Sturdevant's Art and Science of Operative Dentistry - South Asian Edition
Sturdevant's Art and Science of Operative Dentistry - South Asian Edition
Sturdevant's Art and Science of Operative Dentistry - South Asian Edition
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US Editors
Harald O Heymann, DDS, MEd
Professor, Department of Operative Dentistry
The University of North Carolina, School of Dentistry
Chapel Hill, NC
Edward J Swift, Jr, DMD, MS
Professor and Chair, Department of Operative Dentistry
The University of North Carolina, School of Dentistry
Chapel Hill, NC
André V Ritter, DDS, MS
Professor and Graduate Program Director, Department of Operative Dentistry
The University of North Carolina, School of Dentistry
Chapel Hill, NC
Adaptation Editor
V Gopikrishna, MDS, FISDR
Professor
Department of Conservative Dentistry and Endodontics
Thai Moogambigai Dental College
Dr MGR Educational and Research Institute University
Chennai, INDIA
ELSEVIER
A division of
Reed Elsevier India Private Limited
Contributors vii
List of Reviewers ix
Preface xi
Acknowledgements xiii
Chapter 14 Class I, II, and VI Direct Composite Restorations and Other Tooth-colored Restorations 255
xv
1
Clinical Significance of Dental Anatomy, Histology,
Physiology and Occlusion
“Success in life is founded upon attention to the smallest the function of teeth; class traits are the characteris-
of things… rather than to the largest of things…” tics that place teeth into functional categories. Be-
—BOOKER T WASHINGTON cause the diet of humans consists of animal and plant
foods, the human dentition is called omnivorous.
A thorough understanding of the histology, physiol-
ogy, and occlusal interactions of the dentition and Incisors
supporting tissues is essential for the restorative den-
tist. Knowledge of the structures of teeth (enamel, The incisors are located near the entrance of the oral
dentin, cementum, and pulp) and their relationships cavity and function as cutting or shearing instru-
to each other and to the supporting structures is nec- ments for food (see Fig. 1.1). From a proximal view,
essary, especially when treating dental caries. Proper the crowns of these teeth have a relatively triangular
tooth form contributes to healthy supporting tissues.
The relationships of form to function are especially Canine Molars
noteworthy when considering the shape of the dental Incisors Premolars
arch, proximal contacts, occlusal contacts, and man-
dibular movement.
Dentitions
Humans have primary and permanent dentitions.
The primary dentition consists of 10 maxillary and
10 mandibular teeth. Primary teeth exfoliate and are
replaced by the permanent dentition, which consists
of 16 maxillary and 16 mandibular teeth.
Incisors Premolars
Canine Molars
Classes of Human Teeth:
Form and Function Fig. 1.1 Maxillary and mandibular teeth in maximum
intercuspal position. The classes of teeth are incisors,
Human teeth are divided into classes on the basis of canines, premolars, and molars. Cusps of mandibular teeth
form and function. The primary and permanent den- are one-half cusp anterior of corresponding cusps of teeth in
titions include the incisor, canine, and molar classes. the maxillary arch. (From Logan BM, Reynolds P, Hutchings
The fourth class, the premolar, is found only in the RT: McMinn’s color atlas of head and neck anatomy, ed 4,
permanent dentition (Fig. 1.1). Tooth form predicts Edinburgh, Mosby, 2010).
shape, with a narrow incisal surface and a broad cer- (TMJ), which serves as the fulcrum during function.
vical base. During mastication, incisors are used to These teeth have a major role in the crushing, grinding,
shear (cut through) food. and chewing of food to the smallest dimensions
suitable for swallowing. They are well suited for this
task because they have broad occlusal surfaces and
Clinical Notes
multirooted anchorage (Fig. 1.2).
Incisors are essential for the proper esthetics of the
smile, facial soft tissue contours (e.g. lip support),
and speech (phonetics). Clinical Notes
Premolars and molars are important in maintaining the
Canines vertical dimension of the face (see Fig. 1.1).
Clinical Notes
4 7
Canines not only serve as important guides in occlu-
sion because of their anchorage and position in the 8
dental arches but also play a crucial role (along with
the incisors) in the esthetics of smile and lip support
(see Fig. 1.1). 6
Premolars
3c 5
Premolars serve a dual role:
(1) They are similar to canines in the tearing of
food. 10
11
(2) They are similar to molars in the grinding of
food. 3a 9
The occlusal surfaces of the premolars present a
series of curves in the form of concavities and con- 3b 12
2
vexities that should be maintained throughout life for
correct occlusal contacts and function.
