluate facial hard and soft tissues for undergoing premature sclerosis.
laceration, bone fracture, etc. – Laser Doppler flowmetry:
– TMJ and occlusion: Careful examination of temporo Laser Doppler flowmetry (LDF) is a valuable
mandibular joint should be done. Occlusion should diagnostic test in assessing vitality in traumatized
be checked. Abnormalities in occlusion can indicate teeth. It helps identify ‘at risk’ teeth early after trauma.
alveolar bone or jaw fracture LDF detects blood flow more consistently and earlier
– Intraoral: in traumatized teeth than the standard tests.
- Soft tissues: Evaluate oral soft tissues—Lips, • Radiographic examination:
tongue, cheek, floor of mouth, etc. for lacerations – Standard radiographs: Panoramic view (OPG), Intra-
and other injuries. Oral Periapical Radiograph (IOPA)
- Teeth and supporting tissues: Visual examination, – Many angled radiographs have to be taken for correct
tactile inspection and palpation, percussion and diagnosis.
mobility testing. – The International Association of Dental Traumatology
• Diagnostic tests: Pulpal tests recommends three angulations for radiographs of
– Thermal and electric pulp tests: traumatized teeth, including:
- May give false negative readings. This is because i. Occlusal view
due to traumatic injury, the conduction capability ii. Lateral view (from mesial or distal aspect of
of the nerve endings or sensory receptors may get tooth)
404 Short Textbook of Endodontics
WHAT ARE THE FACTORS TO BE CONSIDERED • Uncomplicated fractures of crown and their manage
ment:
FOR TREATMENT OF TRAUMATIZED TEETH?
– The uncomplicated crown fractures may involve only
Figure 24.5 gives the factors to be considered for treatment enamel or enamel and dentin, but there is no pulp
of traumatized teeth in the form of a mind-map. exposure. It is not usually associated with pain or
any symptoms.
WHAT ARE THE DIFFERENT DENTAL TRAUMATIC – If fracture involves only enamel, then selective
grinding of incisal edges in order to remove sharp
INJURIES AND THEIR MANAGEMENT?
edges is done. (Enameloplasty).
We shall discuss the following dental traumatic injuries and – Fractures involving only enamel can be very well
their management: treated using composite restorations.
• Crown fractures – If fracture involves enamel and dentin, it can also be
• Crown-root fractures treated using composite restorations. A protective
• Root fractures liner may be needed if the fracture has occurred at
• Luxation injuries deeper level approaching the pulp.
– Concussion – If the fractured fragment is available, it can be re-
– Subluxation attached by etching and bonding technique.
Fig. 24.5 A mind-map to remember all points of factors determining treatment of traumatized teeth
Management of Dental Traumatic Injuries 405
Fig. 24.6 A mind-map to remember all points of factors determining choice of treatment of complication fractured crown
Fig. 24.8 A mind-map to remember all points of vital pulp therapy for traumatized teeth
408 Short Textbook of Endodontics
preparation, thorough cleaning and shaping followed • Traditional method: A mix of pure calcium hydroxide
by obturation. powder with sterile saline (or anesthetic solution) or
• Immature tooth: ready mixed commercially available calcium hydroxide
– Apexification: is packed against the apical soft tissue using a plugger.
In case of immature teeth with open apices, and Then the remaining canal is back filled with calcium
thin dentinal walls, apexification procedure needs hydroxide to the level of root canal orifices. Access cavity
to be carried out to form a hard-tissue apical barrier is filled with a well-sealed temporary filling.
against which an effective root canal filling can be Radiograph is taken to ensure the entire canal has
done and to reinforce the weakened root against been filled.
fracture both during and after apexification. Other Patient is recalled at 3-months intervals and
details of Apexification are given in Chapter 27 “Pulp radiograph is taken to evaluate the formation of hard
Therapies”. tissue apical barrier. It may take about 3–18 months for
– Technique: Steps include: the barrier to form. If in between appointments, calcium
- Access cavity preparation: Determination of hydroxide wash out is seen, it is replaced as before.
provisional working length with the help of After the hard tissue barrier is evident on radiograph
a preoperative radiograph and confirmed and tactile sensation with an Endodontic instrument,
radiographically by placing the first Endodontic the calcium hydroxide is washed out of the canal with
instrument. sodium hypochlorite. The canal is then filled against the
- Since the dentinal walls are thin, preparation of apical stop but with careful softened filling technique
canal is performed very lightly and with copious without application of excessive lateral forces during
irrigation using 0.5% sodium hypochlorite. filling. Care must be taken to ensure that the root canal
- Canal is dried with paper points and calcium filling is completed to the level of hard tissue barrier and
hydroxide intracanal dressing may be placed for not forced beyond it.
about 1 week for disinfection of the canal. After • MTA Barrier: After the disinfection of the canal,
1 week, the further treatment can be carried out. calcium sulfate is pushed through the apex to form a
resorbable extraradicular barrier against which MTA
can be packed. MTA is mixed with sterile water and
placed into the apical 3–4 mm of the canal. Radiograph
is taken to confirm its placement. A wet cotton pellet
has to be placed against MTA plug and left for about
6 hours for MTA to set and then the entire canal can
A B C D
Figs 24.9A to D (A) Immature pulpally involved maxillary right central incisor with rubber dam in place; (B) Apical plug of MTA;
(C) Obturation completed with thermoplasticized gutta-percha; (D) Follow-up radiograph after 6 months (Courtesy of Dr Roheet Khatavkar)
Management of Dental Traumatic Injuries 409
Fig. 24.10 A mind-map to remember all points of nonvital pulp therapy for traumatized teeth
be obturated. Alternatively, the obturation can be • If the tooth can be maintained periodontally and can
done at the same appointment considering that the allow for a well sealed coronal restoration, then the tooth
tissue fluids of open apex will provide moisture for is treated as crown fracture.
MTA to set.
Figures 24.9A to D shows the radiographs of maxillary Root Fractures
right central incisor tooth in which apexification has Root fractures involve the cementum, dentin and pulp.
been done using MTA. • According to the level of fracture, root fractures can be
A mind-map to remember nonvital pulp therapy for classified as:
traumatized teeth is given in Figure 24.10.
• According to the direction of fracture, root fractures can • Consequences of treatment: At follow-up visits, it may be
be classified as: found that:
iii. Transition from negative to positive response replacement resorption and further dentoalveolar
may occur if circulation is restored. ankylosis. Objective of treatment is to prevent such
iv. Persistence of negative response can be complications. Severely intruded tooth may require
considered to be a sign of irreversibly damaged surgical access to attach orthodontic appliances for
pulp and Endodontic treatment is indicated. extrusion of tooth.
– Immobilize the injured teeth using a splint. – Primary tooth: If it gets intruded, it usually re-erupts
– Relieve the occlusion by selective grinding of cusps but may deviate the path of the permanent tooth bud.
of opposing teeth. So, immediate treatment may be needed.
Lateral luxation and extrusive luxation:
– If displacement of tooth (Luxation) occurs without Tooth Avulsion
fracture:
a. Immediate management: Reposition the tooth Also called total luxation or exarticulation. It is the complete
as soon after the accident as possible and displacement of the tooth out of the socket.
place a functional splint. Anesthesia needs to Tooth avulsion is treated by replantation, which refers
be administered and then reposition the tooth to replacement of tooth in its socket, with the object of
with minimal force by moving it coronally (out attaining reattachment when the tooth has been completely
of buccal bone plate) and then apically (into its avulsed from its socket.
original position). • Management of an avulsed tooth: Management of an
Splint can be removed in 2 weeks. avulsed tooth considers the following factors:
b. Late: Orthodontic treatment.
– Evaluate the width of apical constriction at the time
of repositioning.
- If width is 1 mm or more: It is considered that
revascularization will occur.
No treatment, but tooth kept under observation.
- If width is less than 1 mm: Root canal treatment
should be initiated immediately.
Intrusive luxation: Most severe traumatic injury. Ideally, an avulsed tooth must be replanted as soon as
– Immature tooth: May re-erupt and revascularization possible and should be functionally splinted.
may occur. Observe for 4–6 weeks. If re-eruption • Management of an avulsed tooth with extraoral dry time
stops before normal occlusion is attained, then of less than 60 minutes and with a closed apex:
orthodontic treatment is started to prevent ankylosis. – Rinse the root with water or saline
– Mature tooth: Pulp necrosis generally occurs. – Replant the root in the socket gently
Endodontic treatment is indicated. Severe – On second visit (after 7–10 days) consider Endodontic
injury to PDL can lead to complications such as treatment.
412 Short Textbook of Endodontics
– Obturation can be done immediately if clinical and If decision is made to replant it, it is recommended
radiographic examinations do not indicate pathosis that Endodontic treatment be performed extraorally and
– But if signs of resorption are present, long-term seal the blunderbuss apex and then replant it.
calcium hydroxide therapy can be given until an If Endodontic treatment is not possible at the
intact lamina dura can be traced emergency visit and the avulsed immature tooth has
– After obturation of root canals, tooth should receive a been replanted, then the apexification procedure is
permanent restoration as soon as possible to obtain initiated in the second visit.
a good coronal seal Adjunctive therapy: It involves:
– Follow-up visits at 3 months, 6 months and – Administration of antibiotics:
12 months. - At the time of replantation and before Endodontic
• Management of an avulsed tooth with extraoral dry time treatment
of less than 60 minutes and with an open apex: - Tetracycline affects the motility of osteoclast and
– It is recommended to soak the avulsed tooth in reduces the effectiveness of collagenase
doxycycline or cover it with minocycline for about - Penicillin V can also be beneficial
5 minutes and then rinse off the debris gently. – Chlorhexidine rinses for 7–10 days to control the
– Replant the tooth in the socket gently bacterial content of the sulcus
– In case of an avulsed tooth with open apex, the – Administration of analgesics if required.
revascularization of the pulp and continued root Physiologic storage media for avulsed tooth if
development are expected. immediate replantation is not possible: If the avulsed
– But if signs of infection appear, then apexification tooth cannot be replanted immediately, the tooth
procedure followed by Endodontic treatment is should be placed in physiologic storage solution in
indicated and performed in the second visit which order to have an extended extraoral time to minimize
is after 7–10 days. resorption complications after replantation.
• Management of an avulsed tooth with extraoral dry time Examples of such physiologic storage media in order
of more than 60 minutes and with a closed apex: of preference are:
– It is recommended that all the remaining periodontal – Hank’s balanced salt solution (HBSS): It is a pH
ligament cells be removed from the root in order to preserving fluid that can keep the periodontal
make it resistant to resorption and slow down the ligament cells viable for 24 hours.
ankylosis, on replantation. – Milk
This is done by: – Saliva
– Soak the avulsed tooth in etching acid for 5 minutes – Physiologic saline
– Then soak it in 2% stannous fluoride for 5 minutes – Water.
– Replant the tooth in the socket gently Water is least desirable storage medium because the
– Extraoral Endodontic treatment may be performed hypotonic environment of water may cause rapid cell
in the avulsed tooth before replanting it, under lysis and hence there may be increased inflammation
absolutely aseptic conditions on replantation.
But, this step has not been found to have any Outcome of replantation:
advantage. – If extraoral dry time is less than 15–20 minutes,
– After 7–10 days, Endodontic treatment and other periodontal healing is expected to occur. The
considerations similar to teeth with extraoral time PDL cells maintain their viability and repair after
less than 60 minutes. replantation with minimal destructive inflammation.
• Management of an avulsed tooth with extraoral dry time – If extraoral dry time has been more and excessive
of more than 60 minutes in a tooth with open apex: Due drying has occurred before replantation, the damaged
to potential complications involved with replantation periodontal ligament cells elicit a severe inflammatory
of such teeth, whether to replant such teeth or not is response, large area of root surface gets affected
controversial. that has to be repaired by new tissue. Replantation
Management of Dental Traumatic Injuries 413
Injury Management
Enamel fracture Enameloplasty, fragment reattachment, composite
Enamel and dentin fracture Fragment reattachment, composite, pulp protection
Pulp exposure Pulp capping, pulpotomy, apexification, RCT, composite, crown
Nonvital tooth RCT, composite, crown
Lost (Avulsion) - Replantation and splinting for 2–3 weeks;
OR
- Replacement of missing tooth: RPD/FPD; implant
Root fracture Coronal third—Orthodontic extrusion or crown lengthening, core-build, crown; extraction (poor prognosis)
Middle third—Splinting for 3 months, RCT
Apical third—Splinting for 1 month, RCT (good prognosis)
Displacement without fracture Lateral luxation, extrusion: Immediate—repositioning; late—orthodontic movement
Intrusion—observe for re-eruption 4–6 weeks, orthodontic treatment
If nonvital, RCT
En masse crown fracture Extraction; orthodontic extrusion or crown lengthening, core-build, crown (poor prognosis)
Traumatic injuries to primary teeth Avulsion—no replantation as ankylosis may develop
Intrusion—usually re-erupt; may deviate path of permanent tooth bud
Root fractures—coronal and middle third- extraction
Crown en masse fracture—extraction
Displacement—immediate-repositioning, late- extraction
Splint for less period (2 weeks)
Endodontic-Periodontal
Inter-relationships
This chapter deals with various aspects of Endodontic-Periodontal inter-relationships, the differential
diagnosis of the disease process and the appropriate treatment modality for the same.
You must know
• How are Endodontic and Periodontal Tissues and their Diseases Inter-Related?
• What are the Etiologic Factors and Contributing Factors causing Endodontic-Periodontal
Diseases?
• How do we Classify Endodontic-Periodontal Lesions?
• How to Detect Endodontic Periodontal Lesions?
• What Differential Diagnosis will you Consider when you see Features of Both Endodontic
and Periodontal Lesions?
• Which are the Different Types of Endodontic-Periodontal Lesions?
• What are the Treatment Alternatives in case of Endodontic-Periodontal Lesions?
• What is the Prognosis of a Tooth with both Endodontic and Periodontal Disease?
HOW ARE ENDODONTIC AND PERIODONTAL Pathways of communication between pulp and periodontium:
A. Physiologic modes of communication:
TISSUES AND THEIR DISEASES INTER-RELATED?
1. Apical foramen
The tooth, its pulp and its supporting structures together 2. Lateral canals, accessory canals and furcation canals
constitute a ‘biologic unit’. The pulp and the periodontium 3. Exposed dentinal tubules: When cementum and
evolved from the same mesenchymal tissue during the enamel do not meet at CEJ, dentinal tubules remain
formative stage. Except for enamel, which is an ectodermal exposed acting as pathway of communication
derivative, all the other dental structures are formed by between the pulp and the periodontium.
neural crest cells that later condense in developing maxilla B. Pathologic modes of communication:
and mandible as dental papilla and dental follicle. The 1. Exposed dentinal tubules in areas devoid of
dental papilla gives rise to the dental pulp and the dental cementum due to:
follicle gives rise to the periodontal structures. a. Developmental defects such as palatogingival
Thus, the pulp and the periodontium are embryologically groove, cervical enamel projections
and structurally related. b. Root caries
2. Idiopathic root resorption
Intercommunication between Pulp and 3. Pathologic root perforations
4. Vertical root fractures (VRF)
Periodontal Tissues
5. Trauma
There are intimate anatomic and vascular connections C. Iatrogenic:
between the pulp and periodontium through various 1. Exposed dentinal tubules following periodontal
pathways as given here. therapy such as root planning
Endodontic-Periodontal Inter-relationships 415
2. Accidental perforations during Endodontic treatment during root canal treatment procedures. Fungi are found
3. Surgical procedures. in subgingival plaque.
• Viruses: Viruses have also been found associated with
Inter-relationship between Diseases of the Pulp both Endodontic and Periodontal diseases. Herpes
Simplex virus has been isolated from the gingival
and the Periodontium
crevicular fluid and gingival biopsies of the periodontal
• Endodontic lesions can cause periodontal lesions lesions. Pulpal and associated periapical disease
Inflammatory products from diseased pulp, necrotic containing human cytomegalovirus and Epstein Barr
debris, bacterial by products and toxins virus have been found in few clinical studies. Herpes
Through apical foramen and lateral and accessory canals simplex virus has not been detected in periapical
↓ lesions.
Inflammation in periodontium involving PDL only or (The microbiology of root canals has been discussed
tooth socket and surrounding bone in detail in Chapter 6 Endodontic Microbiology).
Toxic irritants of periodontal tissue destruction migrate
towards gingival margin: Retrograde periodontitis. Contributing Factors
• Periodontal lesions can cause Endodontic lesions • Inadequate Endodontic treatment: Poor Endodontic
treatment results in treatment failure contributing to
Endodontic-periodontal disease.
• Traumatic injuries of teeth may involve the pulp
and even the surrounding periodontal attachment
apparatus. Traumatic injuries and their management
has been discussed in detail in Chapter 24.
• Coronal leakage: Coronal leakage has been found to be
one of the major causes of Endodontic treatment failure.
Endodontically treated teeth may get contaminated by
microorganisms due to defective restorations or delay in
placement of coronal restoration. An adequate coronal
One of the main goals of Endodontics is to cure apical restoration is essential to prevent coronal leakage.
periodontitis. Thus, Endodontics may be thought of as • Root Perforations: May be pathologic caused due to
periapical Periodontics. extensive carious lesion, resorption, etc. or may be
iatrogenic (Operator error during post preparation or
WHAT ARE THE ETIOLOGIC FACTORS access preparation or root canal instrumentation.) It can
lead to periodontal lesions. Sealing of the perforation
AND CONTRIBUTING FACTORS CAUSING
as early as possible and infection control is important
ENDODONTIC-PERIODONTAL DISEASES? for good prognosis. Mineral trioxide aggregate (MTA) is
Etiological Factors widely used perforation repair material.
