Restorative Dentistry PDF
Restorative Dentistry PDF
Restorative Dentistry PDF
The right of Professor A. D. Walmsley, Professor Trevor Walsh, Professor F. J. Trevor Burke,
Dr Adrain C. Shortall, Dr Philip Lumley, Mr R. Hayes-Hall and Dr Iain A. Pretty to be identified
as authors of this work has been asserted by them in accordance with the Copyright, Designs and
Patents Act 1988.
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The Publisher
Printed in China
Contributors
vii
Preface
In 2002, the first edition of Restorative Dentistry was whilst it will be of interest to the junior undergraduate
launched on an unsuspecting dental profession. It was student first entering the clinic, it also contains areas of
an attempt to bring together all aspects of restorative interest to more senior students coming towards the end
dentistry and allow an understanding on how they inter- of their studies. Informal feedback from the first edition
acted with each other. Whilst the book was well received, has also shown that the book is useful to the young
there were some useful comments suggesting where the clinician who wishes to obtain an overview of restorative
content could be further improved. Therefore in this new dentistry. There are sections where the depth may extend
edition, many of the chapters have been updated and new beyond the undergraduate level but it is hoped that by
material has been included. We welcome the contribution doing so it provides an insight into the more varied work
from our new co-author, Iain Pretty. Iain is clinical lecturer that can be done when specialising in this area. There are
and honorary specialist registrar in restorative dentistry at many texts available which will allow the subject areas
Manchester Dental School. He has added a new chapter contained within the book to be followed up, and these are
on ‘Caries and Other Reasons for Restoring Teeth’ and listed in the further reading section at the end of the book.
also rewritten the introduction to the chapter on simple Once again I am indebted to the work of my co-authors
restoration of teeth. We welcome his contribution as it and I thank them for once again assisting me in the prepa-
provides a bridging link between the basic science and the ration of the material.The publishers have been immensely
clinical application of caries management. The provision helpful, and this second edition would not have been
of immediate and complete dentures was not included in possible without the constant help and encouragement of
the original edition and after feedback from our readers Mr Michael Parkinson and Dr Lulu Stader from Elsevier.
this has been added as a new section in the chapter ‘The Finally I am grateful for the many comments and other
Principles of Tooth Replacement’. All these new changes feedback that I have received from readers of the first
reflect the wide range of procedures and techniques that edition. It is my wish that the book acts as a guide to the
are involved in restorative dentistry. care of restorative patients and will lead to further reading
Covering the whole subject of restorative dentistry is a and debate around this important area of dentistry. Such
difficult task, and this book does not pretend that it can be feedback makes such projects worthwhile and on behalf of
done in a single text. However, what it does aim to do is all the authors I wish to extend a big thank you for taking
generate enthusiasm for this subject, which is at the the time to read and learn from Restorative Dentistry.
essential core of dentistry. It is hoped that it will introduce
readers to restorative dentistry and encourage them to A.D.W.
learn more by using it as an introductory text. Therefore, Birmingham 2007
ix
Acknowledgements
In the age of clinical photography, both digital and conven- Mr P. Murphy and Mr W. B. Hullah. All were involved
tional, the authors themselves took many of the photo- in the vast majority of the technical work seen in the text.
graphs displayed in the text. However, we would like to The authors would also like to thank the Conservation
express our gratitude to Mr M. Sharland and Miss M. Laboratory for assistance in the fixed restorations
Tipton of the School of Dentistry at the University of illustrated in the book.
Birmingham for their assistance in the reprinting and The authors wish to thank all our colleagues at the
duplication of many of the clinical photographs. There Universities of Sheffield, Birmingham and Manchester
are many examples of excellent technical work contained who gave helpful advice during preparation of the text.
within the book and it would be impossible to name every- Those colleagues who allowed us to include their clinical
body’s work, but the authors would like to thank in photographs have been acknowledged in the text.
particular Mr P. Browning, Mr S. Smith, Mr D. Spence,
xi
1 Introduction to restorative
dentistry
Keeping teeth is important for many functions, such as prior to the instigation of periodontal care. A patient with
eating and speech, whilst in our present society good irreversible pulpitis requires pain relief, which involves the
aesthetics are a high priority for the majority of people. use of endodontic care. The fracture of a tooth needs
A realistic outcome of dentistry must be a healthy com- temporising or, when occurring to the anterior teeth, a
fortable mouth with sound intact teeth. Dental care must temporary crown or other restoration is required. The list
also be designed to prevent any future problems and to of interactivity between the traditional disciplines is long
help to maintain this healthy environment. Restorative and shows the diverse nature of treatment planning that
dentistry involves the care of patients who require restora- will take place.
tion of the oral and dental tissues. This area of dentistry Prevention of damage to the tooth is a fundamental
crosses many of the traditional departments that exist part of restorative care. This will range from motivating
in teaching hospitals throughout the world and includes patients to clean their teeth effectively, to monitoring their
the disciplines of periodontology, operative dentistry, diet and giving appropriate advice. An increase in the
endodontics, and fixed and removable prosthodontics. demand for more advanced treatment reflects changes in
Other specialities, such as oral surgery and orthodontics, patient expectation, with a reluctance to accept tooth loss
are often involved in the planning of restorative care. and an increasing demand for advanced restorative treat-
Although the restoration of the oral tissues requires ment.There is often a need for comprehensive periodontal
technical skills, the clinician is intimately involved in the assessment and for advice and treatment of periodontal
decision-making process. A patient should receive inves- problems, which in the past have received insufficient
tigations that lead to a correct diagnosis. The clinician attention. Tooth wear is an increasing problem that causes
reaches the diagnosis after careful history-taking and sufferers concern, requiring careful assessment and some-
examination of the patient. Only then can a treatment plan times complex reconstructive techniques to avoid future
be drawn up which helps to achieve oral stability. The treatment and failure.
clinician should be an expert in all the disciplines that The restorative dentist is the leader of the dental team
make up restorative dentistry, but should also be able to and is responsible for the management of nursing and
integrate them in a sensible order and not as compart- hygiene care and laboratory support. Such a dentist must
mentalised procedures. be active in the field of clinical audit, establishing indices
The subject areas in the book are arranged in a tradi- of treatment need and measures to assess the outcome
tional order with periodontology at the start, and fixed of treatment procedures. Clinical governance is defined
and removable prosthodontics towards the end. The last as corporate accountability for clinical performance and
chapter hopes to show, with the use of case studies, that is about standards of quality. The restorative dentist
the progress of patient care often does not follow such should take part in continuing professional development
steps. Patients often require intervention with an imme- programmes and offer leadership to develop and improve
diate partial denture towards the beginning of treatment the quality of restorative dentistry care.
1
2 The healthy mouth
Lips and cheeks 3 and mandibular alveolar processes. Posteriorly, the ptery-
Alveolar processes 4 gomandibular raphe – a fibrous tissue band – stretches
Floor of the mouth and tongue 4 from the pterygoid process to the retromolar pad of the
Hard palate, soft palate and pharynx 5 mandible (Fig. 2.1). Anteriorly the mucous membrane is
The teeth 6 continuous with that of the lips.
The primary dentition 6 In the maxillary second molar region, the mucous
Permanent dentition 7 membrane of the cheeks is pierced by a duct – the parotid
Pulp dentine complex 7 duct – which ends as a papilla of variable size. Further
Periodontal tissues 8 down in the cheek, level with the occlusal surfaces of the
Gingiva 8 teeth, there is often a slightly raised, horizontal whitish
Junctional epithelium 9 band (Fig. 2.2). This is a band of keratinisation produced
Periodontal ligament 10 by chronic trauma from the teeth. While often barely
Cementum 10 noticeable, it can be pronounced and lead to confusion
Alveolar bone 10 with other, pathological, types of white lesion.
Posteriorly and in line with the corners of the mouth
there are often a small number of ectopic sebaceous glands.
These are of no significance but can be alarming when
The mouth is a highly specialised organ whose complex
present in large numbers. At times a large area may be
topographical anatomy reflects the diverse activities that it
covered by such sebaceous glands which appear as yellowish
must perform.
spots – Fordyce’s spots – and these can cause anxiety when
noticed for the first time.
LIPS AND CHEEKS
ALVEOLAR PROCESSES
Fig. 2.5 The dorsal surface of the tongue showing filiform and Fig. 2.6 The anterior hard palate showing the incisive papilla and
fungiform papillae; the filiform are the more numerous. rugae. 5
Restorative Dentistry
lie two small indentations, one on either side of the mid- beyond the gingival margin into the patient’s mouth.
line. These are the foveae palatini, where the ducts of two Variations in clinical crown length are often produced by
small clusters of salivary glands open into the mouth. different levels of gingival attachment to the tooth and are
The soft palate is covered with stratified squamous seen in patients suffering from gingival recession and hence
epithelium and divides the oropharynx from the naso- showing increased clinical crown length. Short clinical
pharynx. It terminates distally in a short muscular projec- crowns are seen in teeth that have worn excessively,
tion, the uvula, and by its contact with the posterior wall commonly due to bruxism, or where teeth have been worn
of the pharynx regulates the flow of air through the mouth down by attrition.
and nose when breathing and speaking. At this point on Incisors and canines have four axial surfaces converging
the posterior wall of the pharynx, a functional thickening in an incisal edge. Premolars and molars have five surfaces,
of the superior constrictor muscle, called the ridge of the incisal edge being replaced by an occlusal surface.
Passavant, aids production of an airtight seal. The surface of the crown shows many elevations and
Laterally the side of the pharynx is marked by two depressions which make up the typical appearance of the
arches. The anterior is produced by the presence of the tooth. The following terms are used in the description of
palatoglossus muscle. It is separated by the pharyngeal crown anatomy:
tonsil from the distal arch, which is formed by the palato-
Cusp: an elevation or mound on the occlusal surface.
pharyngeus muscle (Fig. 2.7). The pharyngeal tonsil is a
collection of lymph tissue and in young patients is Cingulum: the lingual convex bulge on an anterior tooth.
frequently red and swollen in response to infection. In
Tubercle: a small elevation on some part of the crown
later life, it atrophies and even shows calcification, which
produced by an extra formation of enamel and dentine.
can be a source of diagnostic confusion on panoramic
These are quite frequently seen buccally on deciduous
radiographs. The pharyngeal tonsil is part of a ring of
first molars (the tubercle of Zuckerkandl) and lingually on
lymphoid tissue, the other parts of which are the lingual
upper first molars (the cusp of Carabelli).
tonsil, found on the posterior third of the tongue, and the
adenoids, a collection of lymph tissue found in the midline Ridge: a linear elevation on the surface of a tooth. A good
of the posterior wall of the nasopharynx. example is the marginal ridge found on the mesial and
distal surfaces of molars and premolars.
Fissure: an irregular linear depression in the tooth
THE TEETH
surface. A pit is a small pinpoint depression.
A tooth may be divided into crown and root, the crown Developmental groove: a developmental deformity in
being covered by enamel and the root by cementum. The the crown and/or root of a tooth. This type of defect will
two surfaces meet at the cement–enamel junction which encourage the formation of a periodontal pocket, particu-
is visible as the cervical line on the neck of the tooth. In larly when it involves the root, because dental plaque will
the healthy mouth of a young adult, the level of gingival collect there undisturbed. Grooves are sometimes seen on
attachment will be coronal to the cervical line. The permanent upper lateral incisors, especially on palatal
anatomical crown ends at the cervical line, in contrast to surfaces.
the clinical crown which is the amount of tooth protruding
Mamelon: any one of the three rounded protuberances
found on the incisal edges of recently erupted anterior
teeth. Mamelons wear away quickly, usually within two
years of eruption.