1a
13
Clinical Notes 1
2
Dental Caries: Etiology and
Clinical Characteristics
“You don’t know how much you know… • Pathologic factors (i.e. those favoring demineraliza-
Until you know how much you don’t know…” tion)
This chapter presents basic definitions, terminologies • Protective factors (i.e. those favoring remineraliza-
and information on dental caries, and clinical charac- tion).2
teristics of the caries lesion in the context of clinical Individuals in whom the balance tilts predomi-
operative dentistry. nantly toward protective factors (remineralization)
are much less likely to develop dental caries than
Definition those in whom the balance is tilted toward patholog-
ic factors (demineralization). Understanding the bal-
Dental caries is defined as a multifactorial, transmis- ance between demineralization and remineralization
sible, infectious oral disease caused primarily by the is the key to caries management.
complex interaction of cariogenic oral flora (biofilm)
with fermentable dietary carbohydrates on the tooth Clinical Notes
surface over time.
It is essential to understand that caries lesions, or cavi-
tations in teeth, are signs of an underlying condition,
an imbalance between protective and pathologic factors
Demineralization – favoring the latter. In clinical practice, it is very easy
Remineralization Balance to lose sight of this fact and focus entirely on the re-
storative treatment of caries lesions, failing to treat the
underlying cause of the disease (Table 2.1). Although
Traditionally, the tooth-biofilm-carbohydrate interac- symptomatic treatment is important, failure to identify
tion has been illustrated by the classical Keyes-Jordan and treat the underlying causative factors allows the dis-
diagram.1 However, dental caries onset and activity ease to continue.
are, in fact, much more complex than this three-way
interaction, as not all persons with teeth, biofilm, and
consuming carbohydrates will have caries over time.
Several modifying risk and protective factors influ-
Etiology of Dental Caries
ence the dental caries process, as will be discussed
Dental caries is a disease that is dependent on the
later in this chapter (Fig. 2.1).
complex inter-relationships between the following
At the tooth surface and sub-surface level, dental
five critical parameters:
caries results from a dynamic process of attack
(demineralization) (Figs. 2.2 and 2.3) and restitution i Biofilm
(remineralization) of the tooth matter. This cycle is ii Tooth habitat
summarized in Box 2.1. iii Diet
The balance between demineralization and rem- iv Saliva
ineralization has been illustrated in terms of: v Oral hygiene.
25
Table 2.6
Clinical characteristics of normal and altered enamel
Hydrated Desiccated Surface texture Surface hardness
Normal enamel Translucent Translucent Smooth Hard
Hypocalcified enamel Opaque Opaque Smooth Hard
Noncavitated caries Translucent Opaque Smooth Softened
Active caries Opaque Opaque Cavitated Very soft
Inactive caries Opaque, dark Opaque, dark Roughened Hard
Table 2.7
Clinical significance of enamel lesions
Nonrestorative,
therapeutic treatment
Restorative
Plaque biofilm Enamel structure (e.g. remineralization,
treatment
antimicrobial, pH
control)
Normal enamel Normal Normal Not indicated Not indicated
Hypocalcified enamel Normal Abnormal, but not weakened Not indicated Only for esthetics
Noncavitated caries Cariogenic Porous, weakened Yes Not indicated
Active caries Cariogenic Cavitated, very weak Yes Yes
Inactive caries Normal Remineralized, strong Not indicated Only for esthetics
Odontoblast
a b
Tubule Sclerotic dentin formation occurs ahead of the
demineralization front of a slowly advancing lesion
and may be seen under an old restoration.
Sclerotic dentin is usually shiny and darker in
color but feels hard to the explorer tip. By contrast,
normal, freshly cut dentin lacks a shiny, reflective
surface and allows some penetration from a sharp ex-
A plorer tip.
The apparent function of sclerotic dentin is to wall
1 2 3
off a lesion by blocking (sealing) the tubules.
The permeability of sclerotic dentin is greatly re-
duced compared with normal dentin because of the
decrease in the tubule lumen diameter.24
2. Reaction to a moderate-intensity attack
B The second level of dentinal response is to moderate-
12 3 intensity irritants by forming reparative dentin.