• Developmental malformations: Radicular invaginations
• Bacteria: Root canal flora consists of proteolytic found in central fossa of maxillary central and lateral
bacteria and anaerobic microbiota. Spirochetes are incisors crossing cingulum and continuing till the root
associated with both periodontal (subgingival plaque) can lead to untreatable periodontal condition when its
and Endodontic diseases (root canals). The spirochetes epithelial attachment is breached, resulting in infrabony
Treponema denticola and Treponema maltophilum pocket formation. This condition may get associated
have been isolated from root canals. Porphyromonas with Endodontic disease.
gingivalis, Bacteroides forsythus, Prevotella intermedia, (Remember the sentence: Contributing To Endo-Perio
etc. are few periodontal pathogenic bacteria. Disease: Coronal Traumatic Endodontic Perforations
• Fungi: Fungi mainly Candida albicans is found both in Developmental).
Endodontic and periodontal lesions. Fungi may enter Figure 25.1 is the mind-map listing the etiologic and
the root canals from oral cavity due to poor asepsis contributing factors for Endodontic-periodontal disease.
416 Short Textbook of Endodontics
Fig. 25.1 Mind-map of etiologic and contributing factors causing Endodontic periodontal diseases
HOW DO WE CLASSIFY ENDODONTIC- determines the type of therapy required and probable
PERIODONTAL LESIONS? prognosis of the case.
• Tracing sinus tract or fistula, if present. Mostly related radiographic and histopathological findings. These should
to a pulpal problem. be considered for differential diagnosis.
• Pocket probing: Pocket relates to a periodontal problem A very simplified table to explain these similarities and
if the tooth is vital. But in case of pocket associated with differences which is as follows: (Cohen’s ‘The Pathways of
a nonvital tooth, there is possibility of an Endodontic Pulp’– 9th Edition’, p. 657).
problem. Long and narrow pocket related to a single
isolated tooth is suggestive of Endodontic problem. Endodontic disease Periodontal disease
Pockets with wide entrance are suggestive of periodontal • Clinical findings:
problem. – Etiology Infection of pulp Infection in
• Probing of furcation defect, if any. Usually related to periodontium
periodontal disease. – Vitality of tooth Nonvital Mostly vital
• Tooth mobility-determination. Mobility involving – Any restoration Deep or extensive Not related
multiple teeth other than the involved tooth, is more – Local irritating Not related Primary cause
related to Periodontal problem. factors:
Plaque, calculus
Radiographic examination – Inflammation Acute, sometimes chronic Chronic
• Extent of caries or restorations. – Periodontal Single, narrow Multiple, wide
• Status of any Endodontic treatment done in the tooth pockets coronally
• Condition of periradicular tissues: Thickness of PDL, – pH value Often acidic Usually alkaline
changes in alveolar bone such as bone loss
– Trauma Primary or secondary Contributing factor
• Root resorption
– Micro- Few Complex
• Wide periapical radiolucency may be suggestive of
organisms
pulpal problem. Crestal bone loss, horizontal or vertical
• Radiographic findings:
bone loss is suggestive of periodontal problem.
• Gutta-percha point inserted in the sinus tract and – Pattern Localized Generalized
radiograph taken, helps to identify the source of – Bone loss Wider apically Wider coronally
infection. – Periapical Radiolucency Not often related
– Vertical bone Absent Present
WHAT DIFFERENTIAL DIAGNOSIS WILL YOU loss
CONSIDER WHEN YOU SEE FEATURES OF BOTH • Histopathological findings:
ENDODONTIC AND PERIODONTAL LESIONS? – Junctional No apical migration Apical migration
epithelium
Clinical signs and symptoms and radiographic evaluation – Granulation Apical (minimal) Coronal (larger)
help the clinician to rule out different diseases: tissue
It may be: – Gingiva Normal Some recession
• Primary Endodontic or Periodontal lesion with
• Treatment Root canal treatment Periodontal treatment
secondary involvement resulting in a combined lesion.
• Vertical root fractures: Difficult to diagnose as it may not
be detectable by clinical inspection and radiographic
WHICH ARE THE DIFFERENT TYPES OF
examination unless the root fragments have separated.
Exploratory surgical exposure of the root for direct visual
ENDODONTIC-PERIODONTAL LESIONS?
examination can give definitive diagnosis. Primary Endodontic Lesions
• Developmental grooves: Such as palatogingival grooves
found in maxillary central and lateral incisors should be • Deep caries, extensive restorations or traumatic injury
looked for as it might have caused the defect. Localized associated with pulpal involvement may lead to
Periodontal destruction occurs due to such grooves. Pulp Endodontic pathology. The inflammatory components
of such teeth may become secondarily involved. may pass through the apical foramen or lateral/
There are certain similarities and differences in the accessory canals and produce mild inflammation at the
pulpal and Periodontal diseases in terms of clinical, apex or near the opening of the lateral/accessory canals.
Endodontic-Periodontal Inter-relationships 419
• A deep solitary pocket in the absence of true Periodontal • Treatment: Root canal treatment. Primary Endodontic
disease is indicative of lesion of Endodontic origin as lesions usually heal following root canal treatment.
shown in Figure 25.2. The sinus tract extending into the gingival sulcus or
• This pocket is a sinus tract from pulpal origin that opens furcation area quickly heals by itself following root canal
along PDL area through lateral accessory canals and treatment.
apical foramen. • Prognosis: Excellent prognosis. The periapical lesion
• There is no increase in probing depth around the tooth usually resolves if proper Endodontic therapy is done.
except in the area of sinus tract.
• Also, a sulcular pocket of Endodontic origin is typically Primary Endodontic Lesions with Secondary Periodontal
very narrow compared to pocket of Periodontal origin. Involvement
• Figure 25.2 shows diagrammatic representation of • When lesion of Endodontic origin is not treated
mandibular molar showing deep carious lesion with ↓
infected/necrotic pulp. This lesion has primarily an Pathosis continues to progress causing break-down of
Endodontic etiology. It shows the various pathways for surrounding hard and soft tissues.
the spread of infection that include: Figure 25.3 shows diagrammatic representation of an
– from apex to gingival sulcus Endodontically involved mandibular molar tooth. There
– from apex to furcation area is spread of infection through apical foramen and deep
– from lateral canals to gingival sulcus solitary pocket is formed.
– from lateral canals to furcation area • Root perforation during root canal treatment also causes
• Diagnosis: The origin of the lesion can be traced by secondary Periodontal involvement.
inserting gutta-percha cone into the sinus tract and • Root fractures also mimic the appearance of primary
taking radiographs. Also, based on findings such as Endodontic lesions with secondary Periodontal
minimal amount of plaque or calculus present, necrotic involvement. Frequently occurs on Endodontically
pulp of the involved tooth. treated teeth with large post.
Fig. 25.2 Mandibular molar with deep carious lesion. Various Fig. 25.3 a. Spread of infection from an Endodontically involved
pathways for the spread of infection denoted by arrows. a. from tooth through the apical foramen; b. Deep solitary periodontal
apex to gingival sulcus; b. from apex to furcation area; c. from lateral pocket formation
canals to gingival sulcus; d. from lateral canals to furcation area
420 Short Textbook of Endodontics
Fig. 25.4 Radiograph showing Periodontal Fig. 25.5 The tooth has no carious lesion and reveals a vital pulp.
lesion in maxillary molar There is primarily Periodontal involvement. a. Periodontal pocket;
b. Infection can spread to the pulp through the apical foramen
Endodontic-Periodontal Inter-relationships 421
This can happen when treatment procedures like scaling, • Treatment : Both Endodontic and Periodontal
curettage or surgical flap procedures open the dentinal treatment.
tubules and lateral canals to the oral environment. This After a definitive diagnosis is established, Root
results in pulp inflammation and necrosis. canal treatment and/or required Periodontal therapy is
• Signs and symptoms of pulpal disease as well as considered in the treatment plan. Generally Endodontic
Periodontal disease become evident. treatment should precede Periodontal therapy.
• Treatment of lesions that are primary Periodontal and • Prognosis depends on the amount of Periodontal
secondary Endodontic involvement: destruction. Prognosis is guarded in single-rooted teeth.
– Endodontic treatment
– Periodontal procedures such as Scaling and root
planning
– Periodontal flap surgery may be required in few
cases.
– In certain conditions like localized Periodontal
defect associated with Endodontically untreatable
tooth or iatrogenic errors causing Endoperio lesions,
certain treatment alternatives need to be considered
such as Root resection/amputation or guided tissue
generation (GTR), discussed later in this chapter.
A B
Figs 25.7A and B Radiographs of mandibular first molar with both—severe Periodontal lesion and Endodontic involvement
422 Short Textbook of Endodontics
Regenerative Technique
Guided tissue regeneration (GTR) barrier membranes can be
used in case of large periradicular lesions to promote bone
healing after Endodontic surgery. Bone replacement grafts
using guided tissue and bone regeneration techniques re-
establish the biologic structures that were lost during the
disease process.
Endodontic-Periodontal Inter-relationships 423
Prognosis may be better in molar teeth if all the roots the tooth as per the type of Endodontic-Periodontal lesion
have not suffered loss of supporting tissues. Root resection is given in the above table.
can be considered as treatment alternative.
BIBLIOGRAPHY
WHAT IS THE PROGNOSIS OF A TOOTH
WITH BOTH ENDODONTIC AND 1. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis:
Mosby; 2006.pp.650-65.
PERIODONTAL DISEASE? 2. Franklin S Weine. Endodontic therapy, 6th edn. Mosby-Affliate
Long-term prognosis will be determined by correct of Elsevier, St Louis, Missouri; 2004.pp.452-80.
diagnosis of the etiology of disease process whether 3. Grossman L, Oliet S, Del Rio C. Endodontic Practice, 11th edn.
Endodontic, Periodontal or combined. The prognosis of Varghese publication; 1991.pp.313-27.
4. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics 6, 6th edn.
BC Decker Inc, Hamilton; 2008.pp.638-56.
26
CHAPTER
Surgical Endodontics
This chapter discusses in detail the various aspects of periradicular surgery including the basic principles
and step-by-step procedure for performing the surgery.
You must know
• What is Endodontic or Periradicular Surgery and what are its Objectives?
• What are the Indications of Periradicular Surgery?
• What are the Contraindications of Periradicular Surgery?
• What is the Contemporary Classification of Endodontic Surgery?
• What are the Important Considerations While Case Selection and Treatment Planning for
Periradicular Surgery?
• What are the basic Principles and Steps to be followed in Periradicular Surgery?
• When the apical constricture of the root canal has been WHAT ARE THE CONTRAINDICATIONS OF
destroyed by uncontrolled instrumentation resulting in PERIRADICULAR SURGERY?
apical foramen that cannot be adequately sealed with
orthograde filling.
• For the removal of the foreign body such as extruded
filling, cement, instrument from the periradicular
area that has resulted in the origin or extension of
periradicular disease,
• In case of exacerbation of disease during nonsurgical
treatment or in case of persistent and unexplainable
pain following completion of nonsurgical treatment.
• When there is excessively large and intruding
periapical lesion that may require marsupialization
and decompression procedures for treatment.
• In case of a horizontally fractured root tip associated
with a periradicular disease.
• Failure to heal in spite of good nonsurgical Endodontic
treatment.
(Friends, we can remember the above indications by
using a simple alphabetic formula:
a2b2cde2f2
Where a = access, a = apical, b = biopsy, b = blunderbuss,
c = constricture, d = disease, e = exacerbation, e =
excessive, f = fracture, f = failure)
But, with the recent advances in the field of
Endodontics in terms of improved visualization with
microscope, increased knowledge and improved
materials has made primary nonsurgical treatment
and nonsurgical retreatment more predictable with
increased rate of success. As a result, today there are
specific indications for periradicular surgery.
Ingle has given the following specific indications for
periradiclar surgery:
– When nonsurgical retreatment has failed, that
implies that nonsurgical treatment had been
employed atleast twice.
– When the initial or primary nonsurgical treatment
provided has failed and retreatment is not possible
or practical to achieve a better result.
– When a biopsy is necessary.
Surgical Endodontics 427
Anatomic Considerations
Important anatomic structures that may be encountered
during Endodontic surgery and the anatomy of the
individual root and root canal system should be considered.
– Clinician must be prepared for the management and Considerations in Anterior Mandible
precautions to be taken when the maxillary sinus • Roots of mandibular incisors are lingually inclined.
gets exposed during Endodontic surgery in case of • Vestibule is shallow in the region of mandibular incisors.
a large periradicular lesion. Sinus opening should • Roots of adjacent teeth are quite close to each other.
be temporarily occluded with appropriate material
and prevent the inadvertent displacement of infected Considerations in Posterior Mandible
root fragments and debris into the sinus. • Position of mental foramen: It may be located between
• Palatal roots: Surgical access to the palatal roots of the apex of mandibular first premolar and the mesial
maxillary molars may be difficult. They can be accessed root of the mandibular first molar.
by palatal or buccal (transantral) approach. • Relationship of the root apices to the mandibular canal.
• Greater palatine foramen: Generally located about • Neurovascular bundle within the mandibular canal that
1 cm from the margin of palatal gingiva in between exits through the mental foramen.
the maxillary second and third molars. This anatomic • Depth of vestibule in mandibular posterior teeth.
structure is usually not encountered as very few apical • Distal root of mandibular second molar is located
surgical procedures are performed on the palatal roots quite away from buccal cortical plate, meaning that
of maxillary 2nd or 3rd molars. mandibular second molar has quite thick overlying
• Anterior palatine artery: Emerges from greater palatine buccal bone and more buccal location of mandibular
foramen distal to maxillary 2nd molar. Its position canal, all these factors cause difficulty in access to the
should be carefully considered to avoid severing roots of mandibular second molar.
it during incision. But in case if it gets severed, it A mind-map to remember all points of anatomic
should be locally clamped and pressure applied for considerations for periradicular surgery is given in
hemostasis. Figure 26.1.
Fig. 26.1 A mind-map to remember all points of anatomic considerations for periradicular surgery
Surgical Endodontics 429
• There should be continuous curvatures between the Generally used in cases when no underlying
horizontal and vertical incisions. Sharp angles may tear. periodontal problems are present.
• When sinus tract is present, it should be included in the It is also called submarginal curved flap.
flap. It is not recommended for periradicular
• Releasing incisions should not be over bony eminences surgery due to its disadvantages such as poor
but between them, as their overlying tissue is thin and surgical access, poor wound healing, etc.
it may get stretched and tear when sutured. – It can be submarginal scalloped rectangular
• Whenever possible, the sutured flap margins must rest flap: Luebke-Ochsenbein flap is formed by
on solid cortical bone plate. two vertical incisions connected by a scalloped
Periradicular surgical flaps can be of 2 types: submarginal horizontal incision in the attached
1. Full mucoperiosteal flap: Involves an intrasulcular gingiva as shown in Figure 26.7.
horizontal incision in which the marginal and This flap gives the advantage of both-vertical
interdental (papillary) gingival tissues are reflected flap and semilunar flap. Can be used in case of
as the part of the flap. It is also called as papillary maxillary teeth where there is adequate amount
based flap. of attached gingiva.
– It can be triangular flap formed by horizontal
intrasulcular incision and one vertical releasing Flap Reflection and Flap Retraction
incision as shown in Figure 26.2. Single In this step, soft tissues such as gingiva, mucosa and
vertical releasing incision causes limited surgical periosteum are separated from the surface of the alveolar
access. bone using a periosteal elevator.
– It can be rectangular flap formed by horizontal,
intrasulcular incision and two vertical releasing
incisions as shown in Figure 26.3. This provides
good surgical access and may be indicated
in case of mandibular anterior teeth or when
multiple teeth are involved. There is difficulty
in reapproximation of flap margins with this
design.
– It can be trapezoidal flap, which is similar to
rectangular flap but an obtuse angle is formed
where the vertical incision intersects the
horizontal and intrasulcular incision as shown in
Figure 26.4. There is possibility of severing vital
structures and increased bleeding with this flap Fig. 26.2 Triangular flap design
design. So, it is contraindicated in periradicular
surgery.
– It can be horizontal or envelope flap created by
horizontal and intrasulcular incisions but there is
no vertical releasing incision as shown in Figure
26.5. It provides limited access. It may be used in
case of cervical defects, hemisections, etc.
2. Limited mucoperiosteal flaps: These flaps have a
submarginal, i.e. subsulcular horizontal incision. It
does not include marginal or interdental tissues.
– It can be semilunar flap formed by giving a curved
incision in the attached gingiva and the alveolar
mucosa as shown in Figure 26.6. Its horizontal
component rests on alveolar bone structure
about 3 mm apical to gingival crest and ends in
attached gingiva. Fig. 26.3 Rectangular flap design
432 Short Textbook of Endodontics
of cortical and cancellous bone may have to be removed to into the soft tissue mass to prevent any possible discomfort
gain access to the root end which can be difficult as exact during the process of debridement and for the purpose of
location of bony window needs to be determined to prevent hemostasis.
unnecessary removal of bone. Use of a radiopaque marker • Periradicular curettage is done to:
can serve as a guidance to determine the position of root – To remove pathologic tissue associated with root
apex. apex such as cyst, granuloma, etc.