PERIODONTAL TISSUES
Gingiva
The gingiva line the external surface of the periodontium
(Fig. 2.12, Box 2.3). The gingival tissue runs from the
mucogingival line, which marks the boundary with the
non-keratinised buccal mucosa, and covers the coronal
aspect of the alveolar process. On the palatal aspect, the
mucogingival line is absent as the gingiva here is con-
tinuous with the keratinised, non-mobile palatal mucosa.
Fig. 2.9 Radiograph of periradicular lesion associated with a The gingiva ends at the cervix of each tooth, surrounds
8 lateral canal. it and attaches to it by a ring of specialised epithelial tissue
2 / The healthy mouth
Alveolar bone
Cementum ing the external surface of the gingiva, the crevicular epithe-
lium lining the gingival crevice, and the non- keratinised
junctional epithelium (Fig. 2.13).The crevicular epithelium
Fig. 2.11 The periodontal tissues.
resembles the oral gingiva coronally and the junctional
epithelium apically. The degree of keratinisation varies,
– the junctional epithelium. This epithelial attachment therefore, according to relationship to the tooth. Under-
provides continuity of the epithelial lining of the oral cavity neath the gingiva is the dense gingival connective tissue.
with the surface of the teeth.
Healthy gingiva is described as ‘salmon’ or ‘coral pink’. It
Junctional epithelium
may be pigmented, which reflects the ethnic origin of the
subject. The gingiva is firm in consistency and firmly The junctional epithelium (JE) adjacent to the tooth is that
attached to the underlying alveolar bone. The surface of part of the gingiva which attaches the connective tissue to
gingiva is keratinised and may exhibit an orange peel the tooth surface (Fig. 2.14). It forms a band 2–3 mm
appearance, called ‘stippling’.The width of attached gingiva
can vary dramatically between patients and within an
Epithelial attachment
individual’s mouth, from as little as 1 mm to over 10 mm.
Figure 2.12 shows healthy gingiva. The free gingival Junctional epithelium
margin covers the cemento-enamel junction (CEJ) and
the gingival papillae fill the embrasures. A shallow linear Oral gingiva
Enamel
depression, the gingival groove, can be observed in some Circular fibres of
areas, distinguishing the free gingival margin from the gingival tissues
attached gingiva. Microscopically, gingiva consists of strati-
Free gingiva
fied squamous epithelium supported by a thin layer of
dense fibrous connective tissue (Box 2.4). The gingival Blood vessels
epithelium may be divided into the oral epithelium cover- Dentine
Alveolar bone
Periodontal ligament Attached gingiva
principal fibres
Mucogingival junction
Cementum
Lining mucosa
Fig. 2.13 The dento-gingival area.
Hemidesmosomes
Tonofibrils
Enamel
Lamina densa
Desmosome
11
3 Examination of the
patient and treatment
planning
Overview 13 structured but which does not necessarily lead the patient.
Phase 1: history and examination 13 A medical history is taken at this stage in order to ascertain
Reason for attendance 14 whether the patient has any conditions of relevance to the
Complains of 14 dental treatment. Certain medical conditions may affect
History of present complaint 14 the management of the patient and these should be
Medical history 15 identified when the treatment plan is being drawn up.
Dental history 16 Once this is completed, the clinical examination, which
Personal/social history 16 includes both the extraoral and intraoral examinations, can
Phase 2: examination 17 be started.The extraoral examination includes observation
Extraoral 17 and investigation of the patient and structures around the
Intraoral 17 mouth. The intraoral examination includes the soft and
Special investigations 20 hard tissues and a restorative assessment.
Phase 3: diagnosis 21 This chapter aims to help the reader undertake a good
Treatment plan 21 history and examination with guidance to the formulation
Signature 21 of a treatment plan. The plan should involve a holistic
Summary 22 approach to what is required. It is important that the
patient’s mouth is not seen merely as a long list of items
each of which requires completion before the next one can
be started. Furthermore, the patient should not be classed
OVERVIEW as a ‘perio’ or ‘cons’ patient. All dental disciplines, from
prosthetics to oral surgery, may need to be considered and
A patient attending for treatment of a restorative nature integrated into the patient’s subsequent care.
may present for a variety of reasons. Many patients will be
returning for their regular half yearly or annual recall.
Others will be attending with a problem, which may be PHASE 1: HISTORY AND EXAMINATION
related to their gums, the hard tissues of the teeth or to the
restorative work that has been undertaken on previous Greeting patients in a friendly manner during the initial
visits. As the clinician you possess the skills to intervene introductions goes a long way to establishing personal
and rectify problems and to undertake requests for dental contact and allows them to familiarise themselves with
treatment. Patients may present with a problem or a both yourself and the surroundings. When seating patients
clinical situation which is not immediately apparent to in the chair, the ideal arrangement for conducting the
them but which requires intervention. It cannot be history is to be facing them while maintaining eye contact.
overstressed that the outcome of this first visit is vital to A simple, but effective and necessary, method to initiate
the success of any subsequent treatment undertaken. the proceedings is to confirm that the patient’s details are
This success is built upon careful history-taking coupled correct. Talking about the weather, travel, holidays, news
with a logical progression to diagnosis of the problem that topics, sports and the like will quickly initiate a two-way
has been presented to you. Each stage follows on from the discussion and often relaxes the patient. A few minutes
preceding one. A description of the patient’s complaint spent in this way can often gain a patient’s confidence and
should be carefully recorded in the notes. This written establish a rapport that will bring rewards in the latter
record is based on accurate questioning which is carefully treatment stages.
13
Restorative Dentistry
14
3 / Examination of the patient and treatment planning
previously. Problems related to denture-wearing may Listen to and observe other clinicians and always be
include a history of previous denture-wearing. This should prepared for the unexpected. History-taking is an art form
include the age of the denture, how many have been and it has only been possible to provide the basic building
constructed in the past and how successful these previous bricks in this account, but the clinician should always be
dentures were. Any alteration of shade or appearance of prepared to learn and be aware of the patient’s presenting
the teeth that has been noted by the patient is recorded. symptoms.
Wear of the teeth may only have been noticed at a recent
examination and brought to the patient’s attention by his
Medical history
or her own dentist. Patients will first become aware of loss
of tooth substance when their teeth are starting to become This is an essential part of any examination and will have
smaller in length. Tooth wear may be associated with an important bearing on all aspects of the diagnosis and
sensitivity of the teeth and this symptom may highlight an subsequent treatment planning. Any relevant medical history
erosive diet or the possibility of parafunction during sleep. is required, for the protection of a patient, other patients
It is impossible to cover all the different histories that and the dental team. A simple way to avoid missing any
may arise. No history is the same and, often, histories taken relevant aspects of a patient’s history is to use a medical
of the same patient by different dentists are different. history sheet, an example of which is given in Box 3.1.
Box 3.1 Example of a medical history questionnaire. The form is designed as an aide-memoire and it is essential that
relevant details of positive medical history information are sought and recorded.
FOR COMPLETION BY THE CLINICIAN
Are you: Yes No Details
1. Receiving medical or hospital treatment at present?
2. Taking any tablets, medicines or any other substance, Please list on separate page
e.g. inhalers?
3. Allergic to any tablets, medicines or any other
substance, e.g. penicillin/latex (rubber)?
4. Pregnant (if appropriate)?
Have you:
5. Ever had a heart murmur, rheumatic fever (e.g. chorea,
St Vitus’ dance) or any other problem with your heart?
6. Ever had raised blood pressure, angina, a heart attack
or thrombosis, e.g. CVA, DVT?
7. Ever had hepatitis, jaundice or been diagnosed with
HIV disease?
8. Ever had any chest problems, e.g. asthma/bronchitis
or tuberculosis?
9. Ever had an operation or illness treated in hospital?
10. Been diagnosed with epilepsy?
11. Been diagnosed with diabetes?
12. A family member or close relative with
Creutzfeldt–Jakob disease (CJD)?
13. Ever had prolonged bleeding following a tooth
extraction or other surgery?
14. Ever had a problem with local or general anaesthetic
15. Any other problems that may be relevant?
15
Restorative Dentistry
The first questions ask patients whether they are receiving patients. Diabetics will range from those whose diabetes
medical treatment, and this includes medicines, tablets or is diet- or tablet-controlled to those who are insulin-
injections. It is often useful to ask patients to bring any dependent. Dental procedures may be influenced accord-
medication they are taking along to the next visit, so that ing to when they last ate. Their diabetes may also have
the precise drugs and dosages can be identified. Some direct relevance to their periodontal status (see p. 29).
aspects highlighted in the form may need to be clarified by Transmissible spongiform encephalopathies are rare, fatal
contacting the patient’s doctor. Many patients are taking degenerative brain diseases which may affect humans. Any
a concoction of drugs and an up-to-date version of the patient with such a disease (e.g. Creutzfeldt–Jakob disease)
British National Formulary (BNF) will help to identify their would require the clinician to undertake the highest standard
use and, more importantly, any known interactions.This is of cross-infection control with the use of disposable instru-
important for dental procedures, which often involve the mentation. Likewise, serious problems with bleeding must
use of drugs, ranging from local anaesthetics to sedatives. be recognised and will necessitate contact with the patient’s
Penicillin and related drugs are commonly given prophy- medical practitioner. Patients are also asked whether they
lactically or to treat infections, and allergies to them should have had problems with local or general anaesthesia and
be recorded to avoid the occurrence of any anaphylactic any positive responses are recorded.
reactions. Furthermore, the increased use of latex gloves The final question of the medical history is to enquire
and rubber dam for operative and endodontic procedures whether there is any other health matter or other problems
has led to an increased incidence of contact dermatitis. that are of relevance and that have not been mentioned
Such potential allergic reactions to rubber should be noted. earlier. Any relevant history may be discussed with the
Females of child-bearing age are asked if they are pregnant. patient’s GP, either by letter or by telephone, who will
The next set of questions cover the cardiac and respira- always be happy to help and give advice.
tory systems together with other important conditions of A patient’s medical history is not static and it is prudent
immediate relevance to dentistry. Patients who have had the to ensure that changes are regularly checked and updated
following conditions may require some form of antibiotic and that this is clearly recorded as a dated entry in the
cover: rheumatic fever, chorea, heart defect, heart murmur patient’s clinical notes. It is useful to have an agreed
or heart valve replacement. Up-to-date antibiotic regimes marker on the patient’s notes (such as a red sticker) that
are covered in the BNF. The need for antibiotic cover may immediately flags up, at a glance, an important aspect of
well influence the subsequent treatment planning. For the medical history to other clinicians who may be involved
instance, lengthy treatment plans over many visits may not with the patient’s treatment. A list of those conditions
be feasible and simplification may well be required. Patients which justify such a marker is given in Box 3.2.
who have suffered angina or heart attacks must be closely A well-structured medical history, completed, signed
monitored and their appropriate medication should be on and dated and subsequently updated on a regular basis, is
hand if problems arise. Patients with raised blood pressure a key part of the essential duty of care owed by a dentist to
may be on medication that will interact with local his or her patient.
anaesthetics and other drugs. The risk of cross-infection is
high in patients suffering from hepatitis or those with a
Dental history
history of jaundice. Simple questioning will reveal whether
it was hepatitis A or the more infectious B, C etc. condi- Careful questioning at this stage can quickly reveal the
tions. Details of other infectious diseases such as HIV are patient’s approach to dentistry. Such questioning includes
checked at this stage. the frequency of visits to the dentist and details of the last
Patients may also reveal relevant medical details when sequence of treatment. This may often reveal differing
asked about operations and other illnesses they may have attitudes to dentistry that will assist in later planning. Any
had. Chest conditions may limit the tolerance of a patient difficulties patients have previously experienced with
to certain procedures of long duration, and consideration dental treatment may well influence your treatment plan.