Fig. 2.28 Normal and carious dentin. A, As dentin grows, Mechanism of reparative dentin formation
odontoblasts become increasingly compressed in the The mechanism of reparative dentin formation is ex-
shrinking pulp chamber, and the number of associated plained in Flowchart 2.1.
tubules becomes more concentrated per unit area. The more
recently formed dentin near the pulp (a) has large tubules Infected dentin contains a wide variety of pathogenic materials
with little or no peritubular dentin and calcified intertubular or irritants, including high acid levels, hydrolytic enzymes,
dentin filled with collagen fibers. Older dentin, closer to bacteria, and bacterial cellular debris
the external surface (b), is characterized by smaller, more
widely separated tubules and a greater mineral content in
intertubular dentin. Horizontal lines indicate predentin;
diagonal lines indicate increasing density of minerals; darker The pulp may be irritated sufficiently from high acid levels
horizontal lines indicate densely mineralized dentin and or bacterial enzyme production to cause the formation (from
undifferentiated mesenchymal cells) of replacement odontoblasts
increased thickness of peritubular dentin. B, Carious dentin
(secondary odontoblasts)
undergoes several changes. The most superficial infected
zone of carious dentin (3) is characterized by bacteria filling
the tubules and granular material in the intertubular space.
As bacteria invade dentinal tubules, if carbohydrates are These cells produce reparative dentin (reactionary dentin) on
available, they can produce enough lactic acid to remove the affected portion of the pulp chamber wall (see Figs. 2.28B )
peritubular dentin. Pulpal to (below) the infected dentin is
a zone where the dentin appears transparent in mounted Flowchart 2.1 Mechanism of reparative dentin formation
whole specimens. This zone (2) is affected (not infected)
carious dentin and is characterized by loss of mineral in
the intertubular and peritubular dentin. Many crystals can Clinical Notes
be detected in the lumen of the tubules in this zone. The
crystals in the tubule lumen render the refractive index of • This dentin is different from the normal dentinal ap-
the lumen similar to that of the intertubular dentin, making position that occurs throughout the life of the tooth by
primary (original) odontoblasts.
the zone transparent. Normal dentin (1) is found pulpal to
• The structure of reparative dentin varies from well-
(below) transparent dentin.
organized tubular dentin (less often) to very irregular
atubular dentin (more often), depending on the sever-
ity of the stimulus.
Hypermineralized areas may be seen on radio- • Reparative dentin is an effective barrier to diffusion of
material through the tubules and is an important step
graphs as zones of increased radiopacity (often S-
in the repair of dentin.
shaped following the course of the tubules) ahead of • Severe stimuli also can result in the formation within
the advancing, infected portion of the lesion. This re- the pulp chamber of unattached dentin, termed pulp
pair occurs only if the tooth pulp is vital. stones, in addition to reparative dentin.
• The pulpal blood supply may be the most important
Sclerotic dentin Dentin that has more mineral con- limiting factor for the pulpal responses.
tent than normal dentin is termed sclerotic dentin.
3
Dental Caries:
Risk Assessment and Management
49
4
Patient Assessment, Examination,
Diagnosis and Treatment Planning
73
Clinical Notes
• It cannot be overemphasized that the explorer must not
be used to determine a ‘stick’, or a resistance to with-
drawal from a fissure or pit.
• This improper use of a sharp explorer has been shown
to irreversibly damage the tooth by turning a sound,
remineralizable subsurface lesion into a possible cav-
Fig. 4.4G Non-hereditary hypocalcified areas on facial itation that is prone to progression.5-8 The use of the
surfaces. These areas may result from numerous factors dental explorer for this purpose was found to fracture
but do not warrant restorative intervention unless they are enamel and serve as a source for transferring pathogen-
esthetically offensive or cavitation is present. ic bacteria among various teeth.9,10 Therefore, the use
of a sharp explorer in diagnosing pit-and-fissure caries
is contraindicated as part of the detection process.
Role of Explorer Caries lesions can be detected by
visual changes in tooth surface texture or color or in
tactile sensation when an explorer is used judiciously 2. Radiographic examination Proximal surface car-
to detect surface roughness by gently stroking across ies is usually diagnosed radiographically13 (Fig. 4.7A).