• Principles that should be followed during hard tissue – To remove any foreign material that had got extruded
surgical access include: in the periapical area.
– Preservation of healthy bone as much as possible. – To provide visibility and accessibility to facilitate
– Controlling the heat generated during the process. root-end procedures.
• Hard tissue surgical access is achieved using a round bur • Biopsy is done for the histopathologic assessment of the
in a high speed handpiece with adequate water coolant. pathologic soft tissue removed.
– It is important that high speed handpiece that is used • Technique
should exhaust air from the base rather than the – Place an appropriate size curette between the
cutting end in order to avoid the risk of air embolism. soft tissue mass and the lateral wall of the bony
– Round bur is used to remove bone as it readily allows crypt.
access of coolant to the cutting surface so that there – Then apply pressure against the bone as the curette
is minimal inflammation and favorable wound is inserted between the soft tissue mass and bone
healing. Bone covering the root should be slowly around lateral margins of lesion.
and carefully removed using the round bur in gentle – The soft tissue mass, if possible, can be removed from
brush stroke action working in an apical direction the bony crypt in one piece to facilitate periradicular
until the root end is identified. curettage.
– Use of adequate coolant is essential to control the – The curette detaches the soft tissue mass from the
heat generated during bone cutting and to clear walls of the crypt, then a pair of tissue forceps can be
off the debris accumulated on the cutting flutes of used to grasp the soft tissue mass and immediately
instruments. it is put in a bottle containing 10% buffered formalin
• Technique involves creating a window by preparing 3 solution and submitted for biopsy.
openings in the bone, two of the openings through the – The curette is then used in scraping motion to
cortical plate adjacent to mesial and distal sides of root remove the remaining soft lesion if any from the
near its apical third and third opening slightly beyond medial wall of the osseous defect.
the apex. After completing initial access, extension of
window can be done using hand instruments such as Step 5: Management of Hemorrhage from
chisels as they are less likely to gouge the root.
the Surgical Site
• Next step is to distinguish the root apex from the
surrounding bone by following ways: • Hemorrhage occurs during curettage and following root
– Radiograph can be taken to serve as the “road map” end resection which can obstruct vision and prevent
– Color: Root structure appears more yellowish as careful evaluation of the root end and the further root
compared to bone. end procedures.
– On probing, there is no bleeding from root. • Hemostasis can be achieved by:
– Texture: Bone has granular and porous texture. Root – Presurgical local anesthetics and vasoconstrictors
has smooth and hard texture. – Use of local hemostatic agents in the surgical site.
– Staining dye can be used to identify the periodontal • Local hemostatic agents control hemorrhage from small
ligament surrounding the root. blood vessels and capillaries by forming an occlusive
clot, either by exerting a physical tamponade action
Step 4: Periradicular Curettage and Biopsy or by enhancing the clotting mechanism.
• Sponges or cotton pellets soaked in a vasoconstrictor
It is recommended that prior to periradicular curettage, such as racemic mixture of epinephrine hydrochloride
local anesthetic containing a vasoconstrictor be injected can be used as a local hemostatic agent.
434 Short Textbook of Endodontics
Pulp Therapies
This chapter describes the various vital pulp therapy techniques—current concepts and materials used
and also describes apexification.
You must know
• What is Vital Pulp Therapy?
• What are the Objectives of Vital Pulp Therapy?
• What are the Techniques and Materials used for Vital Pulp Therapy?
• What are the Hemostatic Agents and Antimicrobial Materials used in Vital Pulp Therapy?
• What is the Criteria for Case Selection for Vital Pulp Therapy?
• What is Apexification (Nonvital Pulp Therapy)?
• Materials used:
– Calcium hydroxide
– Zinc oxide eugenol
• Rationale of indirect pulp capping: Rationale is
based on the finding that when there exists a zone
of demineralized affected dentin between the outer
infected dentin and the pulp, infected dentin is removed
and the affected dentin that is left behind remineralizes
and the odontoblast form reactionary dentin, so that
pulp exposure is avoided. Few viable bacteria that
remain in the deeper layers of dentin are inactivated
when cavity is sealed properly and pulp exposure
prevented. Thus vitality of pulp is preserved.
• Mechanism:
• Objectives:
– The interim or final restoration should seal completely
the involved dentin from the oral environment
– Vitality of tooth should be preserved
– Absence of post-treatment signs or symptoms such
as sensitivity, pain or swelling.
– No radiographic evidence of internal or external root
resorption or other pathologic changes.
– Immature teeth with open apex should show • Indirect pulp capping is not a predictable treatment
continued root development and apexogenesis. option for permanent teeth due to following reasons:
• Indications: – Difficulty in determining at what depth, caries
– Teeth with deep caries but free from symptoms of excavation should be halted.
painful pulpitis – As remineralization occurs, carious dentin becomes
– No spontaneous pain dry and loses volume that results in voids under the
– No tenderness to percussion restorative material.
– No abnormal mobility – The dormant lesion may get rapidly reactivated in
– No radiographic evidence of radicular disease case of restoration failure.
– No internal or external root resorption detectable • Technique:
radiographically. First visit
• Contraindications: After profound anesthesia and isolation with rubber
– Teeth with deep caries with signs and symptoms of dam,
painful pulpitis Step 1: Large round bur #6 or #8 is used to excavate caries
– History of spontaneous pain under adequate water cooling. Careful judicious use
– Tenderness to percussion of spoon excavator can be made for caries excavation
– Abnormal mobility as its use in deep carious lesions may remove large
– Radiographic evidence of interradicular bone loss. segment of carious dentin.
Pulp Therapies 441
A B C
Figs 27.2A to C Steps of indirect pulp capping: (A) Mandibular first molar showing deep occlusal and proximal caries approaching the
pulp; (B) All caries is excavated except that is just overlying the pulp and is covered with calcium hydroxide sub-base and the tooth is sealed
externally with hard-setting zinc oxide eugenol or amalgam may be placed as an interim restoration. a: Zinc oxide eugenol; b: Calcium
hydroxide sub-base; c: Affected dentin; d: Pulp horn; (C) After about 6–8 weeks the tooth is re-entered. Deposition of reactionary dentin is
found beneath the caries that allows eradication of remaining caries without causing pulp exposure. Cavity preparation is completed and a
fresh layer of calcium hydroxide is placed as sub-base, which is covered with zinc oxide eugenol or zinc phosphate base and a permanent
restoration is placed. a: Permanent restoration; b: Pulp protecting base; c: Calcium hydroxide sub-base; d: Calcium hydroxide reacted affected
dentin; e: Calcification seen overlying the pulp horn
442 Short Textbook of Endodontics
– Excessive bleeding indicating hyperemia or pulpal • Can degrade and dissolve beneath restorations
inflammation • Tunnel defects: Calcium hydroxide fails to provide a long-
– Long standing pulp exposure that might have term seal against microleakage due to tunnel defects
contaminated with oral microorganisms. under the formed dentin bridge
• Rationale of direct pulp capping: The remaining dental • Calcium hydroxide is available as:
pulp with reversible pulpitis is selectively induced to – Two pastes (Base and catalyst)
produce a reparative barrier that protects the tissue from - Dycal
microbial challenges with the intention to postpone - Life
the more aggressive therapies, that could eventually - Care
lower the long-term prognosis for tooth retention and – Light cured system
function. • Properties:
“Teeth undergoing orthograde root canal therapy and – Mechanical: Low compressive strength
placement of posts and cores, followed by full coverage Low tensile strength
restorations, show lower long-term survival rates than Low elastic modulus limit
teeth with vital pulps.” (Ingle’s Endodontics, p. 1313) – Thermal: Calcium hydroxide provides some thermal
• Materials used: insulation if it is placed in sufficiently thick layers.
– Ideal requirements of a pulp capping material: But usually it serves only as a sub-base and needs to
- Adhere to dentin and overlying restorative be covered with a overlying base to provide thermal
material protection.
- Bactericidal or at least Bacteriostatic – Solubility of Ca(OH)2 in water is high
- Caries prevention: Should prevent secondary – Biological:
caries by releasing fluoride - Pulpal Repair: Alkaline pH (9.2–11.7) that causes
- Dentin formation: Should stimulate reparative irritation of pulp tissue stimulating pulpal
dentin formation defense and repair
- Easy to manipulate - Secondary/Reparative dentin formation: Pulpal
- Forces: Should be capable of resisting forces defense reaction and protein lysing effect results
during restoration placement and under in reparative dentin formation.
masticatory load It has been found that due to tunnel defects in dentinal
- Should provide a tight Seal against bacteria bridge associated with Ca(OH) 2, microorganisms can
- Should be Seen on radiographs (Radiopaque) penetrate pulpal tissue and cause subsequent pulpal
(Remember the ideal requirements using irritation. This is usually associated with pulpal calcification
Alphabetic formula ABCDEF S2). and canal obliteration.
– Pulp capping materials: Figures 27.3A to C are the diagrams showing steps
involved in direct pulp capping using calcium hydroxide.
A B C
D E F
Figs 27.4A to F Steps of two-visit direct pulp capping using MTA in a young permanent tooth. First visit: (A) Deep caries in permanent molar
tooth excavated, small (pin-point) exposure of pulp causing bleeding; (B) Cotton pellet moistened with 3–6% NaOCl is placed directly on
exposure site for 1–10 minutes; (C) MTA mixed to consistency of wet sand of about 1.5 mm thickness is gently patted down with moist cotton
pellet over the exposure site as well as on the surrounding dentin of pulpal roof or axial wall; (D) A moist cotton pellet is placed over MTA and
covered with an interim restoration. Second visit: (E) Interim restoration and cotton pellet removed and a probe is used to confirm that MTA
has set; (F) The tooth is permanently restored with composite restoration
Step 4: Place a lining of light cured GIC liner over MTA. • Rationale:
Step 5: Place bonded composite restoration in the same visit. Surgical excision of coronal pulp
Patient is recalled and checked after 3–6 months. ↓
Inflamed and infected area is removed
Pulpotomy
↓
• Definition: Pulpotomy is defined as “the surgical Leaving behind vital, uninfected pulpal tissue
removal of the coronal portion of a vital pulp as a means
in the root canal
of preserving the vitality of the remaining radicular
↓
portion” (Ingle’s Endodontics, p. 1312).
• Objectives: Remaining pulp may undergo repair while completing
– Preservation of vitality of radicular pulp apexogenesis (Root end development and calcification)
– Relief of pain in patients with acute pulpalgia in young permanent immature tooth.
– To promote apexogenesis in immature permanent (Also, removal of inflamed portion relieves pulpalgia.)
tooth ↓
Pulp Therapies 445
mechanical exposure cases. Coronal pulp up to the root adequate to achieve hemostasis. Various hemostatic and
canal orifices is extirpated, bleeding is controlled by pressure antimicrobial agents include:
and then a cotton pledget moistened with formocresol is • Ferric sulfate disinfectant (Consepsis-Ultradent
applied for about five minutes which is covered with zinc product)
oxide eugenol cement base and then restored with amalgam • Epinephrine
or glass ionomer restoration. Formocresol causes necrosis • Hydrogen peroxide
and fixation of tissue and is a potent antibacterial substance. • Sodium hypochlorite (NaOCl): It is safe and most
Steps involved in formocresol pulpotomy procedure in practical method to achieve hemostasis in vital pulp
a deciduous molar are demonstrated and explained in therapy. Besides excellent hemostasis, it removes
Chapter 28 Pediatric Endodontics. most of the dentinal chips as well as the biofilm and
thus brings about disinfection of the cavity interface.
Calcium Hydroxide Pulpotomy It also removes the damaged cells from mechanical or
traumatic exposure.
Calcium hydroxide has been widely used in vital pulp • MTAD (Mixture of Tetracycline isomer doxycycline,
therapy in permanent tooth due to its has antibacterial citric Acid and Detergent): MTAD has been tried and
property and ability to form hard tissue barrier. It has an favourable results achieved.
alkaline pH of 11. Coronal pulp is amputed to the level of
root canal orifices, hemorrhage is controlled and calcium WHAT IS THE CRITERIA FOR CASE SELECTION
hydroxide mixed with water or commercially available FOR VITAL PULP THERAPY?
paste containing calcium hydroxide in combination with • Age of patient: In case of young patients with initial caries
other medicaments is applied on the amputed pulp which on first molars causing reversible pulpitis, direct pulp
is covered with zinc oxide eugenol cement and then sealed capping can be done. Favorable prognosis for vital pulp
with a permanent restoration. Necrosis occurs under the therapy diminishes with increasing age of the patient.
placed calcium hydroxide, beyond which a reparative • Rate of decay: In case of patient with rampant caries,
dentinal bridge is formed. A radiograph is taken for future pulpotomy will be preferred over pulp capping as patient
comparison to check the calcific bridge formation after may have recurrent caries.
three months. A tooth treated with calcium hydroxide • Remaining tooth structure: If there is advanced caries
pulpotomy may develop internal resorption or calcification and severe coronal breakdown that may need full
of the root canal which also should be monitored on coverage restoration, pulpotomy rather than direct pulp
subsequent radiographs and Endodontic therapy should capping is recommended.
be performed as soon as apexogenesis is completed and is • History of restorative treatment: In case of mature
evident radiographically. permanent teeth, teeth with no previous history of
restorative treatment, direct pulp capping can be done.
Mineral Trioxide Aggregate Pulpotomy • Pulp hemorrhage: Visualize the pulp and assess the
hemorrhage. If bleeding can be controlled with 3–6%
Pulpotomy can be an effective procedure in deciduous teeth NaOCl applied with cotton pellet on exposed pulp
and young permanent teeth when MTA is used due to its for about 1–10 minutes, then direct pulp capping can
desirable properties mentioned before, such as alkaline pH be done. But if bleeding cannot be controlled, then
(10.2–12.5), antibacterial agent, pulp underneath has less diagnosis of irreversible pulpitis is made and pulpotomy
inflammation. It forms a dentinal bridge that is thicker and or pulpectomy may have to be done.
continuous unlike calcium hydroxide. MTA mix contains • Irreversible pulpitis in immature permanent tooth: In
calcium oxide which comes in contact with moisture to young permanent teeth with open apices, pulpectomy
form calcium hydroxide and induces the hard calcific bridge is done and MTA is used as a root end plug to promote
through the same mechanism as calcium hydroxide. root end closure.
WHAT ARE THE HEMOSTATIC AGENTS AND WHAT IS APEXIFICATION (NONVITAL PULP
ANTIMICROBIAL MATERIALS USED IN VITAL THERAPY)?
PULP THERAPY? Apexification
Direct pressure at the exposure site with cotton pellet • Definition: “Apexification is a method to induce
moistened in sterile water or saline may be sometimes development of the root apex of an immature, pulpless
Pulp Therapies 447
tooth by formation of osteocementum or other bone-like Histologically, the hard substance formed may have
tissue” (Grossman’s Endodontic Practice, 11th Edition, configuration either of bone, dentin, osteodentin or
p. 110). cementum
According to American Association of Endodontists, • Materials used: Calcium hydroxide, mineral trioxide aggre
“Apexification is a method to induce a calcific barrier gate (MTA), Radiopaque calcium hydroxide paste in a
in a root with an open apex or the continued apical methylcellulose base, calcium hydroxide in combination
development of an incomplete root in tooth with necrotic with Camphorated paramonochlorophenol, zinc oxide
pulp.” Apexification procedure involves debridement of paste, etc.
canal, short of the apex, without disturbing apical tissues • Technique:
and placement of a biocompatible material to stimulate – Using calcium hydroxide:
hard tissue formation. - Anesthesia may or may not be needed. Isolation
Open apex of an immature permanent tooth is also of tooth with rubber dam. Access preparation
called ‘blunderbuss apex’. and coronal pulp extirpation
Apexogenesis is the physiologic process of root - Preoperative radiograph used to determine
development whereas apexification is induced root end apparent length of the tooth and instrumentation
development using a biocompatible material. done 2 mm short of the apex to remove necrotic
• Objective: pulpal tissue and prepare the root canal for
– Induce closure of the open apical third of the root calcium hydroxide dressing.
canal - Root canal is dried with blunt absorbent points
– Formation of an apical barrier, creating an apical - Calcium hydroxide is mixed with sterile water
stop, against which obturation can be achieved. or anesthetic solution to a thick consistency
– Preserve and stimulate Hertwig’s epithelial root and carried to the pulp chamber using
sheath (HERS), to induce root end development by amalgam carrier with plastic tips and then
natural root lengthening process. thick, large finger plugger is used to force the
• Rationale: dry calcium hydroxide paste into the root canal.
– Any viable and undamaged apical pulp tissue present Alternatively, rotating lentulospiral can be used
in the root canal along with the odontoblastic layer to deliver the calcium hydroxide paste into the
associated with the pulp tissue is preserved root canal.
↓ - A radiograph is taken to confirm the correct
Cleaning and shaping/disinfection of the root canal placement of the medicament. Care should be
2 mm short of the radiographic apex to remove micro- taken to avoid pushing it beyond the apex.
organisms and toxic products without causing any - Temporary coronal seal: A dry cotton pellet
harm to the viable pulp tissue and HERS is placed over the material and sealed with
↓ reinforced zinc oxide eugenol cement.