should be given to this in the treatment plan. Asthma is a Also at this stage, a patient presenting with complex dental
condition that is rising in prevalence. Patients may be problems may express a reluctance to undertake a series of
taking corticosteroids with inhalers and these should be lengthy visits.
present in case patients become distressed and suffer an
asthma attack during treatment. Tuberculosis (TB) is an
Personal/social history
infectious disease that is increasing in prevalence. Patients
identified as suffering from TB will often require special The clinician can gain an insight into the patient’s dietary
cross-infection control procedures, and contact must be habits and approach to oral hygiene measures by careful
made with their doctor. Epileptics are identified and the questioning. The frequency, amount and diversity of sugar
clinician should be prepared for an attack. Advanced intake are recorded. Any erosive eating or drinking
restorative procedures such as bridges and removable preferences need to be identified and noted for further
16 partial dentures may need careful planning with such discussion. This requires some sensible questioning as
3 / Examination of the patient and treatment planning
Box 3.2 Conditions that justify a hazard sticker attached to the front of the hospital record
• Cardiac surgery • Systemic steroid therapy
• Pacemaker • Intravenous drug user
• Cardiac murmur (other than functional) • Hepatitis B/C
• Organ transplant • HIV/AIDS
• Rheumatic fever • Chronic renal failure
• Infective endocarditis • Severe asthma
• Hypertension • Active tuberculosis
• Warfarin therapy • Epilepsy
• Bleeding disorder • Diabetes
• Drug allergies • History of head and neck radiotherapy
patients may not attach importance to such details in their be recorded. An assessment is made on the vertical
diet, but they may be highly relevant to their dental condi- dimension as to whether it is normal or if there is over-
tion. For instance, many patients link fruit consumption closure. Gross skeletal discrepancies in the relationship of
with health and are therefore unlikely to associate this the mandible to the maxilla are recorded during the exami-
with their dental problems. An initial idea of a patient’s nation. Other problems such as swellings or generalised
oral hygiene can be obtained from the frequency of tooth- asymmetry to the overall face are noted. Muscular hyper-
brushing and the use of interdental aids such as dental trophy may be evident and is a useful empirical indicator
floss or brushes. If the patient wears dentures, the prosthetic of parafunctional activity. The muscles of mastication
hygiene regime should be recorded. should be palpated to check for any tenderness. Assess-
Smoking and alcohol intake should be enquired about ment of the temporomandibular joints is made by palpa-
and, where necessary, as a health professional, it is your tion, looking for the presence of clicks and observing any
duty to advise on such matters. Smoking habits will have a unnatural movements on opening and closing of the jaw.
direct influence on periodontal treatment; for example, Deviation may relate to a number of conditions or may be
wound healing is delayed following surgery in smokers. a normal observation. The submandibular lymph nodes
This may well, once again, dictate the level of dental care are palpated. Good access to the lymph nodes is obtained
that is given to the patient. by asking the patient to bring the head forwards and drop
Enquiry into a patient’s personal/social history is often the chin. The lymph nodes can then be located by drag-
covered in a superficial manner, but with careful question- ging them over the lower border of the mandible and feeling
ing, a patient’s attitude towards and motivation in respect their subsequent recoil to the soft tissue. Any palpable
of dentistry will be revealed and these may provide clues nodes may be indicative of a recent infection.
to the presenting problem that may not have been imme-
diately apparent in the earlier history-taking. Furthermore,
Intraoral
the subsequent treatment process may be influenced by
the patient’s ability to cope with the treatment. This could Soft tissues
affect your decision on whether to embark on a short
A thorough inspection should be made of the surfaces of
simple course of visits or a complicated treatment plan of
the tongue, palate, floor of mouth, buccal and lingual
an advanced nature.
mucosa (including the lips), looking for any abnormalities
such as ulcers, erosive areas and colour changes of the
mucosa. The cheeks and tongue may show markings and
PHASE 2: EXAMINATION
indentations which may be an indication of tongue or
cheek biting. This will be the result of some form of para-
During the examination process, only what is seen is
functional activity of the teeth.
recorded and any formal diagnosis should be left until the
end. It is easy to become diverted and go immediately to
the patient’s problem. The whole mouth should be Periodontal assessment
examined in a systematic manner before the main area of
An examination of the periodontal tissues should be made.
complaint is considered.
The aim is to provide a basic screening of the tissues and
to obtain an indication of the treatment requirements of
Extraoral the patient.
A general impression of the overall appearance of the Basic periodontal examination (BPE). This is
patient is a useful indicator and any abnormalities should performed clinically using the CPITN (community 17
Restorative Dentistry
18
3 / Examination of the patient and treatment planning
4 1 6 4 1 6
DRESSER BPE
STAFF:
18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28
TREAT.
EXAM
EXAM RF PC
TREAT.
48 47 46 45 44 43 42 41 31 32 33 34 35 36 37 38
Fig. 3.3 Dental chart including basic periodontal examination (BPE) scores.
alone, but may also be taking place on buccal and palatal of cause, and allows monitoring of the effectiveness of
surfaces. Recording tooth surface loss is a difficult proce- preventive measures, even when the aetiology is obscure.
dure and a number of indices have been used. One of the
more commonly accepted scoring systems is the Smith Tooth fracture. Any trauma or fracture of the teeth is
and Knight index, which is shown in Table 3.3. This index recorded, together with an indication of any looseness of
records the degree of wear on all tooth surfaces, regardless the tooth in its socket.
Table 3.3 The Smith and Knight index. This requires the surface of each tooth to be given a score between 0 and 4
according to its appearance
19
Restorative Dentistry
Discoloration. Alteration in the colour or any other posterior to the intercuspal position. Interferences are
similar problems related to the natural teeth are noted. abnormal contacts that interfere with the smooth
Any alteration to the shade and appearance of any fixed movements of the mandible and may be the cause of tooth
restorations is entered into the notes. fracture or cementation failure of a crown etc., or may lead
to tooth mobility. Such deviations from the normal
movements are recorded in the notes.
Removable prosthodontic assessment
The following information gives a simple overview of
Special investigations
any removable prosthesis that the patient is wearing. It
can also be modified for an assessment of the load- Having reached this part of the examination, the clinician
bearing structures prior to the decision to construct a will have identified any problems that may be present. If
prosthesis. the patient has a specific problem then it will have become
evident during the examination. The clinician may now
Partially dentate/edentulous. The nature of the support wish to examine in more detail the area of complaint. It is
given to the prosthesis is recorded. This may be simply useful to make a provisional diagnosis of the condition
recorded as either tooth or mucosa, or a combination of prior to these tests. This hypothesis will then be either
the two, i.e. tooth/mucosa. This latter situation is encoun- proved or disproved during these stages leading to a final
tered with the free end saddle. diagnosis. However, to confirm such a judgement, further
Edentulous areas. The quality of the mucosa and bone investigations must be undertaken, such as those
support is evaluated. The ridge may be palpated to deter- described below.
mine its firmness. Any bony irregularities or structures
that may interfere with the design of the removable partial Vitality testing of the pulp
denture (RPD) should be examined.
Vitality of the tooth may be tested using either electrical or
Condition of existing dentures. If existing dentures are thermal stimulation. Electrical testing will require a small
present they should be examined and an assessment made charge to be applied to the tooth. The charge is generated
of their stability, the base extension and the retention of by a machine and the patient becomes part of the circuit
the prosthesis. when the tip is applied to the tooth. Good electrical
contact is achieved by the use of prophylactic paste. The
present machines do not require clinician contact, as the
Static/dynamic occlusion of teeth/prosthesis
use of rubber gloves often prevents a good electrical circuit
All teeth are examined for tilting rotation, overeruption, being formed. Thermal stimulation may be through either
malalignment, wear faceting and burnished areas on cold or heat, but cold stimulation is preferred.This is done
restorations.The patient is asked to close the teeth together using an ice stick or a pledget of cotton wool soaked in
and an assessment is made of the occlusal relationship.The ethyl chloride, which will give a quick response. However,
occlusion is assessed as canine protected or group func- a more intense cold stimulus can be provided by the use of
tion, and any non-working side contacts are noted. dry ice (CO2).
The intercuspal position is the relation of the mandible
to the maxillae when the teeth are together in maximum
Study casts
intercuspation. The majority of patients have a habitual
intercuspal position (i.e. a comfortable position that they Study casts of the teeth may be required and these may
close into without any guidance). be poured from preliminary alginate impressions taken
Lateral excursions are guided commonly by the canine in a stock try. A more accurate determination of the
and the premolar teeth. In canine guidance, the posterior occlusal relationship will require alginate impressions in
teeth will disclude in lateral excursions. In group function, individual trays made from the preliminary casts.
a group of teeth, such as the canines and premolar teeth, Registration of the occlusion together with a face bow
are contacting on the working side (i.e. the side to which recording may be necessary. This will be incorporated
the mandible moves). In protrusive movements, the in the provisional treatment plan prior to the finalised
anterior teeth move over each other with the posterior treatment.
teeth discluding. However, in tooth wear, the posterior
teeth may be in function due to excessive wear of the
Other tests
anterior teeth. The retruded contact position of the
mandible is where it is in its furthest distal position when These include the use of a diet sheet to investigate for high
contacting the upper teeth. Generally the patient can be caries/erosive nature. Any suspicious alteration to the
guided into this position, which is usually 1–2 mm further mucosa within the mouth will require the opinion of an
20
3 / Examination of the patient and treatment planning
TREATMENT PLAN
oral medicine or oral surgery specialist, who may wish to
obtain a biopsy of the area to confirm the diagnosis from
Once a firm diagnosis has been made, a treatment plan is
a histological specimen. This may also include blood tests
drawn up which is aimed at correcting the patient’s
if an underlying disorder is suspected.
presenting problem. This plan may be provisional or final
and should not be changed without good reason. It is often
Radiographic examination tempting, if one has not seen the patient at the examina-
tion stage, to change another clinician’s plan. If this is to be
The most common special investigation performed is the
done, any changes should only be made following discus-
radiographic examination. This will provide further
sion with the person who instigated the treatment. A
evidence that may confirm your provisional diagnosis.
treatment plan should be drawn up with the patient’s
The most useful technique is long cone radiography, in
consent and should take into consideration the patient’s
order to produce bite wings or periapical views of the hard
commitment to the work involved and the number of visits
dental tissues together with the immediate supporting
required to complete it.
tissues. Bite wings are indicated where there are multiple
contacts between the teeth and they are the only reliable
method for detecting approximal caries. They should be
SIGNATURE
taken on a 2-yearly basis unless there are indications of
a rapid carious process taking place, in which case they
A patient’s history is a legal document and should be
should be taken more frequently. If the patient is new to
signed clearly. Although written records are still kept, there
your practice then a set of bite wings should be taken.
is a trend towards the computerisation of data. This can
Information gained from such radiographs includes the
still be held as a legal document but there must be safe-
presence of caries (new or recurrent), bone levels around
guards regarding access to the information, and back-up
the teeth and the marginal contour of the restorations.
files need to be made in case of disk failure.
When there is apical involvement, as indicated by the
history, a long cone periapical is taken. This will provide
information over and above that obtained from the bite
Box 3.3 Aide-Memoire*
wing radiograph and will reveal any problems related to
the pulpal chamber, such as internal resorption, status of Referred by: Reason for referral:
previous root canal therapy (if present) or the surrounding
periapical tissues (i.e. bone loss due to periapical infection Date of referral: Date seen:
or cyst formation). It will also provide more detailed
1. Reason for attendance RFA
information relating to alveolar bone loss between the
2. Complains of CO
teeth or furcation involvement.