the tooth surface. The recommended instrument for When caries has invaded proximal surface enamel
ICDAS code 0 1 2 3 4 5 6
Definitions Sound tooth surface; First visual change Distinct visual change Localized enamel Underlying dark Distinct cavity with Extensive distinct
no caries change in enamel; seen only in enamel; seen when breakdown with no shadow from dentin, visible dentin; frank cavity with dentin;
after air drying (5 after air drying or wet, white or colored, visible dentin or with or without cavitation involving cavity is deep and
sec); or hypoplasia, colored, change “thin” “wider” than the underlying shadow; localized enamel less than half of a wide involving more
wear, erosion, and limited to the confines fissure/fossa discontinuity of breakdown tooth surface than half of the tooth
other noncaries of the pit and fissure surface enamel,
phenomena area widening of fissure
Histologic depth Lesion depth in P/F Lesion depth in P/F Lesion depth in P/F Lesion depth in P/F Lesion depth in P/F Lesion depth in P/F
was 90% in the outer was 50% inner enamel with 77% in dentin with 88% into dentin with 100% in dentin 100% reaching inner
enamel with only 10% and 50% into the 1/3 dentin
into dentin outer 1/3 dentin
Sealant/restoration Sealant optional Sealant optional Sealant optional or Sealant or minimally Minimally invasive Minimally invasive Minimally invasive
Recommendation DIAGNOdent may DIAGNOdent may caries biopsy if invasive restoration restoration restoration restoration
for low risk be helpful be helpful DIAGNOdent is 20-30 needed
Sealant/restoration Sealant optional Sealant recommended Sealant optional or Sealant or minimally Minimally invasive Minimally invasive Minimally invasive
Recommendation DIAGNOdent may DIAGNOdent may be caries biopsy if invasive restoration restoration restoration restoration
for moderate risk be helpful helpful DIAGNOdent is 20-30 needed
Sealant/restoration Sealant recommended Sealant recommended Sealant optional or Sealant or minimally Minimally invasive Minimally invasive Minimally invasive
Recommendation DIAGNOdent may be DIAGNOdent may be caries biopsy if invasive restoration restoration restoration restoration
for high risk * helpful helpful DIAGNOdent is 20-30 needed
Sealant/restoration Sealant recommended Sealant recommended Sealant optional or Sealant or minimally Minimally invasive Minimally invasive Minimally invasive
Recommendation DIAGNOdent may be DIAGNOdent may be caries biopsy if invasive restoration restoration restoration restoration
for extreme risk ** helpful helpful DIAGNOdent is 20-30 needed
* Patients with one (or more) cavitated lesion(s) are high-risk patients. ** Patients with one (or more) cavitated lesion(s) and xerostomia are extreme-risk patients.
*** All sealants and restorations to be done with a minimally invasive philosophy in mind. Sealants are defined as confined to enamel. Restoration is defined as in dentin. A two-surface restoration is defined as a
preparation that has one part of the preparation in dentin and the preparation extends to a second surface (note: the second surface does not have to be in dentin). A sealant can be either resin-based or glass
ionomer. Resin-based sealants should have the most conservatively prepared fissures for proper bonding. Glass ionomer should be considered where the enamel is immature, or where fissure preparation is not
desired, or where rubber dam isolation is not possible. Patients should be given a choice in material selection.
Fig. 4.5 International caries detection and assessment system (ICDAS) chart showing visual caries detection. (From Jenson
L, Budenz AW, Featherstone JD, et al: Clinical protocols for caries management by risk assessment, J Calif Dent Assoc
35:714, 2007).
7
Instruments and Equipment for
Tooth Preparation
111
Clinical Notes reinforces the cutting edge and reduces the likelihood
for the edge of the blade to fracture.
Runout is the more significant term clinically because
it is the primary cause of vibration during cutting and Clearance angle The clearance angle eliminates
is the factor that determines the minimum diameter of rubbing friction of the clearance face, provides a stop
the hole that can be prepared by a given bur. Because of to prevent the bur edge from digging into the tooth
runout errors, burs normally cut holes measurably larger structure excessively, and provides adequate flute
than the head diameter. space or clearance space for the chips formed ahead
of the following blade. An increase in the clearance
angle causes a decrease in the edge angle.
Bur Blade Design
The actual cutting action of a bur (or a diamond) occurs Clinical Notes
in a very small region at the edge of the blade (or at the
point of a diamond chip). In the high-speed range, this • The three angles cannot be varied independently of
effective portion of the individual blade is limited to no each other.
• Carbide burs normally have blades with slight negative
more than a few thousandths of a centimeter adjacent
rake angles and edge angles of approximately 90 degrees.
to the blade edge. Figure 7.22 is an enlarged schematic • Their clearance faces either are curved or have two sur-
view of this portion of a bur blade. Several terms used faces to provide a low clearance angle near the edge and
in the discussion of blade design are illustrated. a greater clearance space ahead of the following blade.