Matrix formation and subsequent calcification guided - Recall: Patient is recalled after 3 months and
by viable HERS, creating an apical stop, against radiograph is taken to check if calcific barrier is
which dense obturation can be achieved. (Refer formed at or near apex. If it is not formed, then
Figure 27.6A) old calcium hydroxide dressing from the root
– If necrotic pulp and destroyed HERS, canal is removed using large files and copious
↓ irrigation with sterile water or normal saline to
Disinfection of root canal 2 mm short of root apex prevent irritation to periapical tissues. Patient
↓ is recalled every 3 months till radiographic
Biocompatible material used as chemical stimulant evidence of an apical barrier is seen that denotes
to induce differentiation of cementoblast or apexification. It has been found that this process
undifferentiated fibroblasts of periapical tissue and takes about 3 months to 21 months.
periodontal ligament - Once the apical stop is created, obturation of the
↓ canal with gutta-percha is done.
A hard substance forming a calcific bridge at or short Figure 27.7 shows the diagrammatic
of apex, creating an apical stop, against which dense representation of apexification procedure using
obturation can be achieved. (Refer Figure 27.6B) calcium hydroxide.
448 Short Textbook of Endodontics
A B
Figs 27.6A and B Successful outcome of apexification. (A) Root end
A B C
development; (B) Calcific bridge is formed
D E
Fig. 27.7 Apexification using calcium hydroxide Figs 27.8A to E Apexification procedure using MTA. (A) a: Necrosed
pulp, b: Open apex (blunderbuss); (B) Instrumentation done 2 mm
short of apex; (C) Apical plug of MTA and a moist cotton pellet is
placed in pulp chamber and sealed with a temporary cement. ‘a’
shows MTA apical plug; (D) Apical barrier formed is checked using
an Endodontic instrument such as plugger or spreader after 48 hours
– Using mineral trioxide aggregate: MTA is considered against which obturation is achieved; (E) Outcome after 3–6 months:
material of choice for apexification because it is a: Calcified bridge, b: Obturation of canal using gutta-percha, c:
Permanent restoration
found to create permanent apical plug at the outset
of treatment.
- Anesthesia may or may not be needed. Isolation - Mineral trioxide aggregate (MTA) is mixed with
of tooth with rubber dam. Access preparation distilled water as per manufacturer’s instructions
and coronal pulp extripation and placed as an apical plug in the apical 3–4 mm
- Preoperative radiograph used to determine using a special plugger or amalgam carrier.
apparent length of the tooth and instrumentation - Radiograph is taken to verify the placement
and irrigation done 2 mm short of the apex to - MTA sets under moisture. So, a moist cotton
remove necrotic pulpal tissue and to prepare the pellet is placed in the pulp chamber and access
root canal. is sealed using reinforced zinc oxide eugenol
- Root canal is dried with blunt absorbent points cement.
Pulp Therapies 449
A B
BIBLIOGRAPHY
Figs 27.9A and B (A) Radiograph showing immature pulpally
involved permanent maxillary right central incisor; (B) The case was 1. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis:
completed with an apical plug of MTA for apexification and gutta- Mosby, 2006.pp.834-82.
percha root canal filling in the same tooth (Courtesy of Dr Chetan 2. Grossman L, Oliet S, Del Rio C. Endodontic Practice, 11th edn.
Shah) Varghese publication, 1991.pp.102-15.
3. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics, 6th edn.
BC Decker Inc, Hamilton, 2008.pp.1310-29.
- After two days, hardening of MTA is checked 4. Reference Manual, V 36/No 6, 14/15, AAPD, ‘Guideline on Pulp
gently and obturation with gutta-percha is done. Therapy for Primary and Immature Permanent Teeth’.
28
CHAPTER
Pediatric Endodontics
This chapter explains the specific features of the Pediatric patients that may require special
considerations during Endodontic treatment and describes the various pulp therapies that can be
performed in Pediatric patients.
You must know
• What is Pediatric Endodontics?
• What are the Objectives of Preserving Primary Teeth?
• What are the General Features of Endodontic Treatment of Pediatric Patients?
• What are the Specific Morphologic Features of Teeth of Pediatric Patients?
• How to Establish a Correct Pulpal Diagnosis in Children?
• What is the Important thing you must know about the Proximal Lesions in Primary Teeth?
• Which are the Different Pulp Therapies Performed in Children?
• Pulp Therapies for Primary Teeth
WHAT IS PEDIATRIC ENDODONTICS? • Primary teeth have complex root canal anatomy.
• During Endodontic treatment of primary teeth, there is
Endodontic treatment performed in children for the danger of injury to permanent tooth bud.
preservation of primary and young permanent teeth with • There can be special problems associated with the
pulp involvement to prevent premature loss of primary natural resorption of primary tooth roots.
teeth and to facilitate completion of development of young
permanent teeth to render them functional for many years, WHAT ARE THE SPECIFIC MORPHOLOGIC
is called Pediatric Endodontics.
FEATURES OF TEETH OF PEDIATRIC PATIENTS?
WHAT ARE THE OBJECTIVES OF PRESERVING We shall discuss these features by classifying them in the
following way:
PRIMARY TEETH?
Objectives of preserving primary teeth include (Fig. 28.1).
Fig. 28.6 Maxillary first primary molar Fig. 28.9 Mandibular second primary molar
Clinical Examination
• Careful inspection and palpation of oral soft and hard
tissues.
Figure 28.10 shows multiple carious deciduous teeth
in a child. (Nursing bottle caries)
Figure 28.11 shows photograph of trauma to
permanent anterior teeth in a child.
• Intraoral sinus opening and draining sinus tracts are
quite common in children due to early involvement of
Fig. 28.8 Mandibular first primary molar pulp.
454 Short Textbook of Endodontics
Radiographic Examination
Fig. 28.10 Nursing bottle caries involving all maxillary teeth and
mandibular posterior teeth in a child (Courtesy of Dr Samir Khaire) Intraoral periapical (IOPA) and bitewing radiographs of the
affected area has to be taken.
On the radiograph:
• Extension of caries can be seen.
Figure 28.12 is radiograph showing pulpally involved
immature tooth with open apex.
• Physiologic root resorption of primary teeth may be
apparent.
• Developing permanent tooth buds are seen
• Calcified masses may be seen in pulp chamber in
response to irritation to pulp
• Radiolucency may be apparent in the bifurcation
or trifurcation of roots rather than at the apex due
to presence of accessory canals on pulpal floor or
communication from necrotic pulp to furcation through
altered dental tissue in area of furcation. Figure 28.13 is
radiograph showing radiolucency in the furcation and
around the roots of an over-retained deciduous molar.
Fig. 28.11 Trauma to permanent anterior teeth in a child • Pathologic root resorption and bone resorption may be
(Courtesy of Dr CR Suvarna) present due to extensive inflammation in the tooth.
• Internal root resorption due to pulpal pathosis may be
seen.
• Percussion test may not be very reliable because it • Follow-up of treatment: Radiographs of treated teeth are
depends on subjective response by the child. taken during the follow-up visits to evaluate the outcome
• Mobility test also may not be very reliable because of the of treatment. Figure 28.14 shows few examples of post-
aspect of normal physiologic mobility of primary teeth treatment and follow-up radiographs.
associated with natural resorption of roots.
A panoramic view is also very valuable radiograph
Pulpal Diagnostic Tests in Pedodontics as it shows in one view all the deciduous
teeth along with the permanent tooth buds so that proper
Thermal tests and electric pulp test are generally unreliable treatment can be planned. Figure 28.15 shows a panoramic
in children due to some aspects of pulpal anatomy of image of a patient.
primary teeth and due to other problems in children related After proper history taking and thorough clinical and
to apprehension and management. radiographic examination, or sometimes after direct
Pediatric Endodontics 455
Fig. 28.12 Radiograph showing pulpally involved Fig. 28.14 Few examples of post-treatment and follow-up
immature tooth with open apex (Courtesy of Dr Chetan Shah) radiographs (Courtesy of Dr Ashwin Jawdekar)
Dentin of primary teeth has wider tubules. As a result Another factor that needs to be considered is the
there is rapid progress of caries. There is possibility of dental age of the patient. If the dental age is more, then a
invasion of bacteria and their toxins much before frank conservative approach is preferred. If dental age is lesser,
carious exposure. then more definitive pulp therapies such as pulpotomy or
Moreover apart from stainless steel crown, it may pulpectomy needs to be done.
not be possible to seal the margins adequately. Thus a It is needless to state that proximal lesions will need
conservative approach in management of pulpal lesions adequate coronal seal and stainless steel restoration would
may not help. Therefore, pulp therapies such as indirect be the restoration of choice in most instances.
pulp capping or pulpotomy needs to be considered for all Figures 28.17A to C show the photographs and corres
deep proximal lesions. ponding radiographs of proximal lesions in various primary
teeth.
Pediatric Endodontics 457
C
Figs 28.17A to C Proximal lesions in primary teeth. (A) Maxillary posterior region;
(B) Mandibular posterior region; (C) Maxillary anterior region
WHICH ARE THE DIFFERENT PULP THERAPIES apices. The latter have been discussed in Chapter 27:
PERFORMED IN CHILDREN? Pulp Therapies and in Chapter 24: Management of Dental
In children, pulp therapies may be performed in primary Traumatic Injuries. Here we will discuss about the pulp
teeth or in young permanent teeth generally with open therapies for primary teeth.
458 Short Textbook of Endodontics
A C
B D
Figs 28.18A to D Steps of pulpotomy in primary teeth. (A) Caries involving coronal pulp in a mandibular first primary molar; (B) Excavation of
caries using a round bur; (C) Removal of the roof of the pulp chamber; (D) Amputation of coronal pulp to the level of orifices using a spoon
excavator
the pulp stumps. This cotton is left in contact carcinogenic potential and regarding its safe
with the pulp stumps for 5 minutes (Fig. use in dentistry.
28.18E). 2. Glutaraldehyde pulpotomy: 2–4% aqueous
■ A base of ZOE may be placed over stumps glutaraldehyde can be used for pulpotomy instead
■ The tooth is restored permanently (Fig. of formocresol.
28.18F). - Advantages of glutaraldehyde over formocresol:
Restoration can be composite resin in ■ Less cytotoxic than formocresol
anterior teeth and glass ionomer or amalgam ■ It has less systemic distribution after appli
or composite restoration followed by stainless cation and does not diffuse out of the apex of
steel crown for primary molars (Fig. 28.18G). the tooth. There is limited tissue binding and
- Safety: There are concerns about the systemic remainder of glutaraldehyde gets excreted in
distribution of formocresol and its likely urine or exhaled as carbon dioxide.
Pediatric Endodontics 461
E G
■ With glutaraldehyde, there is rapid fixation 3. Ferric sulfate pulpotomy: Ferric sulfate can also be
of the underlying pulpal tissue and the used to replace formocresol for pulpotomy and has
remaining radicular pulp maintains vitality been shown to give reasonably good clinical and
and is free of inflammation. radiographic results.
– Technique: Similar to formocresol pulpotomy 4. MTA pulpotomy: Formocresol can be replaced with
– Disadvantages: mineral trioxide aggregate for pulpotomy in primary
- Not as successful as formocresol pulpotomy teeth with good results.
- Limited shelf life.
462 Short Textbook of Endodontics
A B
C D
E (i) E (ii)
Figs 28.19A to E Steps of pulpotomy. (A) Mandibular second primary molar is isolated using rubber dam after adequate anesthesia;
(B) Caries is excavated completely; (C) Deroofing the pulp chamber; (D) Coronal pulp is removed and hemostasis is achieved; (E) Pulpotomy
agent is placed and the tooth is restored with a temporary cement: (i) Photograph showing good temporary seal achieved after pulpotomy:
(ii) Postoperative radiograph of the same case in which pulpotomy was performed for mandibular second primary molar and pulpectomy was
performed for mandibular first primary molar (Courtesy of Dr Ashwin Jawdekar)
Pediatric Endodontics 463
Pulpectomy
A
It involves extirpation of pulp from both coronal and
radicular spaces, cleaning and shaping of canals and
obturation with a resorbable root filling material.
• Indications:
– Irreversible pulpitis
– Necrotic pulp
• Contraindications:
– Tooth close to exfoliation having moderate to
excessive mobility
– Nonrestorable tooth with only carious root piece
or stump remaining. In such cases, extraction of
primary tooth followed by space maintainer would
be preferred.
• Objectives:
– Following pulpectomy treatment, radiographic
radiolucency suggestive of infectious process should
resolve in six months.
– Pretreatment clinical signs and symptoms should
resolve in few weeks.
– Optimum root canal filling evidenced on radiograph B
with no gross overextension or underfilling
Figs 28.20A and B Steps of pulpectomy in primary teeth. (A) Mandi
– Treatment should permit physiologic resorption of bular first primary molar with extensive caries involving the pulp;
primary tooth and filling material to allow for normal (B) Excavation of caries and access cavity preparation
eruption of succedaneous tooth
– No pathologic resorption or furcation/apical
radiolucency
• Technique: Figures 28.20A to F show the steps of – Access cavity preparation is done by connecting all
pulpectomy in a primary molar tooth: the pulp horns.
– Anesthesia and rubber dam isolation. Access preparation is made through the lingual
– Removal of caries. Figure 28.20A shows deep caries surface for the anterior primary teeth and through
in mandibular primary molar involving the pulp. the occlusal surface for the primary molar teeth.
Figure 28.20B shows excavation of caries and access – Removal of roof of pulp chamber followed by entire
cavity preparation. coronal pulp to the level of orifices.
464 Short Textbook of Endodontics
C D
Figs 28.20C and D (C) Extirpation of pulp and cleaning and shaping of root canals: Circumferential filing with K-files in sequence to a
predetermined length estimated from a preoperative radiograph; (D) After thorough debridement, the canals are filled with zinc oxide
eugenol (Obturation)
– Flaring of access preparation walls for easy insertion – Irrigation of canals and then dry the canals with
of files and to achieve straight line access to the apical sterile paper points.
portion of the canals. – Then, obturation of canals with a suitable obturation
– From preoperative radiograph, determine the material (Fig. 28.20D).
approximate length of roots and then measure the • Ideal requirements of obturation material for primary
Endodontic instruments such as K-files about 1 mm teeth:
short of the apex. – Biocompatible
– Barbed broach or the smaller files can be inserted – Antiseptic
in the canals to this length for pulp extirpation (Fig. – Resorbable—at par with tooth
28.20C). – Good handling
– Copious irrigation with sodium hypochlorite 3% or – Economical
sterile saline should be done. – Radiopaque
– Cleaning and shaping: Circumferential filing with • Materials used for obturation of root canals of primary
2–3 K-files or H-files in sequence of size to the length, teeth (Table 28.1):
should be done. Excessive enlargement of canals – Zinc oxide eugenol: Zinc oxide eugenol is
may cause unnecessary damage to tooth such as biocompatible, antiseptic and has good handling
perforation and hence should be avoided. Stainless properties. It is economical and is a time-tested
steel or nickel-titanium (Ni-Ti) instruments can be material. It has been used as an obturation material
used. Ni-Ti instruments are recommended due to for primary teeth since many years. The limitation
their flexibility. Both hand and rotary instruments of ZOE is that it resorbs very slowly. Its resorption is
can be used. If stainless steel instruments are used, not par with resorption of roots of primary teeth.
the instruments need to be gently curved to help – C a l c i u m h y d r o x i d e : C a l c i u m h y d r o x i d e
negotiate the canals. is biocompatible and has excellent antiseptic
The objective of cleaning and shaping in primary properties. But its antiseptic action is short-lived.
teeth is to remove the pulp tissue and debris from Within few days, its pH becomes neutral and
the canals and make space for a resorbable root becomes ineffective. It rapidly resorbs from the root
filling material. canal. Although, it is a good material to be used for
Pediatric Endodontics 465
• In case of primary canines and molars with necrotic pulp – Pressure syringe: Commercially available filling
and abscess, if nonsetting obturation material is used, devices are available such as Navitip, Vitapex syringe,
there is high possibility that it will get resorbed easily. etc
So, a hardsetting material is preferred such as calcium – Syringe with needle
hydroxide with iodoform-hard setting (Endoflas). – Wet cotton: The pulp chamber is filled with the
Alternatively, in such cases, calcium hydroxide dressing obturating material such as ZOE and a wet cotton
can be given for one week and then ZOE can be used as pellet is pressed over it few times so that it flows into
obturation material when the canals are dry. the canals.
• In case of primary canines and molars which had a – Lentulospiral: Endodontic hard instruments such
vital pulp, any of the obturation material: ZOE, calcium as files or rotary lentulospiral fillers can be used.
hydroxide and iodoform combination—nonsetting or Important thing to note in case of filling using
hard-setting, can be used. lentulospiral fillers is that it should be inserted
• Obturation techniques in primary teeth: and removed from the canal while in rotation. The
– Incremental: The canals can be coated with the paste rotation should not be started or stopped when in
of unreinforced ZOE using paper points, k-files or the canal for its effective use otherwise the ZOE gets
spreader incrementally. removed with the lentulospiral filler.