3. History of present complaint HPC
Where indicated, further radiographic examination
may be required to examine larger structures, e.g. ortho- 4. Medical history MH
pantomographs (OPG) for the mandible, occipital mental 5. Dental history DH
(OM) for the sinuses and temporomandibular joint (TMJ) 6. Personal/social history PH/SH
views.Where there are areas of concern that are not imme- 7. Examination
diately apparent, the views of a consultant radiologist (a) Extraoral EO
(b) Intraoral IO
should be sought.
Soft tissue exam
Hard tissue exam
Periodontal assessment
PHASE 3: DIAGNOSIS BPE screen
Assessment of edentulous areas
Assessment of removeable/fixed appliances
You are now in a position to formulate a definitive diagnosis
Static/dynamic occlusion of teeth/prosthesis
concerning the nature of the problem. A brief summary of
8. Special investigations
the findings should be written down and the diagnosis
9. Diagnosis
stated. Many individuals find this statement difficult to
articulate and it is often left open. The diagnosis must be 10. Treatment plan
stated in the notes. For example, it may be caries caused 11. Signature
by high sugar consumption, or chronic adult periodontitis; *An 11-point structure to history-taking, examination, diagnosis
there may be reversible or irreversible pulpitis. It is impor- and treatment planning with appropriate abbreviations (these may
differ between teaching institutions but the general approach will
tant to be precise and to write down your diagnosis clearly. be similar).
It can be modified in the light of further contact with the
patient but it is the key to your treatment planning.
21
Restorative Dentistry
22
4 Inflammatory periodontal
diseases
GINGIVITIS
Types of gingivitis
There are a number of different types of gingivitis includ-
ing both acute and chronic forms.
Fig. 4.2 A burn produced by applying aspirin directly to the soft Fig. 4.4 Acute allergic reaction in the marginal gingiva produced
24 tissues. by a reaction to a toothpaste.
4 / Inflammatory periodontal diseases
HIV-associated gingivitis
Recently an acute form of gingivitis has been described
that is seen in sufferers of acquired immune deficiency
syndrome (AIDS); this has been categorised as a definitive
form of gingivitis. It is most probable that this condition is
only an exaggerated or unusual response to dental plaque
due to the immune deficits that occur in these patients.
The commonest symptom is an intense marginal
gingivitis in a patient who has been diagnosed as infected Fig. 4.6 Acute herpetic gingivostomatitis: vesicles can be seen
with the human immunodeficiency virus (HIV). In the scattered throughout the oral mucosa. 25
Restorative Dentistry
Fig. 4.8 A patient with adult periodontitis showing large Fig. 4.9 A young patient with prepubertal periodontitis. A lower
amounts of dental plaque deposits but a low-grade inflammatory incisor has already fallen out.
response.
These are very varied but will always include the following • Papillon–Lefèvre syndrome
features: • Insulin-dependent diabetes
• Primary or acquired immunodeficiency
• Loss of attachment, which will present as periodontal • Leukaemias
pocketing or gingival recession, or a combination of • Hypophosphatasia
both • Histiocytosis X
• Bone resorption • Neutropenia
• Tooth mobility • Chediak–Higashi syndrome
• Agranulocytosis
• Drifting
• Suppuration from the active sites
HIV-associated periodontitis
It is unusual for a periodontal abscess to occur in the
Periodontitis associated with patients whose immune absence of severe periodontitis, although it may be initiated
systems are compromised by HIV infection may show by acute trauma. The precipitating causes are not clearly
unusual features (Box 4.6). The marginal gingivitis may understood and it is quite possible that they may vary from
be intense and sometimes the overlying soft tissue will patient to patient. The main causes are shown in Box 4.7.
be necrotic, exposing marginal bone around the tooth. The abscess may present as a localised swelling with
Pocketing, when present, will be deeper than expected. erythema of the overlying mucosa. The tooth may be
There is often an associated candidal infection. tender to biting or percussion, and the patient may
complain of throbbing which is relieved by pressure. The
swelling is frequently, but not invariably, fluctuant. There
Acute periodontal abscess
may be systemic symptoms, such as lymphadenitis of the
A periodontal abscess can occur with any type of local lymph nodes, as well as raised temperature. This is
periodontitis and is therefore not a type of periodontitis more common when the condition is acute, but once
but a particular feature or symptom. A periodontal abscess drainage has been achieved the abscess becomes chronic
forms when pus collects in the connective tissue wall of with a lessening of symptoms.
a pocket. It is important to distinguish this from a peri-
radicular abscess caused by an infection emanating from
the pulp, and in order to emphasise this distinction the
term ‘lateral periodontal abscess’ is often used. The differ- Box 4.7 Commoner factors associated with an acute
ential diagnosis may be made based on the history, clinical periodontal abscess
examination, vitality tests and appropriate radiographs. • Entry of organisms into the connective tissues adjacent
to the periodontal pocket, which has been shown to
occur in deep periodontal lesions
Box 4.6 Manifestations of HIV periodontitis • The forcing of plaque, calculus and other irritant debris
through the pocket lining during scaling and root
• Inflammatory periodontal disease debridement procedures
• HIV-associated gingivitis • Impaction of foreign bodies into the periodontal pocket.
• Acute necrotising ulcerative gingivitis This is often quoted as a cause of the problem but the
• Acute necrotising ulcerative periodontitis authors have never seen a periodontal abscess
• Acute necrotising stomatitis associated with this type of damage
• Gingival ulceration associated with: • Blockage of a pocket with obstruction of drainage.
– herpes simplex Although this is a possible cause, the majority of
– herpes zoster abscesses seen are draining through the pocket on
– human cytomegalovirus presentation
– non-Hodgkin’s lymphoma • Reduction of host resistance as seen in some conditions
– Kaposi’s sarcoma such as diabetes, which are associated with frequent
– neutropenia periodontal abscesses
30
5 Management of
inflammatory periodontal
diseases
(a) (b)
Fig. 5.1 (a) A patient with gingivitis before treatment: note the red, swollen gingiva. (b) The same patient after treatment. The gingival
32 tissues have shrunk, reducing the swelling. The gingiva are now pink with light stippling.
5 / Management of inflammatory periodontal diseases
hygiene difficult, the use of chemical methods of plaque coping with the HIV infection. The oral lesions should
control is indicated. always be reported to the consulting physician as they may
indicate the development of AIDS in an HIV sufferer. The
oral lesions should be sampled with a smear and checked
Acute hypersensitivity reactions
for candidal infection, as this is often present and may
Hypersensitivity reactions to the constituents of tooth- cause an acute form of gingivitis. Assuming that no unusual
pastes and occasionally cosmetics are sometimes seen as organisms are found, reinforcing the oral hygiene, together
an ‘allergic gingivitis’. An important principle in the treat- with chemical plaque control by using a 0.2% chlorhexidine
ment of these patients is not to expose them to further gluconate mouth rinse, will help in controlling the problem.
chemicals to which they may react. The urge to use a
chemical anti-plaque agent should be avoided and the
Acute herpetic gingivostomatitis
patient should be reassured and the toothpaste changed to
allow healing to occur. Oral signs of acute herpetic gingivostomatitis include sore-
ness of the oral mucosa, with formation of small vesicles
that rapidly burst producing ulcers surrounded by a bright
Acute necrotising ulcerative gingivitis (ANUG)
red halo. There is often a concomitant marginal herpetic
This acute gingivitis is characterised by necrotising inter- gingivitis and also signs of systemic involvement, including
dental ulcers which spread rapidly to the other areas of the malaise, fever and lymphadenitis. The most important
gingiva. The management of sufferers of ANUG is based aspect of management is to maintain fluid balance by
on recognition of the predisposing factors. In view of encouraging fluid intake. Food should be soft and cold
the relationship between ANUG and stress, and the need items may be soothing. This is one of the few occasions
for appropriate home care to prevent recurrence, a very when the clinician may recommend ice-cream with no
careful explanation of the problem together with possible sense of guilt. Bed rest should also be advised.
treatment should be provided to the patient. Advice The use of a 0.2% chlorhexidine gluconate mouth rinse
should be given on the avoidance of smoking and the need will help to reduce the severity of secondary infection in
for an adequate diet. The initial acute phase should be the oral lesions. In the older patient, the use of benzocaine
treated by careful debridement of the lesions with the lozenges or lidocaine viscous paint will help to reduce
spray from an ultrasonic scaler. Advice on home care discomfort during eating. Paracetamol or aspirin can also
should include the purchase of a new soft toothbrush. be recommended to reduce discomfort and lower temper-
Although colonisation of the toothbrush bristles by the ature, and promethazine elixir will act as a sedative and
organisms involved in the condition is a theoretical allow sleep in the younger child.
possibility, the main reason for this advice is to ensure that When there are severe systemic symptoms, aciclovir may
an adequate brush is used. be taken either in tablet form or as an elixir. The cream
Many periodontists would prescribe the drug presentation is also useful in treating the problems of
metronidazole (Flagyl) 200 mg, taken three times a day herpes labialis.
with meals for 3 days, although for severe cases, a higher
dosage used for longer would be indicated. This
chemotherapeutic agent is very effective against the gram- MANAGEMENT OF ADULT PERIODONTITIS
negative organisms involved. However, there are some
worries about its teratogenic potential and use in preg- Adult periodontitis is, after chronic gingivitis, the commonest
nancy is contraindicated. If combined with alcohol, it may of the inflammatory periodontal diseases.The management
cause severe nausea. Penicillin is a safe and effective alter- of all forms of periodontitis is very complex and time-
native although it is less specific in its antimicrobial action. consuming, and the main principles are as follows:
It will be necessary to follow up the patient, as relapse
and recurrence are common. As the condition usually • Assessment and diagnosis of the disease. It is the respon-
occurs in patients with a pre-existing inflammatory sibility of dental surgeons to carry out screening of
periodontal condition, this will also require treatment patients under their care, to undertake an assessment
once the acute phase is under control. In some patients, and to arrive at an appropriate treatment plan.
gingival deformities caused by the interdental ulceration • Discussion of the findings with the patient. This is to
will require surgical correction, by either gingivoplasty or determine the patient’s attitudes and expectations. At
flap surgery. this stage, relief of pain, if present, may be carried out.
Decisions on any teeth of hopeless prognosis, e.g. those
with little supporting bone, should be made, to avoid
HIV-associated gingivitis
any misunderstanding about what might be achieved
This is an acute form of gingivitis seen in AIDS sufferers. with therapy. Extractions should be carried out at an
The primary treatment in these patients is directed towards early phase in the treatment plan. 33
Restorative Dentistry
• Decision on treatment strategy. Any decision on the type Box 5.3 Special investigations indicated for patients
of treatment must be made in conjunction with the with prepubertal periodontitis
patient and with fully informed consent.
• Providing advice on appropriate plaque control. This will • Whole blood count and film
• Differential white cell count
include advice on home care measures and the removal • Serum chemistry, including random serum glucose
of plaque retention factors such as calculus.This part of • Serum folate, iron, vitamin B12 and total iron binding
treatment is often called the ‘hygiene phase’ or ‘cause- capacity
related’ therapy. Home care would usually involve a sub- • Urine analysis, including glucose and protein using a
dipstick test
gingival brushing technique, interdental cleaning and,
for many patients, the use of disclosing agents where
supragingival plaque control measures are suspect.
• The use of chemical adjuncts. In some patients, the use of
chemical adjuncts to plaque control may be indicated treatment, often proves to be difficult. Some success may be
and this is discussed later in the text. obtained by the use of long courses of antibiotics, such as
• Allowing a healing period. During this phase of treatment, tetracycline, or chemotherapeutic agents such as metronida-
a period of time, often 6–12 weeks, is allowed for healing zole.The most effective therapies are thorough prophylaxis
before the tissue response is reassessed and a decision is of the active sites with a low abrasive fluoride-containing paste,
made on the need for further treatment (Box 5.2). together with flushing of pockets with an ultrasonic scaler,
making use of the cavitation and acoustic streaming effects.