Each blade has two sides—the rake face (toward
the direction of cutting) and the clearance face—and II. Diamond Abrasive Instruments
three important angles—the rake angle, the edge an-
gle, and the clearance angle. The second major category of rotary dental cutting in-
struments involves abrasive cutting rather than blade
Rake angle The rake angle is the most important cutting. Abrasive instruments are based on small, an-
design characteristic of a bur blade. A rake angle is gular particles of a hard substance held in a matrix
said to be negative when the rake face is ahead of the of softer material. Cutting occurs at numerous points
radius (from cutting edge to axis of bur), as illustrated where individual hard particles protrude from the
in Figure 7.22. For cutting hard, brittle materials, a matrix, rather than along a continuous blade edge.
negative rake angle minimizes fractures of the cutting
edge, increasing the tool life. Terminology
Edge angle Carbide bur blades have higher hardness Diamond abrasive instruments consist of three parts
and are more wear-resistant, but they are more brittle (Fig. 7.23):
than steel blades and require greater edge angles
1. Metal blank
to minimize fractures. Increasing the edge angle
2. Powdered diamond abrasive
3. Metallic bonding material that holds the dia-
mond powder onto the blank.
Rake The diamonds employed are industrial diamonds,
angle To axis of bur
either natural or synthetic, that have been crushed to
powder, then carefully graded for size and quality.
The shape of the individual particle is important
because of its effect on the cutting efficiency and du-
Edge angle
rability of the instrument, but the careful control of
particle size is probably of greater importance.
Rake The diamonds generally are attached to the blank
face Clearance by electroplating a layer of metal on the blank while
angle
holding the diamonds in place against it.
Clearance face
Classification
Direction of rotation
Diamond instruments currently are marketed in myr-
Fig. 7.22 Bur blade design. Schematic cross-section viewed iad head shapes and sizes (Table 7.4) and in all of the
from shank end of head to show rake angle, edge angle, and standard shank designs. Most of the diamond shapes
clearance angle. parallel those for burs (Fig. 7.24).
9
Fundamentals of Tooth Preparation and
Pulp Protection
159
Definition Factors
Establishing the outline form means: In determining the outline form of a proposed tooth
preparation, certain conditions or factors must first
1. Placing the preparation margins in the positions
be assessed. These conditions affect the outline form
they will occupy in the final preparation except
and often dictate the extensions.
for finishing enamel walls and margins.
i. The extent of the caries lesion, defect, or faulty
2. Preparing an initial depth of 0.2–0.5mm pul-
old restoration affects the outline form of the
pally of the DEJ position or 0.8mm pulpally to
proposed tooth preparation because the objec-
normal root-surface position (no deeper initially
tive is to extend to sound tooth structure except
whether in the tooth structure, air, old restora-
in a pulpal direction.
tive material, or caries unless the occlusal enam-
ii. Esthetic considerations not only affect the
el thickness is minimal, and greater dimension
choice of restorative material but also the design
is necessary for the strength of the restorative
of the tooth preparation in an effort to maximize
material) (Fig. 9.6).
the esthetic result of the restoration.
iii. Correcting or improving occlusal relationships
Principles
also may necessitate altering the tooth preparation
The three general principles on which outline form is
to accommodate such changes, even when the in-
established regardless of the type of tooth preparation
volved tooth structure is not faulty (i.e. a cuspal
being prepared are as follows:
form may need to be altered to effect better occlu-
1. All unsupported or weakened (friable) enamel sal relationships).
usually should be removed. iv. The desired cavosurface marginal configuration
2. All faults should be included. of the proposed restoration affects the outline
3. All margins should be placed in a position to form. Restorative materials that need beveled
allow finishing of the margins of the restoration. margins require tooth preparation outline form
0.75 mm
701
0.2 mm
DEJ
0.5 mm CEJ
DEJ B
0.75 - 0.8 mm
0.2 mm
DEJ
A
Fig. 9.6 Initial tooth preparation stage for conventional preparations. A,
B, and C, Extensions in all directions are to sound tooth structure, while
maintaining a specific limited pulpal or axial depth regardless of whether
end (or side) of bur is in dentin, caries, old restorative material, or air. C 0.2 mm DEJ
The dentinoenamel junction (DEJ) and the cementoenamel junction (CEJ)
are indicated in B. In A, initial depth is approximately two-thirds of 3mm
bur head length, or 2 mm, as related to prepared facial and lingual walls,
but is half the No. 245 bur head length, or 1.5 mm, as related to central
fissure location.
10
Fundamental Concepts of Enamel and
Dentin Adhesion
“Imagination is the beginning of creation…you imagine Waals). This would involve the chemical bond-
what you desire… ing to the inorganic component (hydroxyapa-
You will what you imagine and at last …you create
tite) or organic components (mainly type I col-
what you will.”
lagen) of tooth structure.
—GEORGE BERNARD SHAW
3. Diffusion adhesion: Interlocking between mo-
bile molecules, such as the adhesion of two pol-
Basic Concepts of Adhesion ymers through diffusion of polymer chain ends
across an interface. This would involve the pre-
cipitation of substances on the tooth surfaces to
Definitions
which resin monomers can bond mechanically
The word adhesion comes from the Latin adhaerere or chemically.