A B
Figs 28.21A and B Stainless steel crowns placed on Endodontically treated deciduous and permanent molars
(Courtesy of Dr Ashwin Jawdekar)
A B C
Figs 28.22A to C Radiographs of a pulpally involved primary molar in which pulpectomy was performed. (A) Preoperative radiograph;
(B) Intraoperative radiograph with K-files inserted in the canals for determination of working length; (C) Postoperative radiograph
Pediatric Endodontics 467
- Radiograph can then be taken to confirm if the Figures 28.22A to C show the radiographs of primary
canals have been adequately filled. mandibular second molar tooth (Pre-intra- and post-
- After obturation with zinc oxide eugenol, operative views).
permanent restoration such as glass ionomer or
silver amalgam is placed in the pulp chamber BIBLIOGRAPHY
space (Fig. 28.20E) 1. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis:
- Tooth should be restored with stainless steel Mosby, 2006.pp.822-74.
crown (Figs 28.20F and 28.21A and B) 2. Dr Ashwin Jawdekar, Little Smiles Child Care Pvt. Ltd.,
Presentations and Notes.
- In case if the succedaneous permanent tooth
3. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics, 6th edn.
is missing and the retained primary tooth is BC Decker Inc, Hamilton, 2008.pp.1400-25.
pulpally involved, the canals can be filled with 4. Reference Manual, V 36/No 6, 14/15, AAPD. Guideline on Pulp
gutta-percha after pulpectomy. Therapy for Primary and Immature Permanent Teeth.
29
CHAPTER
Geriatric Endodontics
This chapter describes the Endodontic treatment for the geriatric patients and explains the specific
features of the older patients that may require special considerations.
You must know
• What is Geriatric Endodontics?
• What is the Scope of Geriatric Endodontics?
• What is the Need for Geriatric Endodontics?
• What are the Specific Features of General Health of Older Patients?
• What are the Regressive Changes that occur in the Teeth with Increasing Age?
• What are the Specific Features of Teeth of Older Patients?
• Which Orofacial and Dental Signs and Symptoms are Elicited by Clinician to Derive Correct
Diagnosis?
• What are the Different Diagnostic Tests?
• How to Formulate Treatment Plan after making Correct Diagnosis in Geriatric Patient?
• What are the Steps in Endodontic Treatment in Geriatric Patient?
• The most difficult step in Endodontic treatment of older Obturation of Root Canal System
patients is adequate access and identification of root
canal orifices. This may be due to thin, small geriatric • For older patients, excessive pressure during obturation
canals, which may be calcified most of the times that can result in root fracture. So, the obturation techniques
makes location and penetration of canal orifice quite that do not require unusually large mid-root tapers and
difficult and time-consuming. do not generate pressure in this area are selected.
• Remove caries and existing restorations if any, under • Obturation using a thermoplasticized material such as
suitable magnification in the form of loupes or resilon, can significantly reduce coronal leakage that
microscopes. can result from root caries after Endodontic treatment
• Location and initial penetration of the canal orifice with and also it increases resistance to root fracture.
DG-16 explorer. • Permanent restorative procedures should be scheduled
Canal negotiation with #8 k-file with gentle apical as soon as possible to prevent coronal leakage.
pressure and prelubricated with a chelating agent.
• If risk of deviation from long axis exists such as in heavily Post-Endodontic Restoration
restored tooth or calcified canals, surgical access may be
preferred. • Root fracture is common in older adults when posts with
• Errors: much taper is used.
– Canals may be overlooked. Careful location of • Post fracture or failure may occur when small diameter
orifices is important. parallel post is used.
– Perforation: Pain, bleeding, disorientation of probing • In older patients, factors determining type of restoration
instrument may indicate perforation. include root caries, cervical erosion, gingival recession,
bone loss and lesser number of teeth remaining.
Cleaning and Shaping (Biomechanical • In case of older patients, often multiple teeth are missing.
So there may be insufficient vertical and horizontal
Preparation)
space when opposing or adjacent teeth are missing.
• Reparative dentin deposition and calcification makes
penetration of canals difficult Repair after Endodontic Treatment
• Due to constant deposition of cementum throughout
life, length of canal from actual anatomic foramen to • Repair may be delayed due to age-related changes such
CDJ increases, but actual CDJ width remains constant as:
with age. – Increase in atherosclerotic changes of blood vessels
• Usually crown-down technique is followed: Flaring of – Viscosity of connective tissue is altered
coronal 1/3rd of canal to provide a reservoir of irrigating – Decrease in rate of bone formation and normal
solution and reduce the stress on metal instruments. resorption
• Thorough copious irrigation with sodium hypochlorite – Greater porosity of bone
to remove debris that block access. – Decreased mineralization of formed bone
• Instruments with no rake angle are beneficial. • In case of vital pulps with normal periapical tissue: Good
• Canal preparation should terminate at CDJ (narrowest prognosis of Endodontic therapy and periapical tissue
constriction of canal): 0.5 to 2.5 mm from radiographic can be maintained normal by confining preparation and
apex. filling procedures to canal space.
Geriatric Endodontics 473
• In case of infected nonvital pulps with periapical Considerations for Endodontic Surgery
pathologic abnormalities: Repair is determined by
Medical Local
ability of host tissue to respond.
Thorough evaluation of Medical • Presence of fenestrated or dehisced
history is done. Some special roots and exostoses
Endodontic Surgery in Geriatric Patients considerations may be needed: • Thickness of overlying soft and
• Prophylactic antibiotic bony tissue.
Endodontic surgery may be considered in geriatric patients premedication • Relationship of anatomic
if the case is definitive indication for surgery, but may • Sedation structures such as sinus, floor
• Hospitalization of nose, neurovascular bundle
require medical consultation. • More detailed evaluation with surrounding structures may
change when teeth are lost.
Need for Endodontic Surgery • If root end surgery is to be
Surgical access may be preferred in case of anatomic performed, consider whether
the root that will be left is long
complications of RC system such as small or completely enough and thick enough for
calcified canal, non-negotiable root curvatures, extensive tooth to remain functional and
apical root resorption or pulp stones. stable after surgery.
Perforation during access, losing length during
instrum entation, ledging and instrument separation
are iatrogenic treatment complications associated with BIBLIOGRAPHY
treatment of calcified canals. Hence, surgical Endodontics 1. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis:
may be considered. Mosby, 2006.pp.883-915.
30
CHAPTER
Pathologic Tooth
Resorption
This chapter explains in detail about tooth resorption and its different types.
You must know
• What is Tooth Resorption?
• What is Mechanism of Tooth Resorption?
• What are the Etiologic and Stimulating Factors of Tooth Resorption?
• Which are the Types of Tooth Resorption?
• Which are the Clinical and Radiographic Features of Different Types of Tooth Resorption and
How to Manage them?
• What are the Differences between External and Internal Root Resorption?
WHICH ARE THE CLINICAL AND RADIOGRAPHIC Fig. 30.1 External root resorption
FEATURES OF DIFFERENT TYPES OF TOOTH
RESORPTION AND HOW TO MANAGE THEM? Figure 30.1 shows diagrammatic representation of
External Root Resorption External root resorption.
• Etiology and pathogenesis:
Definition: “External resorption is a lytic process occurring – Acute repair-related resorption may occur in case of:
in cementum or cementum and dentin of the roots of the - Dental traumatic injuries: Luxation injuries
teeth.” (Grossman’s Endodontic Practice, 11th edn, Pg. 98). (Concussion, subluxation and lateral luxation)
It is resorption that occurs on the external or lateral and following Intrusion
surface of the root. - Replantation of avulsed teeth.
Injury may be only to the external root surface with - Root fracture: Here it may be found adjacent to
no inflammation in root canal. But, sometimes injury to the fracture line.
external root surface is associated with an inflammatory – Chronic injury: Associated with orthodontic
stimulus in root canal. In such cases, there are chances of treatment, traumatic occlusion, pressure from cysts
pulp necrosis causing pulp space infection. or tumors and ectopically erupted teeth.
When the trauma and/or pressure is discontinued,
Types of External Root Resorption spontaneous healing tends to occur. This is a typical
feature of repair-related resorption. The injured
1. External surface resorption (repair-related resorption): tissue is removed by osteoclast and macrophages
It represents the healing response to chronic and/or in about 2–4 weeks, following which repair occurs
acute injury in the PDL that affects the cells adjacent to by progenitor cells from adjacent PDL.
the root surface. • Clinical features: No significant signs or symptoms.
Pathologic Tooth Resorption 477
molars, replacement resorption starts in intraradicular • Coronal portion of tooth may be necrotic.
area and gradually spread to remaining part of the root. • Pulp in the apical portion that includes the internal
• Treatment: Endodontic treatment should not be done as it resorptive defect may be vital.
aggravates the aggressive nature of ankylosis process. In • After a period of active resorption, tooth may become
case of primary dentition, decoronation treatment in early nonvital.
stages. If it is diagnosed late (during adolescence) then it
should be rebuild to prevent supraeruption of antagonistic • Diagnosis
tooth. In permanent dentition, if diagnosed early, – ‘Pink spot’ appearance of crown in later stages of
extraction of involved tooth. If diagnosed later, then rebuild resorption when integrity of crown is compromised.
the tooth to prevent supraeruption of the antagonist tooth. – Later stages may be associated with perforations.
– On radiographic examination:
Internal Root Resorption - Round or ovoid uniform radiolucent enlargement
“Internal resorption is an idiopathic slow or fast progressive of the pulp canal may be seen Figure 30.4 shows
resorptive process occurring in the dentin of the pulp
chamber or root canals of teeth”.
• It represents progressive pulp healing.
• It begins centrally within the tooth, initiated by
inflammation of the pulp.
• It is less common than external root resorption in
permanent teeth
• An oval-shaped enlargement of root canal space is seen
in internal root resorption.
• The multinucleated giant cells adjacent to granulation
tissue in the pulp cause the resorption of internal aspect
of the root.
Figure 30.2 shows diagrammatic representation of
internal root resorption.
Clinical Features
• Usually asymptomatic. Pain may be a symptom if
perforation of crown occurs.
Thus, two types of internal root resorption:
1. Nonperforating (asymptomatic)
2. Perforating (painful)
• Maxillary anterior tooth is found to be commonly
affected.
• Reddish area showing through the resorbed area of
the crown representing the granulation tissue is the
pathognomonic sign of internal resorption (Figure 30.3
shows reddish-pink discoloration in maxillary right
central incisor suggestive of internal resorption. Also Fig. 30.3 Internal resorption in maxillary right central incisor (pink
referred to as “pink tooth”). tooth) (Courtesy of Dr Manoj Ramugade)
Pathologic Tooth Resorption 479
Fig. 30.4 Radiograph showing internal resorption in maxillary left Fig. 30.5 CBCT scan image of a tooth with internal resorption. Note
central incisor tooth which has perforated the root (perforating the oval-shaped enlargement of root canal space (Courtesy of Dr
internal resorption) Mansi Shah, Dentoview-Advanced dental imaging center)
3. Internal replacement resorption (metaplastic resorp Class IV: Resorptive defect extending beyond the coronal
tion): third of the root.
– Etiology and pathogenesis: Related to trauma • Clinical features: Initially, the cervical invasive resorption
mainly. Other causes include: extreme heat to tooth, is asymptomatic. Long-standing cervical resorption
pulpotomy procedures, etc. causes loss of tooth structure replaced by granulation
Damaged pulp tissue is replaced as a part of tissue, which undermines the enamel. So, a “pink spot”
healing process with an in growth of new tissue next to the cervical margin is seen in expansive lesions. It
which includes bone-derived cells. Root is gradually should be differentiated from the pink tooth appearance
replaced by bone. The postnatal pulp stem cells of internal resorption, by radiographic examination.
which are present in the apical part of root canal are • Radiographic features: Appears as cervical bowl-shaped
the source for the metaplastic hard tissue formed in lesion that progresses in coronal and apical directions.
replacement resorption as reparative response to In initial phases, the root canal is not involved. As the
restorative result. resorption progresses, the root canal gets involved.
– Clinical features: Most of the times asymptomatic. • Treatment: Raise a surgical flap, remove granulation
If ankylosis occurs, tooth will gradually develop tissue and place a dentin-bonded restoration. If
infraocclusion. pulp canal gets involved then Endodontic treatment.
– Radiographic features: Radiographically, it appears After Endodontic treatment, the resorbed area may
as a dissecting resorptive area in the center of root be repaired from an internal or external approach.
canal. Root canal space may appear engorged with Intentional replantation and root amputation are the
radiopaque material suggestive of hard tissue. other treatment options in such cases.
– Treatment: Endodontic treatment, although it may Figure 30.6 gives the mind-map to remember the
have poor prognosis due to lack of root maturity. different types of pathologic tooth resorption.
Fig. 30.6 Mind-map to remember the different types of pathologic tooth resorption
BIBLIOGRAPHY
1. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis: 3. Zvi Fuss, Igor Tsesis, Shaul Lin. “Root Resorption-Diagnosis,
Mosby, 2006.pp.630-9. Classification and Treatment Choices based on Stimulation
2. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics, 6th edn. Factors”, Dental Traumatology. Blackwell Munksgaard.
BC Decker Inc, Hamilton, 2008.pp.1358-80. 2003;19:175-82.
31
CHAPTER
Dentinal Hypersensitivity
and its Management
This chapter explains in detail about dentinal hypersensitivity with respect to its etiology, diagnosis
and different treatment modalities for its management.
You must know
• What is Dentinal Hypersensitivity?
• What are the Different Hypotheses put Forward to Explain the Mechanism of Dentinal
Hypersensitivity?
• What is the Incidence and Prevalence of Dentinal Hypersensitivity?
• What are the Predisposing Factors that cause Dentinal Hypersensitivity?
• How to Diagnose Dentinal Hypersensitivity?
• How to Manage Dentinal Hypersensitivity?
WHAT IS THE INCIDENCE AND PREVALENCE OF • Erosion from dietary or gastric acids (Chemical- Erosion)
DENTINAL HYPERSENSITIVITY? • Occlusal stresses
• Periodontal patients with gingival recession and
Incidence and prevalence of Dentinal Hypersensitivity: exposed root surfaces: Periodontal disease causes
• More common in females than males. recession of gingiva. Gingival recession exposes
• In cervical region of incisors and premolars, often on cementum to the oral environment. The thin layer of
the side opposite the dominant hand. cementum is lost by toothbrushing or flossing or using
• Toothbrush abrasion being the most common cause. tooth picks and dentin gets exposed which may respond
• Occurs mostly in third to fourth decades of life. to stimuli.
• Decline in prevalence of hypersensitivity in older • May be increased following Scaling and Root
patients due to decrease in dentinal tubule permeability. planning.
• More with cold stimuli (90%) than other stimuli such as • Dehydration/Dessication of dentinal surface by airblast.
chemical (Candy) or mechanical (toothbrushing). • Acid etching of exposed dentin to remove the smear
• Commonly involved areas: Cervical areas of teeth layer opens the tubule orifices and makes dentin more
are commonly affected by Dentinal Hypersensitivity. responsive to stimuli such as air blasts and probing.
Facial root surfaces in canines, premolars and molars
are particularly affected, especially in the areas of HOW TO DIAGNOSE DENTINAL
periodontal attachment loss due to their susceptibility to
HYPERSENSITIVITY?
toothbrush abrasion often on opposite side of dominant
hand. Diagnosis of dentinal hypersensitivity is based on eliciting:
• Type of stimuli
WHAT ARE THE PREDISPOSING FACTORS THAT • Duration of pain
• Location
CAUSE DENTINAL HYPERSENSITIVITY?
• Absence of pulpal symptoms
• Movement of fluid in the dentinal tubules is the basic • Absence of radiographic changes.
event in the arousal of pain. Dentin Sensitivity is not a problem in intact teeth. It is
• Dentin may be hypersensitive due to possible to activate neurons with high intensity stimulus
– Lack of protection by Cementum or Enamel during cold testing (vitality test for pulp) with ethyl chloride
– Loss of smear layer spray. It represents normal dentinal sensitivity. When the
– Hydrodynamic movement of fluids in dentinal tooth feels more sensitive than the normal, it is called
tubules. Dentinal Hypersensitivity.
• Pain is amplified when dentinal tubules are open to oral Pain is evoked by cold stimuli, mechanical stimuli
cavity. (probing with an explorer tip), and hypertonic stimuli
• Patent dentinal tubules are usually present in areas of (sweets). Pain is short, sharp pain in response to
hypersensitivity and may result in increased irritation stimuli arising from exposed dentin. Pain is of mild to
and localized reversible inflammation of the pulp at moderate intensity and patient usually is able to localize
the sites involved. When the patent dentinal tubules are the tooth.
exposed, ‘A’ fibers innervating the dentinal tubules or Symptoms of dentinal hypersensitivity are reversible.
located in pulp adjacent to dentinal tubules get activated
by stimuli such as blast of air from air/water syringe, HOW TO MANAGE DENTINAL
scratching the dentin with explorer tip, rapid cooling,
HYPERSENSITIVITY?
or presence of hypertonic solution (sweets).
• Thus, Dentinal hypersensitivity may be caused by: Newly exposed dentin may be very sensitive. However,
– Inflammatory changes in the pulp or within a few weeks, sensitivity subsides due to:
– Mechanical changes in the patency of dentinal • Gradual occlusion of the tubules by mineral deposits,
tubules. thus reducing the hydrodynamic forces.
• Deposition of reparative dentin over the pulpal ends of
Dentinal hypersensitivity may be related to: the exposed tubules.