For the small group of patients who do not respond to Oral hygiene should be kept simple and the child’s parent or
the above regimes, it may be necessary for periodontal guardian must be involved in its supervision and monitoring.
surgery to be undertaken.
Juvenile periodontitis
MANAGEMENT OF AGGRESSIVE PERIODONTAL
Although the treatment of these patients follows the general
DISEASES
principles laid down for adult-type periodontitis, the rapid
progression of this condition makes the monitoring much
Prepubertal periodontitis
more critical. There are two areas, however, in which
The overriding need of patients with prepubertal periodon- management does differ radically. It is now widely accepted
titis is to undertake systemic screening to identify or that these patients should be treated with tetracycline to
eliminate systemic defects. Although in many patients the eradicate the associated organisms (Box 5.4). It is a matter
results may prove negative, the identification of a serious of clinical judgement whether the antibiotic is given imme-
defect in even a small number will justify such an approach. diately the condition is diagnosed, or with mechanical root
The techniques of these investigations and their follow-up surface treatment. There is some evidence that this condi-
are outside the scope of this text, but should include, as a tion does not respond well to root debridement, and the
very minimum, the tests outlined in Box 5.3. most optimal result is obtained from a combination of early
If any of the special tests proves positive then referral to surgery and a course of systemic tetracycline.
a medical practitioner and further investigations would be
necessary, depending upon the nature of the defect. The
periodontal therapy, although secondary to the medical
Box 5.4 Recommended antibiotic regimes in juvenile
periodontitis
Box 5.2 Treatment of adult periodontitis following • Tetracycline or oxytetracycline – 250 mg four times a day
the hygiene phase for 3 weeks
• Minocycline – 100 mg twice a day for 1 week
This will depend upon the healing response and may (both pro rata depending upon body weight)
include one or more of the following:
Contraindications
• When good healing has been achieved, or if there are • Hypersensitivity to tetracyclines
signs that healing is occurring, the patient is monitored
• Pregnancy or lactating
and treatment is provided to ensure that the tissues
• Urinary tract disorders
return to maintainable health
• Recurrent candidal infections
• If a healing response is not occurring and the home care • Anticoagulant therapy
is inadequate, the cause should be sought and further
advice on oral hygiene provided Possible problems
• Where the lack of healing is accompanied by an • Care with birth control pill
adequate level of home care, root debridement would • May cause nausea, vertigo or rashes
be carried out as described elsewhere in this text • Avoid milk products, which may hinder absorption
34
5 / Management of inflammatory periodontal diseases
patient is to institute effective plaque control measures, smooth the root surface and remove a thin layer of cemen-
which should include the regular use of chlorhexidine tum, thus reducing the endotoxin burden. Some author-
gluconate mouth rinse. The mouth must be monitored on ities do not feel that effective scaling can be carried out
a regular basis and checked carefully for signs of patho- subgingivally unless followed by root debridement. Root
logical change. debridement may also be termed root cleaning or root
When HIV-associated periodontitis does occur, it planing. Both procedures need to be undertaken with
should be treated with the usual regime of scaling, root prophylactic antibiotic cover in the patient at risk of
debridement and the use of antimicrobials. If there is a infective endocarditis.
candidal infection in the mouth, this needs treatment with It is thought that root debridement reduces the amount
antifungals. of cementum-bound endotoxin to a biologically acceptable
The periodontitis should be managed conservatively level and thus allows healing of the adjacent periodontal
and surgery avoided if at all possible in view of the poor soft tissues. However, recent research has shown that
healing potential of these patients. If bone denudation endotoxin may be reduced to the level seen on healthy root
occurs, it should be covered with a dressing and antibiotics surfaces by very light root cleaning, providing that the root
prescribed in conjunction with the physician responsible surface in the pocket is instrumented in a thorough,
for the medical care. systematic way. It may well be that the only difference
between scaling, root cleaning and root debridement is the
overall reduction in root surface contaminants and these
Acute periodontal abscess
have to be lower in some patients who have decreased
A periodontal abscess occurs when pus collects in the resistance to the influence of dental plaque and its by-
connective tissue wall of a pocket and is frequently seen in products. There are, of course, differences between the
patients with periodontitis.The initial problem is managed instruments used in scaling, which is often a supragingival
by establishing drainage of this pus, so the first joint procedure, and root debridement, which is always carried
decision to be made by the operator and patient is whether out in subgingival sites.
this should be achieved by extracting the tooth. The three fundamentals which allow effective control
If it is decided to attempt to save the tooth, initial of acquired tooth surface deposits are their detection,
drainage may be obtained by scaling and root debridement adequate removal and the prevention of recurrence.
of the lesion. Should this not relieve the pressure then a Calculus deposits may be detected by visual and tactile
fluctuant lesion can be incised at its most dependent point methods. Visual detection can be aided by a stream of air
or by raising a small flap to expose the defect and allow directed at the gingival margin from the triple syringe,
effective debridement. Any local anaesthetic used should thus drying out supragingival calculus, which will lighten
not be placed into the inflamed area. and appear chalky against the tooth surface. Subgingival
The patient should be advised to use hot salt water mouth calculus may appear as a dark ring often visible through
rinses during the healing period to encourage drainage. the overlying gingiva, and deflecting the gingival margin
Once the lesion has settled, further root debridement or with the air syringe will reveal these deposits directly
surgery may be required to encourage healing.This type of (Fig. 5.2).
lesion will require careful, long-term follow-up to ensure A variety of probes may be used to feel for calculus
that recurrence does not occur. within the periodontal pocket and the two most useful are
the World Health Organization 622 probe and the cross
Scaling instruments
All hand scaling instruments consist of three basic sections:
the handle, the shank and the working tip (Fig. 5.4).
Modern scaling and root debridement instruments have
balanced grip handles, which give better distribution of Fig. 5.3 The WHO 622 probe (right) and the cross calculus probe
weight and a large area of contact for the fingers. Often the (left).
handle is hollow which, besides reducing the weight, is
claimed to give greater tactile discrimination. The shank is
that part of the instrument connecting the working tip to the Box 5.7 Guidelines to improve the efficiency of
handle. The angle and length of the shank determine the instrumentation
access obtained by the tip to the tooth surface. • Be comfortable; ensure that both you and the patient
The working tip contains the cutting edge or edges are seated comfortably
which remove the acquired deposits. Scalers are classified • Position yourself for maximum visibility. If possible, work
according to the shape of the tip, and there are five basic with the site in direct vision with a good, well-adjusted
operating light
designs: sickles, hoes, files, push (or chisel) and curettes. • Follow an orderly sequence of instrument use and make
sure they are laid out in the order of use before and
after application. This will help to avoid the time wasted
Instrumentation guidelines in searching for instruments on an untidy worktop
The successful practice of periodontics depends not only • Use as few instruments as possible and know the
function of each instrument
upon the ability to motivate patients in the daily use of • Maintain control of instruments during use, not only to
effective oral hygiene, but also on the skilful use of instru- prevent inefficient scaling but also to avoid traumatic
ments during scaling and root debridement (Box 5.7). damage caused by slipping – good finger rests are
For many patients these procedures may be undertaken essential
without any form of anaesthesia. In some cases, however, • Maintain a clear field by use of cotton wool rolls and
aspiration. Both haemorrhage and saliva will require
especially when carrying out root debridement, some control
analgesia will be required. Often the use of a topical • Ensure your instruments are sharp and serviceable
anaesthetic cream will suffice, particularly when at least • Use a slow, deliberate and methodical approach but do
2 min is allowed to elapse between application and scaling, not confuse roughness with thoroughness
so that maximum anaesthesia is achieved. When topical • Always talk to the patient in a friendly and sympathetic
manner not only on completion of the task but also
anaesthesia is inadequate, block or infiltration anaesthesia during the procedure. This ensures that the patient
will be required; some patients will need even this to be adjusts to the procedure even if he or she found it
reinforced with inhalation relative analgesia. difficult and time-consuming
The instrument should be held in the correct way, as • Always clean up the patient before departure from the
this will determine the amount of control and thus the surgery. This is a courtesy appreciated by all patients
• Use effective techniques as described in the text
stability and effectiveness in use. There are three possible
ways to hold a scaler:
horizontal patient does require three important precautions supragingival calculus. Hoes such as those in the MacFarlane
to be taken: set (Fig. 5.10) are suitable for scaling mesially, distally,
facially and lingually, whilst modified hoes (Fig. 5.11) are
• Eyesight protections must be provided. useful for scaling and root debridement in furcations.
• The airway must be watched carefully and protection
in the form of a butterfly sponge used if necessary. Method of use. The working tip is slid down the root
• Some method of moisture control will usually be required. surface over the calculus until the bottom edge is palpated.
Pressure is applied to hold the hoe against the deposits
Hand instruments and the shank against the crown. The instrument is then
moved towards the crown to plane away the calculus.
The sickle scaler
This is a generic term which includes all scalers with a The periodontal file
working tip projecting from the shank at approximately a
right angle and having a sharp pointed end (Fig. 5.9). The This file has a series of cutting edges set at right angles to
method of use may be by pulling, such as the Jaquette the shank on a round, oval or rectangular base (Fig. 5.12).
no. 1, or rotation of the handle (Jaquette nos 2 and 3 and Uses. The file is used for subgingival scaling and root
hygienist sickles). They have two cutting edges which are debridement, but will not cope with heavy deposits which
formed by the convergence of the top surface and the two must be removed with a hoe scaler first.
lateral surfaces. The cross-section of the working tip is
triangular in shape. Method of use. The instrument is slid down the root
surface to the lower edge of the calculus. Pressure is
Uses. The sickle scaler is used mainly for supragingival scaling.
applied to hold the cutting edges and the shank against the
It may also be used to scale or root plane just beneath to
the gingival margin, provided the gingival pocket is fairly
loose. This instrument should not be inserted too deeply
into a pocket as the sharp tip will lacerate the soft tissue wall.
Method of use. The cutting edge is placed against the
tooth if possible with a positive rake angle, but 90° is an
acceptable compromise. It is then moved up the tooth with
a pull stroke.
Fig. 5.9 The sickle scaler used to remove subgingival calculus in Fig. 5.11 A modified curette useful for scaling the roof of
an accessible area. furcations. 39
Restorative Dentistry
tooth, and the instrument is moved towards the crown, Uses. The curette is the principal instrument for fine
removing the deposits. The design of a file requires subgingival scaling, root debridement and root surface
repeated strokes to be made whilst instrumenting an area. smoothing. It may also be used for curetting the soft tissue
wall of the pocket, a procedure called subgingival
curettage, which is no longer favoured in western Europe.
The push scaler
The push, or chisel, scaler has a single straight bevelled Method of use. The working tip is inserted into the base
cutting edge set at right angles to the shank (Fig. 5.13). of the pocket and tilted to give a positive rake angle. It is
used with a pull stroke towards the occlusal surface.
Uses. The push scaler is used to remove heavy deposits of
supragingival calculus from the interdental surfaces of the
anterior teeth. It should only be used when the embrasure Powered scalers
spaces are open and sufficient space is present.