(‘to stick to’). Adhesion is defined as the state in 4. A combination of the previous three mecha-
which two surfaces are held together by interfacial nisms.
forces, which may consist of valence forces, or in-
terlocking forces or both (The American Society for Criteria for Optimal Adhesion
Testing and Materials [Specification D 907]).1
For good adhesion to take place, five fundamental at-
Adhesive is a material, frequently a viscous fluid
tributes which are required are illustrated in Fig. 10.1.
that joins two substrates together by solidifying, re-
sisting separation and transferring a load from one
surface to the other. Adhesive strength is the measure Indications for Adhesive Dentistry
of the load-bearing capacity of an adhesive joint.2
The availability of new scientific information on the
etiology, diagnosis, and treatment of carious lesions
Mechanisms of Dental Adhesion and the introduction of reliable adhesive restorative
materials have substantially reduced the need for ex-
In dentistry, bonding of resin-based materials to tooth
tensive tooth preparations. Adhesive techniques also
structure is a result of four possible mechanisms:3
allow more conservative tooth preparations, less reli-
1. Mechanical adhesion: Interlocking of the ad-
ance on macro-mechanical retention, and less remov-
hesive with irregularities in the surface of the
al of unsupported enamel. With improvements in
substrate, or adherend. This would involve the
materials, indications for resin-based materials have
penetration of adhesive resin and formation of
progressively shifted from the anterior segment only
resin tags within the tooth surface.
to posterior teeth as well.
2. Adsorption adhesion: Chemical bonding be-
Adhesive restorative techniques currently are used
tween the adhesive and the adherend; the forces
for the following indications:
involved may be primary valence forces (ionic
and covalent) or secondary valence forces (hy- 1. Restore class I, II, III, IV, V, and VI carious or
drogen bonds, dipole interaction, or van der traumatic defects
179
Dentin Adhesive
Hybrid Layer
T
U
B
U
L
E
13
Class III and IV
Direct Composite Restorations
A B
C D
Fig. 13.1 Direct composite restorations before and after. A and B, Class III. C and D, Class IV.
241
A B
C D
E F
G H
Fig. 13.14 Class IV tooth preparation and restoration. A, Extraoral view, minor traumatic fracture. B, Intraoral view.
C, Fractured enamel is roughened with a flame-shaped diamond instrument. D, The conservative preparation is etched,
while adjacent teeth are protected with Mylar strip. E–F, Contouring and polishing the composite. G, Intraoral view of the
completed restoration. H, Extraoral view.
17
Additional Conservative
Esthetic Procedures
303
A B
C D
Fig. 17.24 Macroabrasion. A, Outer surfaces of maxillary anterior teeth are unesthetic because of superficial enamel defects.
B and C, Removal of discoloration by abrasive surfacing and polishing procedures. D, Completed treatment revealing
conservative esthetic outcome.
A B
Fig. 17.29 No-prep veneers placed on maxillary anterior teeth. A, Before treatment. B, Immediately after placement of the
no-prep veneers. (Courtesy of Dr Patricia Pereira).
A B
C D
E F
G H
I J
K L
M N
O P
Q R
S T
U V
W X
19
Introduction to Amalgam Restorations
Amalgam
Dental amalgam is a metallic restorative material
composed of a mixture of silver-tin-copper alloy and
mercury. The unset mixture is pressed (condensed)
into a specifically prepared undercut tooth form and
contoured to restore the tooth’s form and function.
When the material hardens, the tooth is functional
again, restored with a silver-colored restoration
Fig. 19.1 Clinical example of an amalgam restoration.
(Fig. 19.1). Amalgam has been the subject of intense
(From Hatrick CD, Eakle WS, Bird WF: Dental Materials:
research and has been found to be safe and beneficial Clinical Applications for Dental Assistants and Dental
as a direct restorative material.1–8 Hygienists, ed 2, St. Louis, 2011, Saunders).
339
Box 19.2
Basic setting reaction of amalgam
Alloy particles of amalgam Dental amalgam
+ +
Mercury Unreacted alloy particles
Since the original mixture contains a large excess of
silver–tin alloy particles, only a minor portion of the
outside of the particles is consumed during the reaction
with mercury
Table 19.2
Phases of amalgam Clinical Notes
Silver–tin phase (Gamma) Ag3Sn
The tin-mercury gamma-2 phase (2) is the weakest
Silver–mercury phase 1 Ag2Hg3 phase in dental amalgam and is responsible for the cor-
Tin–mercury phase 2 Sn7-8Hg rosion process.