• Excessive abrasion caused due to vigorous tooth • Formation of smear layer from tooth brushing or
brushing (Mechanical-Abrasion) dentinal sclerosis.
Dentinal Hypersensitivity and its Management 485
Thus in few cases, Dentinal Hypersensitivity resolves – 5% potassium nitrate: Potassium reduces the
without treatment. In other cases that do not spontaneously neuronal activity, thus decreasing the dentinal
desensitize, need treatment. hypersensitivity. Studies have shown that the
potassium containing dentrifices reduce the
Management of Dentinal Hypersensitivity hypersensitivity to cold by about 60%.
– 10% strontium chloride: Strontium chloride acts by
• Identify the cause or the predisposing condition causing blocking the dentinal tubules. Studies have found
dentinal hypersensitivity. it to be effective by 50–70% in reducing dentinal
– If the exposed dentin is due to vigorous tooth hypersensitivity.
brushing habit, patient should be educated regarding – Fluoride in the form of Sodium Monofluoro-
the right brushing technique, use of soft toothbrush, phosphates has also been found to be quite effective
etc. in the management of dentinal hypersensitivity.
– If dentin is exposed due to erosion by gastric acids, • Following treatment modalities can be used in the
then its medical treatment is advised to prevent management of dentinal hypersensitivity.
further erosion of enamel. Dietary counselling may – Burnishing of the exposed root surface to form smear
help in these cases. It has been found that there is layer using an orange wood stick or toothpick. This
greater loss of dentin when brushing is performed occludes the open dentinal tubules to some extent
immediately after exposure of tooth surface to and reduces dentinal hypersensitivity.
dietary acids from citrus fruits. Patients should be – Application of desensitizing agents:
informed and cautioned regarding this. - Desensitizing agents that form insoluble
– If traumatic occlusion is the cause, then it should be precipitates within the dentinal tubules—Certain
corrected. soluble salts react with ions in tooth structure and
– If periodontal condition causing gingival recession form crystals on the surface of dentin. Examples
and exposed root surfaces is the problem, then of such agents include: Oxalate compounds.
periodontal therapy along with the treatment of Oxalate ion reacts with calcium ions in dentin
dentinal hypersensitivity. fluid causing precipitation of calcium oxalate
– If recent Scaling and root planning (Periodontal in the dentinal tubule. This causes decrease
therapy) has resulted in hypersensitivity, patient in functional diameter, thereby limiting fluid
should be reassured that it will resolve in few days movement. Potassium ion can reduce nerve
without any treatment or some therapeutic agent activity. Commercially available potassium
may be used for its treatment. oxalate solutions to treat sensitive dentin can be
– If hypersensitivity is related to recently done used.
Composite restoration in which acid-etching was - Desensitizing agents that occlude the dentinal
done (total-etch technique), patient should be tubules with precipitated plasma proteins in dentinal
reassured that mild postoperative sensitivity will fluid. For example, Hydroxyethyl methacrylate
gradually subside, but clinician should also check (HEMA) with or without Glutaraldehyde.
for occlusal high points in the restoration and other Various therapeutic agents for dentinal hyper
causes of postoperative sensitivity with composites sensitivity can also be classified as:
(such as over-drying of dentin, over-etching, faulty a. Neural-modulating agents: E.g. Potassium nitrate.
technique, moisture contamination, etc.) In few b. Tubule-blocking agents: E.g. Strontium chloride,
cases, removal of the restoration and re-doing it with oxalates.
correct technique and using Self-etch technique will – Application of dentin bonding agents: Dentin
solve the problem. bonding agents and dentin adhesives reduce
• Prescribing home-use desensitizing dentrifices and sensitivity by forming resin tags and a hybrid layer.
mouthwashes: Use of Desensitizing dentrifices and For example, Primer of the original Gluma adhesive
mouthwashes by the patient for few weeks to months system (an aqueous solution of 5% Glutaraldehyde,
can provide relief from dentinal hypersensitivity. This 35% HEMA) marketed as GLUMA desensitizer. It
is specially in cases of Generalized attrition or multiple reduces sensitivity by protein denaturation process
teeth with mild abrasion. with concomitant changes in dentin permeability. It
Desensitizing dentrifices and mouthwashes may has been found to be quite effective in management
contain the following agents. of dentinal hypersensitivity.
486
Short Textbook of Endodontics
TABLE 31.1 Management of dental hypersensitivity TABLE 31.2 Management of dentinal hypersensitivity (According
to Hargreaves and Seltzer, Seltzer and Bender’s Dental Pulp, 2002
1. Identify the cause or predisposing condition and take measures to edn.)
correct it.
2. Home-use dentrifices and mouthwashes: Interventions that reduce dentinal Interventions that reduce the activity of
• 5% potassium nitrate permeability and block dentinal dentinal neurons
• 10% strontium chloride fluid flow
• Fluoride sodium monophosphate Application of materials such as: Application of:
3. Treatment modalities: 1. GLUMA dentin bond 1. Potassium containing dentrifices
• Burnishing of exposed root surface
• Application of desensitizing agents: 2. Oxalate salts 2. 10% strontium chloride
– That form insoluble precipitates within dentinal tubules 3. Isobutyl cyanoacrylate 3. Fluoride containing medicaments
(oxalate compounds)
4. Fluoride-releasing resins or 4. Guanethidine 1% solution
– That occlude dentinal tubules with precipitated plasma proteins
varnishes
in dentinal fluid (HEMA with or without glutaraldehyde)
Therapeutic agents: 5. CO2 lasers
– Neural-modulating agents, e.g. potassium nitrate 6. Coronally positioned
– Tubule-blocking agents, e.g. Strontium chloride, oxalates mucogingival flaps
• Application of dentin bonding agents: Gluma (5% glutaraldehyde
35% HEMA)
• Composite resin restorations
• Lasers:
– Low-output: GaAlAs conducted and current available evidence does not
– High-output: Nd:YAG support the use of lasers for treatment of dentinal
hypersensitivity. So, other more conservative and
economical treatment modalities are recommended.
– Composite resin restoration: Cervical abrasion or Management of Dentinal Hypersensitivity has been
erosion (Class V cavity) can be treated by restoring summarized in Table 31.1.
with composite resin restoration. Newer self-etch Therapies for management of dentinal hypersensitivity
systems are preferred. The open dentinal tubules are can also be classified as shown in Table 31.2 (According to
thus sealed preventing pain producing stimuli from Seltzer and Bender).
reaching the pulp. A mind-map to remember all points of dental
– Us e of las ers in manag ement of dentinal hypersensitivity is given in Figure 31.2.
hypersensitivity: Lasers such as Nd:YAG, CO2 lasers
and others have been tried in the treatment of BIBLIOGRAPHY
dentinal hypersensitivity. Low-output lasers such
1. Bhaskar SN. Orban’s Oral histology and embryology, 11th edn.
as GaAlAs have been found effective in mild to Mosby; 2001.p.123.
moderate cases of dentinal hypersensitivity. They 2. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis:
are thought to cause a transient reduction in action Mosby; 2006.pp.35, 49-50, 487-90, 520-521, 531.
potential mediated by pulpal C fibers but not 3. Hargreaves KM, Goodis HE. Seltzer and Bender’s Dental Pulp,
A-delta fibers. High-output lasers such as Nd:YAG Quintessence Books; 2002.pp.205-11.
4. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics 6, 6th edn.
have been found to cause superficial occlusion BC Decker Inc, Hamilton; 2008.pp.386-7.
of dentinal tubules in addition to action potential 5. Theodore MR, Herald OH, Edward JS. Sturdevant’s Art and Science
blockage within the pulp. However, the clinical trials of Operative Dentistry, 5th edn. Elsevier, Mosby; 2006.pp.268-9.
32
CHAPTER
Lasers in Endodontics
This chapter describes a few aspects of Laser Physics and explains the clinical applications of lasers
in Endodontics.
You must know
• What is Laser?
• What are the Properties of Lasers?
• What are the Components of Lasers?
• What are the Modes of Laser Light Emission?
• How is the Laser Interaction with Biologic Tissues?
• Which are the Type of Lasers?
• What are the Applications of Lasers in Endodontics?
• What are the Advantages and Limitations of using Lasers in Endodontics?
– It has high thermal absorption. So, they are not • Pulp capping
suitable for drilling or cutting enamel and dentin as – Nd:YAG, CO2, Argon and Er:YAG lasers can be used
damage to dental pulp may occur. for pulp capping procedures.
• Er:YAG laser (2.94 microns) • Pulpotomy
– It is most efficient for drilling and cutting enamel – FDA has approved the diode laser as an adjunct for
and dentin. removal of pulp tissue in pulpotomy procedure.
– Its energy is well-absorbed by water and – Nd:YAG and Argon lasers can be used.
hydroxyapatite. • Root canal preparation (Shaping)
• Nd:YAG laser (1.06 microns) – Lasers can be used to remove dental pulp and
– Nd:YAG photons are transmitted through tissues by organic debris from the root canal.
water. – Lasers modify the dentinal walls by inducing melting
– They interact well with dark pigmented tissue. and resolidification cycles that cause enlargement of
– Nd:YAG laser is effective for disinfection of the root the root canal walls.
canal and soft tissue procedures. • Disinfection of root canals
– It can be used to treat dentinal hypersensitivity. – The potential bactericidal effect of laser irradiation
• Argon lasers (488 or 514 nm) can be effectively utilized in cleaning and disinfection
– It has two wavelengths—Blue and Green. Blue of the root canal system following biomechanical
wavelength (488 nm) is used mainly for curing of instrumentation.
Composite Restorations, Green wavelength (514 – For disinfection of the root canals, laser energy can be
nm) is mainly used for soft tissue procedures and used directly or in combination with a photosensitive
coagulation. chemical, which is activated by low energy laser light
– They are more effective on pigmented or highly to kill the microorganisms (Photodynamic therapy)
vascular tissues that aid in distributing the disinfecting solutions
– Delivered through fiberoptic. more effectively in the root canal system (Photon-
• Excimer lasers Induced-Photoacoustic-Streaming (PIPS).
- They function by breaking molecular bonds and – Pulsed low energy laser emanates propagation of
reducing the tissue to its anatomic constituents acoustic waves
before dissipating the energy as heat. – Studies have shown that Nd:YAG, Argon, Er, Cr:YAG
Nd:YAG, Argon and Excimer lasers can be delivered and Er:YAG laser irradiation has the ability to remove
through fiberoptic that provides greater accessibility to debris and smear layer from the root canal walls
different areas and structures in oral cavity. following biomechanical instrumentation.
– Emitted energy is delivered into the root canal system
WHAT ARE THE APPLICATIONS OF LASERS IN by
a. A thin optical fiber (Nd:YAG, KTP-Nd:YAG,
ENDODONTICS?
Er:YSGG, argon and diode)
• Pulpal diagnosis b. A hollow tube (CO2 and Er:YAG)
– Laser Doppler Flowmetry (LDF) is used to assess – The delivery of laser through a flexible optical fiber
blood flow in microvascular system. of 200 microns for canal decontamination has shown
– It can be used to measure blood flow in the dental positive results.
pulp. – The properties of laser light may allow a bactericidal
– Nd:YAG laser is applied for thermal testing (heat effect beyond 1 mm of dentin.
test) – Limitations of intracanal use of lasers
Laser Doppler Flowmetry has been explained in a. Laser energy is emitted from the tip of optical
Chapter 7, Diagnosis and Diagnostic aids in Endodontics. fiber or the laser guide and is directed vertically
• Dentinal hypersensitivity: along the root canal but may not be directed
– Lasers used for dentinal hypersensitivity are low laterally to the root canal walls. Thus, laser will
output lasers such as He-Ne and GaAlAs lasers not be able to uniformly cover the entire root
and middle output lasers such as Nd:YAG and CO2 canal surface.
lasers. b. There is potential for thermal damage to the
– CO2 lasers seal the open dentinal tubules as well as periapical tissues.
reduce the permeability of dentinal tubules.
492 Short Textbook of Endodontics
c. There is possibility of transmission of laser rotary instrumentation. This tip is sealed from its far
irradiation beyond the apical foramen in the end, so that there is no transmission of irradiation to
periapical tissues which may be hazardous in and through the apical foramen.
case of teeth which are in close proximity to the – Lasers can be combined with the commonly used
mental foramen or mandibular nerve. irrigants such as 5.25% sodium hypochlorite, 17%
d. Laser light may not be able to eradicate EDTA and 10% citric acid for effective cleaning of the
Endodontic biofilms even on direct laser root canal system. The action of chelating substances
exposure. facilitates the penetration of lasers into the dentinal
– A new Endodontic tip called side-firing spiral tip walls up to 1 mm depth and is found to have stronger
has been developed to be used with Er:YAG laser, decontaminating effect than the chemical agents
in which delivery of laser is through a hollow tube used alone. Laser-activated irrigation has been found
which allows lateral emission of radiation (side- to be very effective in removing debris and smear
firing). It is designed to fit the shape and volume layer from root canals as compared to the traditional
of the root canals prepared using Nickel Titanium techniques and ultrasonics.
• Apicectomy Limitations
– The dentin of the apically resected roots is more • Root canals are rarely straight. They are usually curved
permeable to fluids than the dentin of nonresected at least in two dimensions. Manual Endodontic
roots. instruments (files) can be curved to follow the curvature
– FDA has approved the diode laser for apicectomy. of the root canal. But Lasers travel in straight path. So,
– Advantages of using lasers for periapical surgery are laser probes need to be fabricated that cause laser light
improved hemostasis and concurrent visualization to emerge laterally, uniformly interacting with the root
of the operative field. canal walls.
– When Er:YAG laser is used in a low output power in • Root canal preparation using lasers has not been proved
apical surgery, smooth and clean resected surfaces to be more effective than the mechanical shaping
devoid of charring were observed. procedures.
– Laser converts the apical dentin and cementum • There are hazards related to rise in temperature caused
structure into a uniformly glazed area which does by interaction of laser with the tissue. The increased
not allow egress of microorganisms through dentinal temperature can char the root canal space causing
tubules and other openings in the apex of the tooth. damage to the tooth and its surrounding hard and
• Bleaching of teeth soft tissues. The bone surrounding the tooth may be
– Argon laser is used for bleaching of teeth by chemical irreversibly injured resulting in ankylosis.
oxidation process. • The melting and solidification cycles while root canal
– CO2 laser is used to enhance the bleaching effect preparation using lasers have not shown to have any
caused by Argon laser. positive effect on the clinical outcome.
Figure 32.4A gives the mind-map to remember all
WHAT ARE THE ADVANTAGES AND LIMITATIONS points of Lasers in Endodontics, and Figure 32.4B gives
the mind-map of Laser applications in Endodontics.
OF USING LASERS IN ENDODONTICS?
Advantages BIBLIOGRAPHY
• There is no need of anesthesia 1. AAE Position Statement on Use of Lasers in Dentistry. American
Association of Endodontists. 2012.
• There is no noise in contrast to the noisy dental drills 2. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis:
• Less bleeding Mosby, 2006.pp.20, 279-80, 529-31, 612-3, 852.
• Less chances of infection 3. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics 6, 6th edn.
• Results in faster healing. BC Decker Inc, Hamilton, 2008.pp.857-66.
4. Kimura Y, Wilder-Smith P, Matsumoto K. ‘Lasers in Endodontics-A
Review’, International Endodontic Journal. 2000;33:173-85.
5. Olivi G, Crippa R, Iaria G, Kaitsas V, DiVito E, Benedicenti S. “Laser
in Endodontics-Part I”, Roots 1. 2011.pp.06-9.
33
CHAPTER
This chapter outlines the ethics in dentistry and explains the legal responsibilities of the clinician to
practice Endodontics with optimum standard of care.
You must know
• What is Dental Ethics?
• What are the Principles of Ethics?
• What is Standard of Care?
• What is Dental Negligence and Malpractice?
• What are the Legal Responsibilities of the Clinician while Performing Endodontics?
WHAT IS DENTAL NEGLIGENCE • Files can break in the root canal because of overzealous
or improper use or sometimes due to defective
AND MALPRACTICE?
manufacture of the file.
Violation of standard of care by a provider that results in • Instrument separation is the problem that occurs usually
harm to the patient is called dental negligence. with Ni-Ti instruments due to fatigue, if it is used for
Professional negligence arising out of the doctor-patient more than 1 to 2 times. Instrument binds and separates
relationship is termed as malpractice. inadvertently.
In simple words, negligence is nothing but carelessness • Instrument separation can be considered as an
or inattentiveness and malpractice is the layman term given unfortunate mishap and not negligence or malpractice
to professional negligence. – Patient should be informed about the mishap. The
‘Pathways of Pulp’ — Stephen Cohen’s 9th edition has unbroken end of the file should be saved in a coin
given two reasons for dental negligence to occur: envelope and placed in patient’s treatment record.
1. When the clinician does not possess a reasonable degree Patient should be referred to an Endodontist for
of education and training to act prudently or microscopic retrieval of the separated file or at least
Endodontic Practice: Ethics and Legal Responsibilities 497
patient should be informed that the file is going to made on patient’s record about it and patient should be
be left behind in the root canal and the treatment closely observed with follow-up visits to rule out severe
completed. There is potential for leakage to occur postoperative pain or development of any pathology like
but it has been found that most of the times teeth cyst around the overextended material.
with separated files may remain asymptomatic and
functional for many years. Use of Screw Posts
Overextensions
Good Record Keeping
• Faulty technique can cause overextension of root canal
filling material that results due to over instrumentation, Clinician must document each and every patient’s details
breaking the apical seal. and maintain Endodontic therapy record.