Powered scalers are used in dentistry to remove plaque,
Method of use. The cutting edge is placed from the labial calculus and stains from the teeth. The use of these
aspect against the tooth surface and pressure is applied to automated scaling instruments makes the work of the
cleave away adhering calculus deposits. operator much easier, and for many patients makes the
scaling procedure more acceptable. They have a valuable
role in the removal of gross deposits and flushing out
The dental curette
the pocket. Ultrasonic scalers operate between 20 and
This has a spoon-shaped working tip with a curved cutting 40 kilohertz (kHz) and sonic scalers in the 3–6 kHz range.
edge. There are two principal types: the universal with two Both types of instrument need a water spray, as heat is
cutting edges, and the site-specific which has a cutting produced during use at the working tip and the cooling
edge on one side only (Fig. 5.14). spray has the additional advantage of washing away dis-
(a) (b)
40 Fig. 5.14 (a) Universal dental curettes (Langer’s). (b) Site-specific dental curettes (Gracey’s).
5 / Management of inflammatory periodontal diseases
lodged deposits, but also the distinct disadvantage of the root surface. A variety of differently shaped tips is
producing an aerosol. Box 5.9 provides a comparison available to achieve this result. There are differences in the
between ultrasonic and sonic scalers. oscillatory patterns of ultrasonic and sonic scalers. The
ultrasonic has a higher energy output and is not easily
Ultrasonic scaling instruments. These operate at
damped by loading and is generally a linear action. The
frequencies above the level of human hearing, usually
sonic scaler has a larger, usually circular and more coarse
between 20 and 40 kHz.There are two different types avail-
pattern of movement to compensate for the lower energy
able on the market: magnetostrictive and piezoelectronic.
level and is more easily damped by high loading, although
Magnetostrictive types. These use a core or stack of this may not be obvious to the operator. It is, however,
magnetic material, usually a nickle alloy, which is acted easier to sterilise than the ultrasonic instrument.
upon by electrical windings in the handpiece producing an
Cavitational effects. These are usually seen with the
alternating magnetic flux. When the stack is magnetised,
ultrasonic scalers as the sonic variety do not generally have
it contracts and as it is connected to the working tip this
sufficient energy output at the tip to cause cavitation. All
mechanical change is relayed to the tooth surface. The
powered scalers are provided with a flow of cooling water
electronics of the unit changes the alternation of the
directed at the tip to remove any heat caused by friction
magnetising current to an ultrasonic frequency, causing
between the tip and the tooth surface. The water contains
the tip to vibrate at a similar rate.
minute air bubbles which are expanded by the energy in
Piezoelectronic types. A piezoelectric material such as quartz the vibrating tip which causes them to have a negative
will oscillate if an ultrasonic current is placed across it.This internal pressure for a fraction of a second and then
vibration is then transferred to the attached scaling tip. implode, releasing large shock waves. Such forces have
been shown to remove plaque and calculus from the tooth
Air or sonic scalers. Sonic scalers are operated by a surface. One of the side-effects of the water flow and
pressurised air line usually connected to an air turbine. cavitation is the generation of a large aerosol against which
This air is passed over a reed or through an eccentric cam precautions should be taken.
in the handpiece which then vibrates in the air flow. Sonic
scalers operate at frequencies below that of the limit of Acoustic microstreaming. All powered scalers set up
hearing, typically in the 3–6 kHz range. vigorous movements of the water around their tips and
this is termed acoustic microstreaming. The large shear
forces associated with this phenomenon assist in the
Method of action removal of some of the tooth surface deposits and in the
The removal of calculus and other deposits by mechanical disruption of plaque colonies.
scaling instruments is achieved in three ways: mechanical Both the cavitational and acoustic microstreaming
abrading action, cavitational effects and acoustic micro- effects produce an intense acoustic turbulence around
streaming. the scaling tip. This has been shown to assist the root
debridement process by scrubbing the root surface and
Mechanical abrading action. The action is a mixture of disrupting associated bacteria.
back-and-forth and circulatory movements and this
mechanically abrades and chips away at the deposits on
Principles of use of powered scalers
Modern ultrasonic scalers are self-tuning and have a
Box 5.9 A comparison between ultrasonic and sonic variable power control. The higher the power setting, the
scalers greater the vibration and the more likely it is for the
Ultrasonic patient to experience discomfort. In general, a low to
• Electrically powered, tip vibration above 20 kHz medium setting should be used and this has the added
• Oscillatory pattern variable but often linear advantage of reducing the risk of unwanted tooth surface
• Cavitation occurs in water stream close to the tip
• Acoustic microstreaming occurs damage. Studies have shown this to be just as effective for
• Not easily damped by loading periodontal healing. The instrument should be positioned
• Not all models are easy to sterilise with the oscillating working tip almost in the long axis of
Sonic the tooth with a very small rake angle. Light pressure
• Air-powered, tip vibration between 3 and 6 kHz should be applied and the tip kept constantly on the move
• Oscillatory pattern usually circular or elliptical with a light circulatory stroking action. The tip should
• Cavitation not present not be held stationary in any one area for too long as this
• Acoustic microstreaming occurs will cause excessive abrasion of the tooth in that area.
• May be damped by excess loading
• All models are sterilisable Instrumentation should not be rushed and the surface
should be checked from time to time for smoothness. This
can be done with the tip without the power on. 41
Restorative Dentistry
laden cementum as well as all deposits of plaque and ANTIMICROBIAL ADJUNCTS IN PERIODONTAL
calculus. The root surface should be left clinically smooth. THERAPY
This will encourage resolution of inflammation and
healing of the site. When inflammatory periodontal diseases are present,
If these aims are achieved then the root surface should effective removal of plaque deposits on a regular basis will
be rendered biologically inert and the persistent periodontal usually return the inflamed tissues to health. Mechanical
lesion begin to resolve. For the majority of patients, local oral hygiene measures are sufficient to reverse early gingivitis
anaesthesia will be required for the teeth to be root- provided that tissue swelling has not reached a level where
planed. In the maxilla this will require the use of infiltra- subgingival plaque is protected from the cleaning aids, or
tion techniques, but in the mandible, block anaesthesia calcified deposits hinder effective plaque removal. In these
together with a long buccal infiltration is necessary. cases, additional scaling and polishing are also required.
Instrumentation during root debridement is very However, it has been shown that oral hygiene does not
similar to that used during subgingival scaling, but the eliminate inflammation in periodontitis where pocketing is
technique is more exacting, although often there is no present. Subgingival scaling, root debridement, local and
calculus to remove. It is again worthwhile to commence systemic antimicrobials and surgery may all be required
and finish with an ultrasonic scaler as there is some to render the root surface free from microbial deposits
evidence of improved healing following its use. To permit and permit healing. Current mechanical therapy aims at
the ultrasonic tip to reach the base of the pocket, the use providing regular pocket debridement to eliminate most
of modern slimline scaling tips is essential. subgingival plaque and calculus, and so prevent the
The method of use of instruments also varies from development of microbial complexes which may result in
scaling. The initial strokes should be made from the base disease progression. A sustained reduction in the levels of
of the pocket up the root surface with an overlapping pathogenic microorganisms occurs in periodontal pockets
technique as shown in Figure 5.15. This should be following this therapy. The results of clinical studies also
followed by a consolidating series of movements at 45° support the value of regular maintenance care, and an
to the initial strokes. In this way the root surface is quar- appropriate interval for remotivation and plaque removal
tered by the instrument and the majority of the contam- appears to be 3-monthly. However, oral hygiene practices
inated cementum removed. The pocket is then flushed may not be successful for the reasons given in Box 5.10.
with the water spray to remove loosened deposits. This As a result chemical antimicrobials are often used as
may be achieved by using the ultrasonic scaler, provided adjuncts in the management of inflammatory periodontal
care is taken not to further roughen the root surface diseases.
following the hand smoothing. Finally the pocket is
irrigated with an anti-plaque agent such as 0.2%
Mouth rinses
chlorhexidine digluconate.
Contraindications to root debridement are poor patient Various chemicals have been used in the form of mouth
motivation, teeth of a hopeless prognosis, severe dentinal rinses to assist in the treatment of inflammatory
sensitivity (which will be worsened by the procedure) and periodontal diseases. The influence of mouth rinses on
the presence of acute infection. the course of inflammatory periodontal diseases may be
categorised as follows:
• They may alter the plaque environment by changing, Box 5.11 Characteristics of mouth rinses
for example, the acidity.
• Vary in their activity against microbial plaque
As a general rule, mouth rinses will act at either the plaque • Have differing retention times in the oral cavity
level or, to a very limited extent, at the tissue response level (substantivity)
(Fig. 5.16). Despite these limitations, there are situations • Useful in the treatment of gingivitis
• Limited effect on periodontitis as they do not penetrate
when the use of a mouth rinse is clearly indicated: pockets to any significant extent
• Potential side-effects such as severe extrinsic tooth
• when gingivitis does not respond to oral hygiene staining limit their usefulness
measures and good home care • Most effective when used following careful scaling and
• for patients with oral ulceration such as aphthae or root debridement
herpetic lesions • Retard the subsequent recolonisation of pockets
following periodontal therapy and lead to a greater
• for patients suffering from oral mucosal conditions such
reduction of inflammation when used following root
as lichen planus and benign mucous membrane debridement
pemphigoid
• when jaws are fixed together such as following fractures
or jaw surgery
• following periodontal surgery, to permit adequate
healing when plaque control may be painful Amongst commercial dental companies there has
• for very high-risk patients such as those who are been considerable interest in mouth rinses containing
immunocompromised, e.g. following renal, liver or cetylpyridinium chloride (CPC). CPC in the laboratory has
heart transplants. considerable bactericidal activity. However, the retention
time or substantivity of CPC in the oral cavity is limited
The general characteristics of mouth rinses are outlined and therefore frequent use is required to provide any
in Box 5.11. useful anti-plaque activity. These mouth rinses have a less
unpleasant taste and fewer staining problems than
experienced with chlorhexidine.
Chemicals in mouth rinses
Another mouth rinse is 1% w/v povidone-iodine, a formu-
The most effective anti-plaque mouth rinse at the present lation which is claimed to overcome the very occasional
time is the bis-biguanide salt chlorhexidine gluconate, which mucosal sensitivity reactions that occur with the use of
has a broad antimicrobial spectrum and is active against chlorhexidine. It should be noted that the prescribing
both gram-positive and gram-negative bacteria. Another information supplied by the manufacturer for this mouth
mouth rinse, in addition to chlorhexidine, which has been rinse includes the possibility of mucosal irritation and hyper-
approved by the Council of Dental Therapeutics of the sensitivity reactions, and its use is contraindicated in preg-
American Dental Association, is a phenolic anti-plaque compound nant females and young children. Prolonged use is not recom-
with anti-inflammatory properties (Listerine). Research has mended and it should not be used for more than 14 days.
shown that, although this formulation has less anti-plaque Another chemical, triclosan, has proved to be very useful
and antimicrobial activity than chlorhexidine, when used in toothpastes.When used as a mouth rinse combined with
as a supplement to normal oral hygiene it has a similar zinc salts or co-polymer, it has moderate substantivity and
effect in reducing the clinical gingivitis scores. In addition, gives beneficial plaque reductions.
phenolic anti-plaque compounds have been shown to have Chlorine dioxide-containing mouth rinses have been
anti-inflammatory effects at subclinical concentrations. claimed to eliminate volatile sulphur compounds and thus
reduce halitosis.