Copper–tin phase (Epsilon) Cu3Sn
Copper–tin phase (Eta) Cu6Sn5
II. High Copper Amalgam
High-copper amalgams set in a manner similar to
low-copper amalgams except that tin–mercury reac-
Box 19.3 tions are suppressed by the preferential formation of
Setting reaction of conventional low copper copper–tin phases instead.
amalgam alloy
i. High Copper Admixed Alloy
Ag3Sn + Hg Ag2Hg3 + Sn8Hg + Unreacted Ag3Sn
1 2 In high copper admixed alloys the reaction takes
place in two steps (see Box 19.4). There is elimina-
tion of gamma-2 phase, which is the weakest phase.
20
Class I and II
Amalgam Restorations
“Endurance is not just the ability to bear a hard thing, 3. Is in an area that will have heavy occlusal con-
but to turn it into glory”. tacts
—WILLIAM BARCLAY 4. Cannot be well isolated
5. Extends onto the root surface
Amalgam is used for the restoration of many carious 6. Will become a foundation for a full coverage res-
or fractured posterior teeth and in the replacement toration
of failed restorations. If properly placed, an amalgam 7. Is in a tooth that serves as an abutment for a re-
restoration provides many years of service.1–6 This movable partial denture.
chapter presents the techniques and procedures for
class I and II amalgam restorations (Fig. 20.1). Class Contraindications
I restorations restore defects on the occlusal surface
of posterior teeth, the occlusal thirds of the facial and Although amalgam has no specific contraindications
lingual surface of molars, and the lingual surfaces of for use in class I and II restorations, relative contrain-
maxillary anterior teeth. Class II restorations restore dications for use include:
defects that affect one or both of the proximal sur- 1. Esthetically prominent areas of posterior teeth.
faces of posterior teeth. 2. Small to moderate class I and II defects that can
be well isolated.
Indications
Amalgam is indicated for the restoration of a class I Advantages
and II defect when the defect: Primary advantages are the ease of use and the sim-
1. Is not in an area of the mouth where esthetics is plicity of the procedure. The placing and contour-
highly important ing of amalgam restorations are generally easier than
2. Is moderate to large those for composite restorations.7,8
A B
Fig. 20.1 Clinical examples of class I and II amalgam restorations. A, Class I amalgam in the occlusal surface of the first
molar. B, Class II amalgams in a premolar and molar.
361
b a
1.6
⬎1.6 mm
mm Correct Correct Incorrect
Contact
area
A B C
Fig. 20.5 The direction of the mesial and distal walls is influenced by the remaining thickness of the marginal ridge as
measured from the mesial or distal margin (a) to the proximal surface (i.e. imaginary projection of proximal surface) (b).
A, Mesial and distal walls should converge occlusally when the distance from a to b is greater than 1.6mm. B, When the
operator judges that the extension will leave only 1.6mm thickness (two diameters of No. 245 bur) of marginal ridge (i.e.
premolars) as illustrated here and in Fig.20.4B and C, the mesial and distal walls must diverge occlusally to conserve ridge-
supporting dentin. C, Extending the mesial or distal walls to a two-diameter limit without diverging the wall occlusally
undermines the marginal ridge enamel.
Step 3: Extension towards central fissure are extended, if necessary, to remove enamel under-
• The bur’s orientation and depth are maintained while mined by caries.21
extending along the central fissure toward the mesial
pit, following the DEJ (see Fig. 20.4E). Clinical Notes
• When the central fissure has minimal caries, one
pass through the fissure at the prescribed depth The strongest and ideal enamel margin should be com-
provides the desired minimal width to the isthmus. posed of full-length enamel rods attached to sound den-
tin, supported on the preparation side by shorter rods,
Ideally, the width of the isthmus should be just
also attached to sound dentin (Fig. 20.6).
wider than the diameter of the bur.
80° 100°
A B C D
Fig. 20.7 Enameloplasty. A, Developmental defect at terminal end of fissure. B, Fine-grit diamond stone in position to
remove the defect. C, Smooth surface after enameloplasty. D, The cavosurface angle should not exceed 100 degrees, and the
margin–amalgam angle should not be less than 80 degrees. Enamel external surface (e) before enameloplasty.
eloplasty is indicated. Enameloplasty (see chapter 9) pal floor) is best accomplished using a discoid-type
refers to eliminating the developmental fault by re- spoon excavator or a slowly revolving round carbide
moving it with the side of a flame-shaped diamond bur of appropriate size (Fig. 20.8).
stone, leaving a smooth surface (Fig. 20.7A through
C). The surface left by enameloplasty should meet the Clinical Notes
tooth preparation wall, preferably with a cavosurface
angle no greater than approximately 100 degrees; this • Using the largest instrument that fits the carious area is
would produce a distinct margin for amalgam of no safest because it is least likely to penetrate the tooth in
an uncontrolled manner.
less than 80 degrees (Fig. 20.7D).