• Permanent harm is unlikely if there is slight over • Endodontic therapy record must contain:
extension. But if gross over extension occurs contacting – Patient’s detailed case history including personal
the vital structures such as inferior alveolar nerve or information, chief complaint, medical and dental
sinus it can cause permanent consequences. history
• Slight to moderate overextensions often repair – Various findings of clinical examination
themselves, so patient need not be informed, only a note – Good quality radiographs
498 Short Textbook of Endodontics
– Details of referral to other specialists has understood all aspects of treatment and accepts the
– Diagnosis recommended treatment. Also, any subsequent changes in
– Proposed treatment plan and informed consent the proposed treatment should be discussed with the patient
– Treatment provided: Emergency or elective treatment and an entry made in the consent form to be signed by the
given along with the date of visit, any problems patient indicating continued acceptance by the patient.
encountered or any complications that occurred
during treatment. Referral to Specialists
– Drug prescriptions
– Any missed appointments and stated reasons for the For a competent ethical practice, the clinician must know
same his limitations. The general practitioner should refer the
– Prognosis case to an Endodontist if it is complicated or has a moderate
– Findings of follow-up visits to high difficulty level and will require procedures that are
– Payment details. beyond the general practitioner’s training or competency.
• Nowadays with increased use of computers in dental Before performing Endodontic treatment that the
clinic, electronic records are being maintained. referring clinician has recommended, the Endodontist must
Clinician must have back up files for all patient records undertake an independent diagnostic and radiographic
and confidentiality of patient information must be examination of the treatment area and the proposed
maintained by various means of protection. treatment plan and any associated medical and dental
• Endodontics includes use of several radiographs — history rather than relying solely on the referring clinician.
pretreatment, intratreatment, post-treatment and follow
up radiographs. Radiographs that lack diagnostic quality Continuing Education
should be retaken and all the radiographs should be
retained. A clinician is legally obligated to be updated about the
• Records should be complete, accurate and well current knowledge and recent technological advances
maintained. in the field of Endodontics. So, the clinician must attend
• Records can serve as means of communication among continuing education courses to update his knowledge and
healthcare professionals whenever required. clinical skills.
• Valid information in the Endodontic therapy records can
serve as an evidence to protect the clinician, confirming Accepting Research-based Endodontic Advances
that accurate diagnosis and proper treatment were
provided, in case of a dental malpractice claim against Many new dental products and techniques are being
the clinician. constantly introduced to improve the quality and success of
Endodontic therapy. A reasonable clinician should review
Informed Consent the Endodontic advances and adopt a particular product or
technique only if it is well-accepted and proved by research.
Before the Endodontic treatment is performed, patient must Clinician must accept the research based facts, which
be informed about the benefits, risks, treatment plan and might require:
alternatives to Endodontic treatment. Informed consent • Giving up those materials and techniques in Endodontics
form should be signed by the patient indicating that patient which had been in use for years but research has now
Endodontic Practice: Ethics and Legal Responsibilities 499
proved them to be inappropriate or inadequate for Figure 33.3 gives the mind-map to remember the legal
root canal therapy. For example, giving up step back responsibilities of clinician.
technique for root canal instrumentation (cleaning and
shaping/biochemical preparation), use of silver points BIBLIOGRAPHY
for obturation.
• Adopting newer materials and techniques in Endodontics 1. Cohen S, Hargreaves KM. Pathways of Pulp, 9th edn. St. Louis:
Mosby. 2006.pp.400-52.
which have proved to be beneficial in root canal therapy. 2. Ingle J, Bakland L, Baumgartner J. Ingle’s Endodontics, 6th edn.
For example, adopting crown-down approach for root BC Decker Inc, Hamilton. 2008.pp.86-103.
canal cleaning and shaping, also use of Nickel-Titanium
instruments, etc.
34
CHAPTER
Regenerative Endodontics
This chapter gives an overview of the upcoming field of Dentistry called Regenerative therapy in relation
to Endodontics, that can bring about regeneration of functional pulp tissue and regain vitality in a
necrotic immature young permanent tooth and also describes the different terminology related to
Regenerative Endodontics.
You must know
• What is Regenerative Endodontics?
• What is Tissue Engineering?
• What are the Mechanisms and Clinical Procedures Related to Regenerative Endodontics?
• What is the Triple Antibiotic Paste?
• What are the Advantages and Limitations of Revascularization Procedure Over Apexification
Procedure for a Necrotic Immature Permanent Tooth with Open Apex?
• What are the Clinical Considerations for Regenerative Endodontics?
• What is the Protocol for Revascularization Endodontic Therapy?
• What are the Clinical Measures for Assessment of Endodontic Revascularization Treatment
Outcome?
• Based on the source of stem cells, they can be classified Growth Factors/Morphogens
as:
• Growth factors are proteins that bind to cell receptors
and act as signals to induce proliferation and/or
differentiation of cells.
• Growth factors trigger the differentiation of selected
mesenchymal stem cells into odontoblast-like cells.
• Growth factors found in dentin and platelets have been
utilized in the Regenerative Endodontic Procedures.
• It has been found that application of dexamethasone
combined with Vitamin D3 increases the differentiation
of human dental pulp cells into odontoblast-like cells.
Other examples of the growth factors include:
– Bone Morphogenetic Protein (BMP) derived from
bone matrix which brings about differentiation of
osteoblasts and bone mineralization. It is used to
induce stem cells to synthesize and secrete mineral
matrix
– The sourcing of embryonic stem cells is unsuitable – Fibroblast Growth Factor (FGF) can promote
for clinical development due to legal and ethical and proliferation of many cells. So, it is used to increase
medical (tissue rejection) issues. So, the researchers the stem cell numbers.
are now focusing attention on developing stem cell – Platelet Derived Growth Factor (PDGF) is obtained
therapies using postnatal stem cells. The postnatal from platelets and endothelial cells. It promotes
stem cells are derived from patient themselves or proliferation of connective tissue cells. It can also
their close relatives. be used to increase stem cell numbers.
– Using stem cells to regenerate entire tooth may not
be practically possible as it takes very long time Scaffolds
(many years) even for natural development of teeth.
But, within a patient’s existing permanent tooth, a • Scaffolds organize the cells into correct spatial
functional pulp-dentin complex may be regenerated position and regulate proliferation, differentiation and
so that it can carry out the natural functions vascularization.
including formation of replacement dentin, tissue • Appropriate scaffold might bind and localize the cells
immunity and neural sensation. selectively.
– Many postnatal mesenchymal stem cells that can • Scaffolds contain growth factors and undergoes
differentiate into odontoblast-like cells have been biodegradation over time.
isolated including: • Blood clot, dentin and Platelet Rich Plasma have been
utilized as scaffolds in few Regenerative Endodontic
Procedures.
• Classification of scaffolds:
Beneficial properties of PRP (Platelet Rich Plasma) development of this paste and this paste was originally
include: used by Banchs and Trope.
• Autologous • It is the medicament used to disinfect the root canal
• Easy to prepare in dental setting space. It can be used as an adjunct to the revasculari
• Forms 3-dimentional fibrin matrix. zation procedure for necrotic pulp space of immature
permanent tooth with open apex as it creates a
WHAT ARE THE MECHANISMS AND CLINICAL favorable environment for ingrowth of vasculature and
PROCEDURES RELATED TO REGENERATIVE regenerative cells by reducing or eradicating bacteria
ENDODONTICS? from the root canal space.
• Research studies show that this antibiotic combination
Terminology
has high efficacy in eradicating the bacteria from
• Apexification: “Apexification is defined as a method to infected dentin of root canals.
induce a calcified barrier in a root with an open apex or • The disadvantage of using this paste is that: There is
the continued apical development of an incompletely potential for Minocycline staining of the crown. This
formed root in teeth with necrotic pulp tissue.” (Pathways can be minimized by restricting the drug below CEJ.
of Pulp, 10th edn.p.608) If such staining occurs, then walking bleach method
• Apexogenesis: “Apexogenesis is defined as vital pulp using sodium perborate can be used to manage
therapy procedure performed to encourage continued discoloration.
physiologic development and formation of the root end.” • This combination is less commonly used in Dentistry.
(Pathways of Pulp, 10th edn.p.608) So it needs additional review. Calcium hydroxide or
• Maturogenesis: Maturogenesis is the term used to Formocresol are used instead of the triple antibiotic
describe the outcome of revascularization procedure paste sometimes.
indicating that a stage is set for physiologic root • Also, this paste is not approved by the US Food and Drug
development. (Pathways of Pulp, 10th edn.p.608) Administration.
• Revascularization: “Revascularization is defined as the
restoration of vascularity to a tissue or organ.” (Pathways WHAT ARE THE ADVANTAGES AND LIMITATIONS
of Pulp, 10th edn.p.608) OF REVASCULARIZATION PROCEDURE OVER
Endodontic Revascularization Treatment aims at APEXIFICATION PROCEDURE FOR A NECROTIC
regaining the vitality and vascularity of pulp tissue in IMMATURE PERMANENT TOOTH WITH OPEN
a necrotic root canal of an immature permanent tooth APEX?
with open apex.
• Guided Tissue Regeneration (GTR): It is induced or Advantages
guided regeneration of the tissues. With revascularization procedure, there is increased
The biologic tissue that fills up the pulp space after the likelihood of:
}
Regenerative Endodontic Procedures (REPs) may be • Increased root length
dental pulp or pulp-like tissue. Completion of root
The desired outcome of Regenerative Endodontic • Increased root development
wall thickness
Procedures (REPs) is regeneration of pulp-dentin
complex. • Increased or maintained root strength.
Till date, most of the studies published, can be best Traditional apexification procedure using calcium
described as “Revascularization” procedures, that hydroxide has been found to affect mechanical
attempt to regenerate biologic tissues (that may not properties of root dentin reducing the root strength,
necessarily replicate the pulp-dentin complex) and bring making it prone to fracture. Also, for apexification
about revascularization within the root canal space. using calcium hydroxide, multiple appointments are
needed for its reapplication and time taken to form
WHAT IS THE TRIPLE ANTIBIOTIC PASTE? calcified bridge is about 3–24 months. However, with
the advent of Mineral Trioxide Aggregate (MTA), these
• The Triple Antibiotic Paste is the mixture of Ciprofloxacin/ limitations of calcium hydroxide apexification have
Metronidazole/Minocycline (CMM) in the ratio of 1:1:1. been overcome as it is found to form a cementum-like
Hoshino and Colleagues greatly contributed to the hard bridge in relatively shorter duration of time and
504 Short Textbook of Endodontics
Limitations
• Although Revascularization procedure causes increased
root thickness in midroot and apical root, but not in
cervical area, making the tooth prone to fracture in that
area.
• Regenerative Endodontic Procedures are limited to
immature teeth as open apex is a ready source of stem Fig. 34.2 Clinical considerations for Regenerative Endodontics
cells. However, its long-term goal should be to treat
mature permanent teeth as well. WHAT IS THE PROTOCOL FOR
• There is ongoing research and trials for the various REVASCULARIZATION ENDODONTIC THERAPY?
Regenerative Endodontic Procedures (REPs). But till
date, no randomized controlled clinical trials have Revascularization Protocol
been published to evaluate the various Regenerative
Case Selection
Endodontic Procedures (REPs) and their potential
adverse events. Also, in case of Regenerative Endodontic Young patient with incompletely developed permanent
therapy in humans, histological evaluation of the tooth with open apex that gives negative response to pulp
treatment outcome is not possible. responsiveness testing.
• Case studies show that with Calcium hydroxide and MTA
apexification, success rates have been as high as 95%. Informed Consent
For Regenerative procedures, there is ongoing research
still going on. Inform patient and guardian about:
• The number of appointments-2 or more and the
WHAT ARE THE CLINICAL CONSIDERATIONS potential benefits of the treatment.
• Adverse effects that may result from the procedure-
FOR REGENERATIVE ENDODONTICS?
Minocycline staining of crown.
• Age: Young patient. • There may be lack of response to treatment
Younger patients have greater healing capacity or stem • Alternative treatment options: MTA apexification, no
cell regenerative potential. treatment or extraction.
• Permanent tooth with immature apex. The large • Possible post-treatment symptoms.
diameter of the immature (open) apex may have rich
source of mesenchymal Stem Cells of the Apical Papilla Procedure
(SCAP).
• Diagnosis of pulp necrosis in such incompletely formed/ First appointment
immature permanent tooth with open apex. • Profound anesthesia
• Minimal or lack of instrumentation of dentinal walls. • Isolation with rubber dam
Since the dentinal walls are not instrumented, smear • Access cavity preparation
layer is not generated that could otherwise occlude the • A small k-file such as no. 10 or 15 is used to scout the
dentinal walls or tubules. root canal system and determination of working length
• Use of an intracanal medicament. using radiograph or paper point method.
Usually the Triple antibiotic paste is left in root canal • Copious irrigation of root canal system using 20
space for few days or weeks. mL of 3–5% NaOCl followed by 20 mL of 0.12–2%
• Creation of a blood clot in the canal that might serve as Chlorhexidine with saline wash in between the two to
a protein scaffold and induces 3-dimensional ingrowth prevent the formation of brownish-orange precipitate.
of tissue. Irrigation should be done using side-vented irrigating
Figure 34.2 lists these considerations in the form of a needle slowly and carefully so as to avoid or minimize
mind-map. the irrigants passing through the open apex.
Regenerative Endodontics 505
A B C
Figs 34.3A to C Schematic representation of pulp regeneration: (A) Immature nonvital permanent tooth with necrotic pulp, SCAP: Stem
cells from apical papilla; (B) Following antimicrobial medicament, in the second appointment, the canal is over-instrumented to cause
bleeding upto cervical level. Over the blood clot, colla plug and MTA seal and coronal seal with composite restoration; (C) Pulp regeneration
is expected that causes completion of root formation
• The root canal system is dried using sterile paper points. Patient is recalled after 12–18 months for follow-up.
• Delivery of antimicrobial medicament such as triple Successful outcome is that pulp regeneration occurs in
antibiotic paste or calcium hydroxide into the root canal the canal that causes completion of root formation with
space. increase in root length and wall thickness (Fig. 34.3C).
• The tooth is sealed with a temporary cement (e.g. Cavit).
WHAT ARE THE CLINICAL MEASURES
Second Appointment (Figs 34.3A to C) FOR ASSESSMENT OF ENDODONTIC
Scheduled after 3–4 weeks REVASCULARIZATION TREATMENT OUTCOME?
• Patient is assessed for resolution of signs and symptoms, Assessment of Endodontic Revascularization treatment
such as pain, swelling, sinus tract, etc. that may have outcome:
been present during the first appointment. • Clinical
• If the resolution of signs and symptoms has not occurred, – Lack of signs and symptoms
the antimicrobial treatment is repeated and patient – Clinical evidence of functioning vital tissue in the
recalled after few weeks. root canal.
• If resolution of signs and symptoms has occurred, then – Pulp testing methods such as heat, cold, electrical,
patient is anesthesized using 3% Mepivacaine. laser Doppler flowmetry suggestive of asymptomatic
(Local anesthetic containing vasoconstrictor is not tooth that does not require retreatment.
used as in this appointment revascularization-induced • Radiographic
bleeding is to be evoked. 3% Mepivacaine facilitates the – Radiographic appearance of increased root wall
ability to trigger bleeding into the root canal system.) thickness that could be due to ingrowth of cementum,
• Rubber dam isolation of tooth and re-establishment of bone, or a dentin-like material.
coronal access. – Healing of periradicular tissues and progression of
• Copious, but slow and careful irrigation with 20 mL root development.
NaOCl along with gentle agitation with small k-file to – Increase in root length.
remove the antimicrobial medicament.
BIBLIOGRAPHY
• Root canal system is dried using sterile paper points.
1. Colleagues for Excellence newsletter Regenerative Endodontics
• A small k-file is placed few mm beyond the apical www.aae.org/colleagues, Spring 2013.
foramen to slightly lacerate the apical tissue causing 2. Hargreaves KM, Law AS. Regenerative Endodontics. Chapter 16.
bleeding up to 3 mm from the CEJ. Pathways of the Pulp, 10th edn. Hargreaves KM, Cohen S, Mosby
• Insert a small piece of colla-plug into the root canal Elsevier, St Louis, MO. 2011.pp.602‐19.
system to serve as resorbable matrix and to restrict MTA 3. Peter E Murray, Franklin Garcia-Godoy, Kenneth M. Hargreaves,
‘Regenerative Endodontics: A Review of Current Status and a Call
positioning (Fig. 34.3B)
for Action’, JOE. 2007;33:4.
• Place MTA in the thickness of 3 mm (Fig. 34.3B) 4. Rudolf Jaenisch, Richard Young, ‘Stem cells, the Molecular
• Achieve good coronal seal using a permanent restoration Circuitry of Pluripotency and Nuclear Reprogramming’, “Cell”
(Fig. 34.3B). Press. 2008;132(4):667-82.