Subgingival antimicrobials
concentrations is used in many mouth rinses. Its main
functions are to act both as a preservative and as a solvent, Local drug delivery has been advocated in the management
to stabilise and solubilise various flavouring and active of periodontitis, as an addition to mechanical subgingival
ingredients in the mouth rinse. The pH of the rinse is debridement, in order to overcome the problem of deliver-
usually a product of the total acid content countered by ing antimicrobials into periodontal pockets. In the UK,
the buffering capacity of the other constituents. Recently, the following commercial subgingival antimicrobial systems
the adverse effects of acidic drinks on dental enamel have are currently available:
been documented and it is possible that acidic mouth
rinses may have a similar effect. • 2% minocycline gel (Dentomycin) – requires three or
Of concern is the fact that the concentration of alcohol four applications every 2 weeks with no repetition
in some mouth rinses equals or exceeds that in many within 6 months. It inhibits most periodontal pathogens
alcoholic beverages and if used over a long term could be but is rapidly cleared from pocket
a contributory factor in oral cancer, but there is some • 25% metronidazole gel (Elyzol) – applied twice at
disagreement over this. There is also the possibility that 1-week intervals; this product has a slow-release base
acute ethanol toxicity could occur following ingestion of (biodegradable monoglyceride gel rich in mono-olein
large quantities of mouth rinse. The greater danger lies with sesame oil)
with ingestion by children, where only a small volume is • 25% tetracycline hydrochloride in ethylene vinyl acetate
needed to produce morbidity and mortality. co-polymer monofilament (Actisite) – this elastic cord
In response to their possible drawbacks, many manu- is packed into the pocket and left for a 12-day period.
facturers are taking steps to remove alcohol from their Despite being very time-consuming to insert, Actisite
products and to ensure that any acidity is well buffered or has long retention and sustained release. There is, how-
that the pH is neutral. ever, a subsequent need to remove the cord which is
very bulky in the pocket
• 55% chlorhexidine gluconate in hydrolysed gelatine
Summary
(Periochip) – this is based on a sustained-release device,
It may be concluded that mouth rinses are beneficial for which is a method of delivering the antimicrobial
patients with gingivitis not responding to local mechanical subgingivally over a prolonged period of time. It is very
treatment or with specific problems which prevent normal easy and quick to insert with minimum discomfort to
oral hygiene. For patients with periodontitis, their use is the patient. The product is biodegradable so there is
more limited, although the most effective time for using a no need to remove it, and it has been shown to have
mouth rinse is immediately following non-surgical or effective activity over a 10-day period.
surgical periodontal therapy. However, as with any agent
used in medical treatment, the dental practitioner should
Subgingival irrigation
be aware of the potential disadvantages of the product, as
well as the possible therapeutic gain (Box 5.12). Another method of local drug delivery is by the use of
pulsed oral irrigation systems, which are supplied with
modified tips to allow professional subgingival irrigation in
Box 5.12 Potential disadvantages and therapeutic
the surgery.
gains resulting from the use of mouth rinses At home, local antimicrobial delivery may be achieved
by irrigation using a blunt syringe or a pulsed oral
Disadvantages
• Superficial reduction in inflammation, leading to loss of irrigator. However, the syringing of periodontal pockets
warning signs can be a time-consuming procedure and many patients
• Reduction in efforts at mechanical plaque control will not possess a sufficient degree of manual dexterity
• Concern over alcohol content of some products to undertake effective local drug delivery. Many of the
• Concern over acidity pockets may be in posterior areas and are not very
• Problems of long-term use of chemicals
• Sensitivity to mouth rinse constituents in small numbers accessible. Concern has also been expressed about the
of subjects high pressures that can be exerted using subgingival
irrigation with syringes and blunt needles. However, it
Therapeutic gains
• Improved reduction in plaque levels has been shown that, unlike syringe irrigation, most pulsed
• Increased reduction of gingivitis oral irrigators produce low pressures which are tolerated
• Pleasant taste by the tissues. In addition, the use of pulsed irrigation
• Plaque reduction in inaccessible areas or when may allow lower concentrations of chemicals to be used.
conditions do not permit oral hygiene (e.g. with However, the amount of the antibacterial agent delivered
ulcerative conditions)
• Anti-caries effect of fluoride content to the site is the critical factor in achieving its maximum
effect. For these reasons, the use of a pulsed oral irrigator
has been suggested as a practical alternative to syringing. 45
Restorative Dentistry
Pulsed oral irrigation. Irrigation is achieved by the action pulsed irrigation is only useful as an adjunct to standard
of a small motor which activates a pump. Water is fed to therapy in selected patients.
the pump from a reservoir and is emitted via a handpiece In contrast, when there are problematic lesions, e.g.
into which a variety of tips can be fitted. These permit deep pockets, furcations, complex fixed oral appliances or
both supra- and subgingival irrigation to be undertaken. refractory periodontitis not responding to standard therapy,
There are minor differences between the various makes, pulsed irrigation with a suitable chemical may enable these
some having pressure-limiting systems to prevent excess patients to improve their periodontal healing further. It is
pressure being applied whilst maintaining the pulse rate. unrealistic to expect all patients with periodontitis whose
Some machines are supplied with a range of supra- and pockets exceed 3 mm – and which therefore are not acces-
subgingival applicators for home and surgery use. sible to the toothbrush or interdental aids – to constantly
prevent colonisation with disease-associated periodonto-
Clinical effects. Studies have shown that pulsed oral pathic organisms. Where the will and ability exist to carry
irrigation after scaling and root debridement may further out meticulous mechanical oral hygiene measures, these
reduce plaque levels, bleeding index and pocket depths, are at best crude and inefficient means of removing
especially when combined with an antimicrobial. With organisms from the periodontal tissues. It must therefore
regard to the most efficacious chemical for use with such be concluded that pulsed oral irrigation has potential in
a system, chlorhexidine appears to be the agent of choice, the management of inflammatory periodontal diseases.
although there is no agreement as to the most appropriate
concentration. Indeed, there is considerable disagreement Safety. High irrigation pressures may propel organisms
as to the activity of chlorhexidine in periodontal pockets. into the gingival tissues and both abscesses and
Experience in our clinics suggests that a 0.05% concen- bacteraemias have been reported. However, studies have
tration in an oral irrigator is sufficient to improve most shown that, provided the irrigation pressure does not
patients with significant periodontitis, although many exceed 480 kPA, no soft tissue injuries occur. It has been
other chemicals have also been shown to improve clinical shown that a pulsed oral irrigator exerts a pressure that is
parameters. tolerated by the tissues.
There is general agreement in the literature that pulsed When using an apparatus that combines water with an
oral irrigation reduces gingivitis and improves the efficiency electrical supply, the issue of electrical safety must also be
of antimicrobial chemicals. However, when the efficacy of addressed and it is preferable that a safety outlet, such as
scaling and root debridement is compared with subgingival a razor socket, be used. On no account should a trailing
irrigation, the former is the most effective. Therefore, cable be taken into the bathroom.
46
6 Occlusion
attached to the medial and lateral heads of the condyle and Orbiting condyle Rotating condyle
as such the disc sits on the condyle like a cap.
pation of the teeth occurs. By virtue of the anatomical the rest position their horizontal axis of rotation is termed
fixed relationship of the condyles to the mandibular teeth the terminal hinge axis. In the absence of TMJ pathology
the rest position of the condyles in intercuspal position is and masticatory muscle dysfunction, the RP and associated
directly related to the nature and quality of the teeth. terminal hinge axis are reproducible fixed anatomical
Intercuspal position is determined entirely by the position landmarks from which accurate geometric measurements
and morphology of the teeth; however, interventive dental may be established. During the initial pure rotational
care can, and readily does, alter the position and border movement the condyles remain in the RP with the
morphology of the teeth and as such can change or consequence that this position can occur over a limited
influence the resting position of the condyles. range of mandibular opening, the resultant arc of move-
In the absence of any dental influence the resting ment being termed the retruded arc of closure. The
position of the condyles is determined by the anatomical mandibular position at the occlusal end point of the
and physiological nature of the TM joints and masticatory retruded arc of closure is termed the retruded contact
musculature. Under these criteria the head of the condyle position (RCP). Retruded contact position is alternatively
appears to be accommodated in a superior position within termed centric relation contact position (CRCP).
the glenoid fossa; as a result there has existed historically The great majority of individuals do not exhibit perfect
a common misconception that at rest the condyle coincidence between RP and ICP. The relationship of the
articulates superiorly. It would be reasonable to reach this RCP to ICP is influenced by the deflective contact. The
conclusion if one’s observations were based on assessment deflective contact may be defined as an occlusal inter-
of tomographic radiographs of the TMJ, experience of ference the presence of which prohibits RCP–ICP coin-
dry specimens and the perceived wisdom of the time. cidence. The teeth must therefore slide down or over
Observations such as assessment of cadaver specimens, the deflective contact to establish ICP. Posselt reported
MRI images of functioning joints in healthy individuals that 90% of individuals have an RCP to ICP movement
and histological observation of the joint components of 1.25 ± 1 mm. Some authorities alternatively term the
provide a more rational assessment of the condylar articu- deflective contact the premature contact.The term premature
lation. The condylar head at rest is accommodated in a contact should not be used in relation to the natural den-
superior position within the glenoid fossa; however, the tition and is more appropriate to the artificial dentition.
condyle articulates with the posterior aspect of the With complete dentures, there is no natural intercuspal
articular eminence. position, and ICP and RCP are made to coincide. The
When this relationship occurs the mandible is said to be patient learns, subconsciously, to close into maximal inter-
in the retruded position (RP). This position can therefore be cuspation. When, as a result of inaccurate occlusal regis-
defined as that relation of the mandible to the cranium tration, the ICP and RCP of the complete dentures do not
that occurs when the condyles are on the articular discs coincide, the patient may slide into maximal intercuspa-
and located at their mid-most, most superior position on tion or alternatively the dentures may move.This is known
the posterior aspect of the articular eminentiae. The RP as premature contact and is clearly unsatisfactory. The
position is alternatively termed centric relation position (CR) artificial teeth do not have a periodontal proprioceptive
and the condyles are said to be in centric relation. system, and so the position of an artificial ICP cannot
Some authorities consider the use of the expression readily be detected. With a natural dentition the ICP is
‘centric’ potentially misleading, favouring the use of the well recognised by the neuromuscular mechanism and the
term ‘retruded’. They consider that centric relation and mandible closes habitually into ICP in the majority of
centric occlusion may be easily confused as a result of their involuntary closing movements. It may not be so in the
similarity. They also consider that ‘centric’ implies dental chair when the mandible is brought under volun-
centricity of the condyles in their fossae, centricity of the tary rather than involuntary control. In these circum-
midline of the mandible with the midline of the face, or stances, even if the first contact appears to be a premature
centricity of the cusps within the fossae of the opposing contact, this should not be assumed to be the normal
teeth, none of which may be the case. Whilst accepting the pattern of closure, but only the result of the patient concen-
rationality of this premise, it can be argued that the use of trating on a movement that is usually entirely automatic.
the expression ‘retruded’ may give rise to at least a similar For these reasons the term premature contact should be
potential for misunderstanding and inappropriate tech- avoided in relation to the dentate patient.
nique. It cannot be emphasised enough that the RP is not
the most retruded, distal or posterior position the mandible
can obtain. The condyles can by means of inappropriate OCCLUSAL INTERFERENCES AND OCCLUSAL
manipulation, especially in a less than healthy individual, HARMONY
be forced posteriorly.
The RP should be an unstrained and comfortable The deflective contact has been presented as an example
position in which the condyles are allowed to adopt their of an occlusal interference. An occlusal interference may
superior-anterior articulation. When the condyles are in be defined as any occlusal contact that gives rise to 51
Restorative Dentistry
(a) (b)
Fig. 6.8 (a) Full coverage occlusal appliance constructed for maxillary arch. (b) A clinical view of appliance in place providing right lateral
guidance.
Fig. 6.10 The average movement articulator. Fig. 6.12 The face bow is used to relate the condylar axis to the
occlusal plane and provides further accuracy in replicating the
movements of the patient’s mandible.