• When removing infected dentin, the excavation should
be stopped when the tooth structure feels hard or firm
II. Final tooth Preparation (i.e. the same feel as sound dentin). This situation of-
ten occurs before all lightly stained or discolored den-
The final tooth preparation includes:
tin is removed.22
1. Removal of remaining defective enamel and • A sharp explorer or hand instrument is more reliable
infected dentin on the pulpal floor than a rotating bur for judging the adequacy of removal
Removal of the remaining infected dentin (i.e. car- of infected dentin. These instruments should be used ju-
diciously, however, in areas of possible pulpal exposure.
ies that extends pulpally from the established pul-
13-7
-14
Peripheral
seat
Section of
peripheral
seat
A B C D
Fig. 20.8 A and B, Removal of dentinal caries is accomplished with round burs (A) or spoon excavators (B). C and D, The
resistance form may be improved with a flat floor peripheral to the excavated area or areas.
21
Complex Amalgam Restorations
Indications
Complex posterior amalgam restorations should be
considered when large amounts of tooth structure are Fig. 21.1 Mesio-occluso-disto-lingual (MODL) complex
missing and when one or more cusps need capping amalgam tooth No.16.
(Fig. 21.1).1–4 Complex amalgams can be used as:
1. Definitive Final Restoration forces (see Chapter 24). When conventional reten-
tion features are not adequate because of insufficient
Usually, a weakened tooth is best restored with a remaining tooth structure, the retention form can be
properly designed indirect (usually cast) restoration enhanced by using pins, slots, and elective groove ex-
that prevents tooth fracture caused by mastication tensions (Fig. 21.2).
A B
Fig. 21.2 Maxillary second premolar weakened by extensive caries and by the small fracture line extending mesiodistally
on the center of the excavated dentinal wall. A, Minikin pins placed in the gingival floor improve resistance form after
amalgam has been placed. B, Restorations polished.
389
3.0 mm
2.0 mm 2.0 mm
2.0 mm
3.0 mm 3.0 mm
A B C
Table 21.1
The Thread Mate System (TMS) pins
Drill Pin length
Total pin
Color Pin diameter diameter extending
Name Illustration (not to scale) length
code (inches/mm)* (inches/ from dentin
(mm)
mm)* (mm)
Regular (standard) Gold 0.031/0.78 0.027/0.68 7.1 5.1
24
Class II Cast Metal Restorations
429
Inlay
4 Tooth
271 8862
169L
A B 0.8 mm 0.5 mm
C x
Fig. 24.1 A, Proposed outline form for disto-occlusal preparation in a maxillary premolar. B, Dimensions and configuration
of No. 271, No. 169L, and No. 8862 instruments. C, Conventional 4 degree divergence from line of draw (line xy).
271
271
w
Maxillary molar
z
Lingual
l
l
l
Facia
cia
gua
Fa
y
Lin
Mandibular molar
B C D
A 271
271
271
Bevel
E F G Correct H Incorrect
Fig. 24.2 A and B, Bur after punch cut to a depth of 1.5mm. C, For maxillary posterior teeth, the long axis of the bur should
parallel the long axis of the tooth crown (line yz). D, For molar and second premolar teeth of mandibular dentition, the long
axis of the bur should tilt slightly lingually to parallel the long axis of the tooth crown (line wx). E and F, Extending the
mesial wall, taking care to conserve dentin that supports marginal ridge (s). G, The marginal bevel can provide additional
extension. H, Improper extension that has weakened the marginal ridge.
A B
C D
Fig. 24.18 Maximum intercuspation interocclusal record made with polyvinyl siloxane bite registration paste. A, One
of many commercially available bite registration materials used in this technique. B, Using a cartridge dispenser and a
disposable automixing tip, the base and accelerator pastes are automatically mixed and applied to the prepared teeth,
their neighbors, and the opposing teeth. C, Have the patient close into maximum intercuspation position. Be sure that the
adjacent unprepared teeth are touching in their normal relationships. D, Remove the maximum intercuspation interocclusal
record carefully after it has set, and inspect it for completeness. Areas where the adjacent, unprepared teeth have penetrated
through paste should be seen.