Index
A B pulpotomy 446
with iodoform 275f
Acellular cementum 16 Bacterial virulence factors 89, 90f Calcium phosphate cement obturation
Actinomyces israelii 375 Bacteria-tight seal 406 308
Air emphysema 354 Bacteroides forsythus 415 Camphorated parachlorophenol 276
Alara, principles of 112 Bacteroides melanogenicus 87 Canal blockage 345
Alkaptonuria 384 Barbed broaches 172f Canal obstructions, removal of 381
Allergy 140 Barodontalgia 64 Canal orifices 20, 20f, 213
Alveolar abscess classification of 64 flaring of 204f
acute 74, 328 Bayonet-shaped canals 227f Canal preparation 244
chronic 76 Bioactive glass 276 balanced force technique of 252
Alveolar bone Biomaterial centered infection 95 hybrid technique of 253
proper 17 Bite test 123, 124 Canal system, type of 25
supporting 17 using cotton roll 124f Candida 267
Amalgam 435 Bleaching Candida albicans 415
restoration 458 chemistry of 384 Carbamide peroxide 388
Amelogenesis imperfecta 384 contraindications of 388 Carbide bur, safe-ended 164f
Anesthesia, evaluation of 315 material 391f Carbon fiber-reinforced epoxy resin posts
Antibiotic paste 503 points of 399f 365
Anticurvature filing 254 role of 386 Cardiac pacemaker 168
Anxiety, management of 312 Bleaching of vital teeth 390 Caries and defective restorations, removal
Apexification 446, 503 extracoronal 389f of 203f
calcium hydroxide 448f technique for 389 Caries causing pulpitis 53f
Apexogenesis 503 Bone cyst 118 Caries detector dye 125f, 162f
Apical abscess Bone forming cells 16 Caries
acute 74 Bone morphogenetic protein 502 in dentin 53f
chronic 76 Bone-resorbing cells 16 in enamel 53f
Apical canal transportation, type III 349 Bur 163 Carious dentin
Apical perforation 349f long shank round 163f inner 52f
Apical periodontitis 74 round 163f outer 52f
acute 72 safe-ended 163f Cavity design, poor access 229, 337
chronic 74, 331 sharpness of 58 Cavity preparation 200, 406
Apical third of root transmetal 163f challenging access 226
anatomy of 25f steps of 207
canal, instrument in 343f C Cavity walls 167f, 203, 204
Apical-root fracture 410 Cells of alveolar bone 17
Apical-third filling 307 Calcibiotic root canal sealer 292 Cells of pulp 10
Arterioles 11 Calcium hydroxide 273, 274, 275f, 307, Cellular cementum 14
Arteriovenous anastomoses 11 406, 441, 442, 447, 464 Cemental dysplasia 118
Asymptomatic irreversible pulpitis 68 compounds 442 Cementoblasts 16
Axial wall extension 213, 218 containing sealers 291 Cementodentinal junction 8, 26, 237,
in maxillary molar 208f in canal, application of 275 282
Azithromycin 319 points 274 Cementoenamel junction 202
508 Short Textbook of Endodontics
Endo access bur 206f retreatment 377, 381, 493 Engine-driven handpieces 177
Endoactivator system 278f steps of nonsurgical 377 Engine-driven instruments 177
Endodontic 92 scope of 1, 2f Enterococcus faecalis 87, 278, 374
access cavity preparation 199, 200 sonics and ultrasonics in 180f Epiphany sealer 293
advances, research-based 498 spoon excavator 167f, 207f Erythroblastosis fetalis 384
armamentarium 158 surgery 425, 473 Extracellular polymeric substances 92
biofilm 94 classification of 427 Extracoronal bleaching 396f
types of 97f in geriatric patients 473 of vital teeth 391, 392f
cases 373 postoperative sequelae 437f Extraoral examination 106
diagnosis aids in 98, 161 role of 146
diagnosis, accurate 129 surgical 425 F
disease 102, 103t, 418, 424 armamentarium 429
drugs used in 318f phase 430 Ferric sulfate pulpotomy 461
emergencies 323-325, 331 procedure 29 Ferrule effect and biologic width 361,
after treatment 335 role of isthmi in 29 362f
before treatment 326 therapy 130, 138 Fiberoptic endoscope 161
classification of 325 treatment 140, 150, 150f, 156f, 337, Fiberoptic light for transillumination test
midtreatment 323 373, 374, 387, 469, 472 125f, 162f
treatment, Weine’s classification drugs used in 311, 312 Fibers 11
of conditions 325 failure 497 Fibroblast growth factor 502
explorer 167f in geriatric patient 471 Finger plugger for obturation 187f
failure 373 inadequate 415 Finger-held spreader for obturation 186f
causes of 374, 376 of pediatric patients 450 Fissure carbide bur 164
classification of 376 plan 145, 146f Flap design, triangular 431f
gauge 242f revascularization 505 Flap reflection 431, 432
infections 86, 87 success of 357 Focal infection 83
control in 192 triad 199 mechanism of 131
types of 88f use of theory 83, 130
instruments 158, 196 sonic devices for 178 origin of 83
asepsis and sterilization of 192 sonics in (endosonics) 179 Focal sclerosing osteomyelitis 79
aspiration of 496 ultrasonics (endosonics) 179 Formaldehyde 276
classification of 169 Endodontically treated mandibular Formocresol pulpotomy 445
disinfection of 198 second molar 343f Foundation restoration 371
interpretation in 116 Endodontically treated teeth 355, 356, Fungi 415
lesions 415, 418 356f
primary 418 changes on 357f G
management, nonsurgical 373 physical changes on 356f
materials 158 post systems for 190 Galilean optical system 159
microbiology 83 restoration of 190, 355 Gates-Glidden drills 164, 166f, 177
microbrushes 277f Endodontic-periodontal diseases 415 Genera actinomyces 374
mishaps 336, 336f, 337 Endodontic-periodontal lesion 422 Geriatric dentistry 468
classification of 337 classify 416 Geriatric endodontics 468
classify 336 types of 418, 424 scope of 468, 469f
management 336 Endodontic-periodontal problems Geriatric patient
prevention 336 Weine’s classification of 422 abrasion 471f
past and present 4t types of 423t attrition 471f
periodontal diseases 416f Endodontist, enigma to 42 erosion 471f
practice, malpractice in 496 Endoflare 258f Giant cell granuloma 118
preparation in maxillary premolar Endometrics 234 Gingival irritation 391, 398
215 Endovac irrigation system 279f Gingival recession 471f
510 Short Textbook of Endodontics
Gingival sulcus 340 Hydrogen peroxide 269, 388 Lingual shoulder, removal of 210f, 213
Glass bead sterilizers 196f for bleaching 388f, 389 Liquid EDTA for removal of smear layer
Glass fiber posts 365f for irrigation 269f 273f
Glass fiber-reinforced epoxy resin posts Hyperplastic pulpitis, chronic 53, 68 Local anesthesia, armamentarium for
365 Hypoplastic maxillary teeth 106f 163
Glass ionomer 458, 461f Luxation injuries 410
cement 61, 458 I management of 410
core 368 Lymphocytes 11
sealers 293 Immunity in endodontics, role of 135 Lysosomal enzymes 133
Glutaraldehyde pulpotomy 460 Infection, elimination of 317
Glutaraldehyde, advantages of 460 Infection, prevention of 317 M
Gram stain technique, classification to 87 Inflammatory cells 132
Gram-negative anaerobic bacteria 267 Inflammatory paradental cyst 118 Magnifying loupe 206f
Grossman’s classification 375 Ingle’s endodontics 476 Mandibular anesthesia 313
of endodontic emergencies 326 Intracanal brushes 277 Mandibular anterior teeth 219, 396f
Grossman’s sealer 290 Intracanal medicaments 273 Mandibular canine 41, 42f, 221
Gutta-percha 283 antibiotic containing 276 Mandibular central incisor 40, 41f, 219
canal-warmed 299 Intracanal microbial biofilms 94 with two canals 41f
carrier-based 285 Intracoronal bleaching 385, 387, 388, 392 and lateral incisor 41f
chemically plasticized cold 299 of endodontically treated teeth, side Mandibular first molar 44, 45f, 125f, 224,
compaction of 186 effects of 397 224f, 386f, 441f
cone 419 of maxillary right central incisor 395f deep occlusal 441f
for newer obturation systems 285 of teeth, side effects of 399f mesial root of 110f
lateral compaction of 295 Intraligamentary injection 314, 314f periradicular infection in 86f
removal of 187 Intraoral examination 106 proximal caries approaching pulp 441f
removal techniques 380 Intraosseous injection 314, 314f pulp, deep occlusal caries in 110f
sterilization of 296 Intrapulpal hemorrhage 385 tooth
stick 285 Intrapulpal injection 315f osteitis in relation to 79f
heated 121f Irreversible pulpitis 68 postoperative 46f
technique in immature permanent tooth 446 preoperative 46f
solid core carrier-based 306 with acute apical periodontitis 326 with canals 225f
thermoplasticized injectable 306 causes 327 with endodontic 421f
thermoplasticized 285, 306 signs 326 with extensive caries pulp 53f, 74f
with additives 285 symptoms 326 with five canals 45f
with sealants, solid core 295 Irrigant-related mishaps 333 with four canals 45f
with pulp polyp 143f
H L with radix entomolaris
postoperative 46f
Halogens 276 Laser Doppler flowmetry 122, 403 preoperative 46f
Hand-operated instruments 170 in dentistry 123 with severe periodontal lesion 421
Hank’s balanced salt solution 412 Laser light emission 489 with three canals 45f
Hard tissue surgical access 432 Laser-assisted root canal preparation with three mesial canals
Healing of perforation 340 technique 261 postoperative 46f
Hemorrhage from surgical site, Lasers preoperative 46f
management of 433 classification of 490 Mandibular first premolar 42, 43f, 221
Hemostasis 406 in endodontics 488, 491-493 with one and two canals 222f
Hertwig’s epithelial root sheath 77 advantages of 494 Mandibular first primary molar 452, 453f
Holmium:yttrium-aluminium-garnet properties of 488 Mandibular lateral incisor 41, 42f, 221
laser 278 types of 490 Mandibular left central incisor 394f
Hydrochloric acid-pumice abrasion 398 Lingual opposite buccal 116f discolored 394f
Index 511
Mandibular molar Maxillary anterior region 457f Maxillary right lateral incisor
cavity preparation in 225f Maxillary anterior teeth 211, 213f, 478 infection from 107f
taurodontism in 32f cavity preparation for 213f tooth, abscess in relation to 76f
teeth 223 Maxillary canine 34, 34f, 214 Maxillary second and third molars,
with deep carious lesion 419f cavity form of 214f concresence of 31f
Mandibular posterior teeth, in child 454f postoperative 35f Maxillary second molar 39, 39f, 219
Mandibular premolar preoperative 35f carious destruction of 356f
cavity preparation of 222f Maxillary central incisor 32, 33f, 211 cavity form of 219f
teeth 221 cavity form of 213f with canal 39f
Mandibular primary incisors 451, 452f tooth with four canals 40f
Mandibular second molar 47, 47f, 224 postoperative 33f with three canals 39f, 40
C-shaped canal in 27f preoperative 33f with two canals 39f
tooth with rubber dam 154f Maxillary second premolar 36, 36f, 216
osteitis in relation to 79f Maxillary first and second premolars cavity form of 217f
postoperative 48f postoperative 36f tooth 37f
with C-shaped canal 47f, 48f, 225f preoperative 36f Maxillary second primary molar 452, 453f
postoperative 48f Maxillary first molar 37, 37f, 218 Maxillary sinus 427
preoperative 48f cavity form of 218f Maxillary teeth
with four canals 47f cavity preparation of 219f extracoronal bleaching of 396f
with three canals 47f tooth, MB2 canal in 120f in child 454f
with two canals 47f with four canals 38f Maxillary third molar 39, 40f, 219
Mandibular second premolar 44, 44f, 222 postoperative 38f cavity preparation of 219f
cavity form of 223f preoperative 38f with three canals 40f
tooth 44f with three canals 38f Medicated sealers 293
with root and root canals postoperative 38f Melton’s classification of C-shaped
postoperative 45f preoperative 38f canals 27
preoperative 45f with two palatal canals 38f Memory t-cells 132
Mandibular second primary molar 452, Maxillary first premolar 35, 35f, 215 Mesenchymal cells 11
453f, 462f cavity form of 216f Mesial and distal boundary 218
Mandibular teeth, periodontal tooth Mesial angulation 116f
involvement in 144f postoperative 36f Mesial canal 225f
Mandibular third molar 47, 48f, 226 preoperative 37f Mesiobuccal canal, second 218
cavity preparation in 226f with S-shaped, cases of 227f Metal-core obturation 286
curved canals Maxillary first primary molar 452, 453f Metallic core materials 367
postoperative 49f Maxillary lateral incisor 33, 34f, 214, Metronidazole 319
preoperative 49f 386f Micro-endodontics, instruments for 161
Mast cells 11 cavity form of 214f Mid-root fractures 410
Materials Maxillary molar 217f Midtreatment flare-ups 334f
bleaching 388 cavity preparation for 217f Mineral trioxide aggregate 357, 436, 439,
disinfection of root canal 169 teeth 217 443, 448
isolation of endodontic field 163 Maxillary posterior region 457f pulpotomy 446
obturation 282 Maxillary premolar teeth 215 Mishaps related to post placement 353
postendodontic restoration 190 cavity preparation for 215 Monocytes and macrophages 475
vital pulp therapy, techniques and Maxillary primary incisors 451, 452f Motor for rotary instrumentation 184f
439 Maxillary rhinosinusitis 102 Mouse-hole effect 201f
Maturogenesis 503 Maxillary right central incisor MTA pulpotomy 461
Maxilla, posterior 427 discolored 386f, 394f Mucoperiosteal flap 431
Maxillary and mandibular primary fracture in endodontically treated Multi-lens optic system 159
canine 452, 452f 330f Multirooted teeth, post placement in 366
Maxillary anesthesia 315 internal resorption in 478f Myofascial pain vs pulpal pain 103
512 Short Textbook of Endodontics
Root and root canal system 425 Root canal system 19 Rotary instrumentation 254
Root apex, anatomy of 26 activation of irrigants in 277f Roth’s sealer 290
Root canal 31f, 87f, 117, 351f anatomic complexities in 26 Rubber dam
anatomy of apical portion of 25 anatomic components of 19 clamps 152f
apical width of 240f anatomy of 21, 29 forceps 153, 153f
bacteria in infected 87 classification of 22 frame 152, 152f
biomechanical preparation of 231 components of 20f in endodontic treatment in
cavity preparation of 163, 199 disinfection of 264, 265, 491 mandibular first molar 154f
cleaning and shaping of 231, 232 in geriatric patient 470f material 151
components of 20 in root, types of 21 placement 153
delivery of sealers in 187 in young adult tooth 470f punch 153, 153f
effective shaping of 243 internal anatomy of 19 sheet 151, 152f
infected 86 morphology of 32, 34, 35 components of 151
instruments of 186 obturation of 280, 472
ledge formation in 347f of individual teeth 32 S
microbes from 89 solutions in 276
microbial flora of 84 Weine’s classification of 23f Schilder technique 299
microbiology of infected 89f with increasing age 21f Sealapex root canal sealer 291f
obturation of 186, 280, 281, 493 Root canal treatment 1, 139, 141, 419 Sealer placed in root canal 288
shaping of 464f Root end cavity preparation 435 Sickel cell anemia 384
underfilling of 335 advantages of 435 Silicone-based sealers 293
Root canal anatomy of individual teeth, Root end Silver amalgam 61, 461
primary 451 beveling of 434f restorations 392
Root canal disinfectant 265 conditioning 435 Silver point 287f
Root canal filling material 283 development 448f obturation with 295f, 497
classification of 283 management 434 removal of 189, 379
Root canal infections 87 resection 434 Smear layer 272f
Root canal instruments 170, 171f Root fracture 117, 118, 329, 354, 372, 409, in endodontics, management
Root canal irrigants 248, 265, 267 413 of 272
Root canal of primary teeth 464 crown 409 removal of 271
Root canal opening 145, 323 of palatal root of maxillary second Sodium hypochlorite 267, 268, 269f, 356,
Root canal orifices 209 premolar tooth 120f 381, 446
exploration of all 204 Root perforations 415 accidents 268, 350
flaring and exploring 204f Root resection 422 efficacy of 268
Root canal preparation 233, 263, 491 Root resorption 117 for irrigation 267f
crown-down technique of 248, 250 classification of 475 Sodium perborate 388
devices for 169 differences between external and Sound tooth structure remaining-
hand instruments for 172 internal 480 nonrestorable tooth 144f
instruments for 169 external 79, 80f, 117, 476, 476f Stainless steel and nickel-titanium
of apical third and body of canal 247f cervical 397 instruments 181t
rotary instrumentation 254 internal 117, 478, 478f properties of 181
sonics 261 mechanism of 475 Stem cells 501
step down technique of 250 types of types of 501
step-back method of 245 external 476 Step-back technique v/s crown-down
steps of crown-down technique of 249 internal 479 technique 252, 252t
techniques of 244, 245, 254 Root-end resection, angle of 434 Streptococcus faecalis 87
terminology for 241 Roots and root canals, anatomy of 227 Strontium chloride 485
ultrasonics 261 Roots of maxillary molar, apical third of Stropko irrigator 266
Root canal sealers 282, 288, 288f, 289 31f Sulfur granules 95
in obturation 289 Rotary endodontic file, components of Supernumerary roots 32
paraformaldehyde-based 497 181f Superoxidized water 276
Index 515