The average movement articulator (Fig. 6.10) introduces The face bow is used to relate the terminal hinge axis to
some lateral movement to the assembly. The condylar the occlusal plane and provides further accuracy in
guidance angle is set at 30° to the horizontal. This is taken replicating the movements of the patient’s mandible (Fig.
from an average value of the general population and 6.12). Articulators may be classed as being either arcon or
attempts to reproduce the movement of the mandible non-arcon. Arcon stands for articulator condyle and the
moving downwards in the glenoid fossa.There is an incisal term relates to whether the condyles are fixed to the lower
pin which is set to contact a guidance table. The table has arm such as with the Whipmix (arcon) or to the upper arm
an average guidance of 10° which once again is a repre- (non-arcon).
sentative value taken from the general population. Finally there are fully adjustable articulators available
An adjustable articulator such as the Whipmix articu- which may be made to closely reflect the individual patient’s
lator (Fig. 6.11) allows for the side shifting of the artificial jaw movements and are beyond the scope of this text. The
condyles to take place. There is also the ability to adjust use of articulators covers a broad spectrum of movements
the guidance angles of both the condyles and the incisal from the simple hinge which only allows for an opening
table to take account of individual movements. Articulators movement in the vertical plane to the fully adjustable articu-
allow a face bow transfer to be attached at the time of lator which attempts to fully reproduce all the possible move-
positioning the upper cast. ments of the natural temporomandibular joint. The use of
the articulator will be discussed further in Chapter 12.
SUMMARY
56
7 Caries and other reasons
for restoring teeth
(a)
(b)
Fig. 7.1 The restorative cycle. (Adapted from Dietschi & Spreafico 1997, with permission of Quintessence Publishing.)
Fig. 7.2 The caries balance. (Adapted from Featherstone J D (1998). Prevention and reversal of dental caries: role of low level fluoride.
58 Community Dentistry and Oral Epidemiology;27(1):31–40. Munksgaard International Publishing. With kind permission of Blackwell Publishing.)
7 / Caries and other reasons for restoring teeth
7.5
Diabetic
chocolate Box 7.2 Caries terminology
7.0 Anatomical
• Enamel caries
• Root caries
• Occlusal caries
6.5 • Smooth surface caries
Chocolate • Interproximal caries
Condition of site
6.0
• Primary caries
• Secondary caries/recurrent caries
• Residual caries
0 3 7 11 15 19 23 27 Activity
Minutes • Active lesion
Fig. 7.3 Typical pH curve following ingestion of two types of • Arrested or inactive lesion
chocolate. • Remineralised lesion
• Chronic lesion
Others
Box 7.1 Medications which may reduce salivary flow • Rampant caries
– Bottle (nursing caries)
• Antidepressants, tranquillisers and hypnotics – Early childhood caries
• Antihistamines and anti-nausea drugs – Radiation caries
• Anticholinergics and muscle relaxants – Drug-induced caries
• Antihypertensives and diuretics • Hidden caries
• Appetite suppressants • Incipient lesions
59
Restorative Dentistry
hydroxyapatite, in the presence of fluoride, permits the amenable to remineralisation and long-standing dentine
incorporation of further calcium and phosphate to create lesions that are hard, black and shiny are not uncommon.
a surface coating of fluorapatite which has a reduced In an ageing population that are retaining their teeth for
solubility (critical pH) and hence it confers some caries longer, root caries is likely to be a major challenge in terms
protection to the lesion surface (Figure 7.4). of detection, diagnosis and management.
The extent of the subsurface lesion may progress and The stage of the lesion is one variable in the clinical
involve the underlying dentine, become radiographically decision-making process to treat a tooth; either by preven-
visible and yet still retain a visually intact surface. Such tative or surgical means. However, the caries diagnostic
lesions may still be amenable to remineralising therapy; process is a complex one involving a variety of assessments
and, depending on both tooth and patient factors, a deci- that should be carefully weighed by the clinician before a
sion to monitor may be justified. If demineralisation con- treatment strategy is developed.
tinues, the undermining of the surface will eventually lead
to cavitation, creating a protected environment in which
Caries detection and diagnosis
acidogenic bacteria can thrive.The further complication of
a difficult to clean site renders further remineralisation An important distinction should be made between caries
a remote possibility. Further spread into dentine results in detection and diagnosis. Detection is the process of identi-
bacterial colonisation of the hard tissue with resulting fying an area of demineralisation, and this can be under-
dentine softening and continued undermining of enamel. taken either visually, or by one of several novel devices.
In rare cases, extensively cavitated lesions may reminer- However, the process of diagnosis is undertaken by a
alise, their bases becoming black and hardened as a result trained clinician, who collates information from a variety
of improved access and cleaning. However, rapidly pro- of sources before deciding upon a diagnosis and appro-
gressing caries quickly overtakes the protective mechanisms priate treatment plan. In caries diagnosis, there should be
of the pulp and vitality is hence threatened. the identification of a lesion (presence of demineralisation),
Caries of root surfaces is essentially the same physio- the severity of the lesion (depth) and whether or not it is
logical process although the differences in presentation and progressing (active) or if it is arrested; therefore intrinsic
natural history are important. The differing biochemical within caries diagnosis is an assessment of activity. Such
and optical properties of dentine preclude the development an inclusion is essential as it will inform, to a great degree,
of a white spot and hence the initial mineral loss may be the treatment plan that will follow the diagnosis. For
difficult to detect clinically. Unlike enamel when lesions example, it would be inappropriate to restore an arrested
are well hydrated there is often little loss of profile or lesion that was of no aesthetic concern to the patient.
structure. The softened dentine is particularly susceptible To identify a caries lesion, the tooth surface must be
to further physical or chemical damage, but is also clean and dry. In fact the individual drying of teeth with
Critical pH Critical pH
of HA of FA
pH 6.8 6.0 5.5 5.0 4.5 4.0 3.5 3.0
Demineralisation
Dissolution of HA
Production of HA and FA FA forms if fluoride available Acid
calcium and phosphate dissolution of
in saliva Remineralisation crystal
FA reforms
HA is hydroxyapatite FA is fluorapatite
Fig. 7.4 Demineralisation and remineralisation cycle for enamel caries. (Adapted from. Mount G J & Hume W R (1998) Preservation and
60 Restoration of Tooth Structure with permission of Mosby.)
7 / Caries and other reasons for restoring teeth
compressed air is an essential step in the classification of There are a number of techniques that can augment
lesions; and may be an indicator of their potential to visual examinations, for example fibreoptic transillumi-
remineralise. On smooth surfaces, the classic ‘white spot’ nation (FOTI). In this technique a high intensity light is
is seen although long-standing lesions may become darker shone down a narrow aperture probe on to the surface of
as they take up extrinsic stain (Fig. 7.5).The use of a sharp the tooth. Due to backscattering caused by demineralised
probe is not recommended as this can damage early enamel, carious lesions restricted to enamel appear dark,
lesions causing cavitation and make remineralisation more with those extending into dentine appearing orange
problematic. Some dentists believe that moving a probe (Fig. 7.7). FOTI provides an increased sensitivity to visual
from lesion to lesion will facilitate the spread of microor- examinations and enables clinicians to discriminate more
ganisms. Bite wing radiographs are an essential aid in the easily between those lesions restricted to enamel and those
diagnosis of approximal caries, although the radiographs extending into dentine. An advanced version of the system
will underestimate the extent of the histological lesion by incorporates a small camera enabling the images to be
as much as a third. Bite wing radiographs are of little use viewed on a computer screen and retained for longitudinal
in the detection of early occlusal caries (when it can be monitoring; this system is known as digital image FOTI,
seen, it is invariably well into dentine), which remains a or DiFOTI (Fig. 7.8). A further technique of use in a visual
difficult diagnostic challenge, even for the most experienced examination is the use of orthodontic elastics to separate
clinicians. Bite wings should always be taken using a film adjacent teeth allowing, after 5–7 days of placement, to
holder to ensure that the beam is at right angles to the film visualise directly the proximal surface of the tooth.
and the contact areas of the teeth. (Fig. 7.6). Other techniques for caries diagnosis include laser
fluorescence (DiagnoDent, KaVo), light fluorescence
(QLF, Inspektor), electronic caries monitor (ECM, Lode)
as well as some more developmental systems such as ultra-
sound or thermal imaging. The DiagnoDent device (Fig.
7.9) is a small, compact unit that uses the fluorescence of
bacteria, or their metabolic products, to detect if a lesion
is present. Two tips are supplied with the system, one for
smooth surfaces and the other for fissures, and this is
simply placed on the area of interest. Within a second a
digital readout presents a number from 0 to 99. A number
of researchers have suggested interpretative indices so that
clinicians can relate these values to a clinically relevant
description, i.e. >30, caries into dentine. The system is
simple to use but research suggests that it is adversely
affected by stain, and the angulation of the tip is critical to
obtaining meaningful results. The QLF system uses an
intraoral camera to capture fluorescent images of tooth
Fig. 7.5 Example of early white-spot lesions on the labial surfaces
of maxillary incisors. Such lesions are amenable to surfaces.The system enhances the contrast between sound
remineralisation.
Fig. 7.6 Example of a bite wing radiograph. Note caries between Fig. 7.7 Example of fibreoptic transillumination highlighting
the mandibular first molar and second premolar. dentine caries in a premolar. 61
Restorative Dentistry
(a) (b)
(c) (d)
Fig. 7.8 Example of digital fibreoptic transillumination (courtesy of Professor George Stookey and Dr M Ando, University of Indiano).
(a) Imaging of occlusal and interproximal surfaces. (b) Imaging of smooth surfaces. (c) Demonstrating image of occlusal and interproximal
lesions. (d) Example of a smooth surface lesion.
and demineralised enamel by at least ten times, and hence for example ‘hidden caries’ where visually intact occlusal
it is easier to visualise early caries (Fig. 7.10). Software surfaces are revealed, following radiography, to have exten-
accompanying the system permits dentists to quantify the sive dentine lesions. However, careful clinical examination
degree of mineral loss and then monitor the lesion over of clean, dry teeth, combined with careful, selective and
time to determine if a given tooth is responding to preven- properly indicated radiographic views, should enable the
tative care, or if restorative intervention is required. clinician to gauge the likely severity of most lesions.
The electronic caries monitor measures the resistance The final stage in the diagnostic sequence is estab-
of the tooth to a mild electrical stimulus and is related to lishing whether or not the lesion is active. It can be argued
the porosity of the lesion (Fig. 7.11). Used in combination that the only way that this can be truly established is by
with a 5-second compressed air jet, the system relates the monitoring the lesion over time and detecting changes.
time taken to stabilise, with larger, wetter lesions taking Before the advent of the QLF and DiagnoDent systems
longer to stabilise then smaller, dryer ones. The ECM tip this was impossible in all practical clinical situations, as
is very small, and suffers from issues of reliability when one simply cannot recall accurately the status of the lesion
successive measurements, so important in measuring caries from one visit to the next. However, both of these systems
activity, are taken over time. All of these systems should enable early lesions to be followed and their activity deter-
be considered as additional tools in the armamentarium mined. It is interesting to note that the QLF system can
of the clinician and enhance, but do not replace, effective detect the products of bacterial metabolism, and these are
diagnosis by a clinician. shown in red on fluorescent images. It has been proposed
Once the presence of demineralisation has been estab- that lesions that exhibit this red fluorescence are at an
lished, the next stage of the process is to determine the increased risk of progression as they contain metabolically
likely severity of the lesion, most often interpreted as the active bacteria. Should clinical trial evidence support this,
depth of the lesion. Caries progresses in a generally pre- it could be one method by which activity could be measured
62 dictable way, but the visual indications can be confusing, in a single visit (Fig. 7.12).
7 / Caries and other reasons for restoring teeth
Fig. 7.9 The DiagnoDent device (a) The system box, indicating
Table 7.1 Risk factors for the development of caries.
current and maximum readings. (b) The tip employed in the
Primary risk factors
assessment of pit and fissure caries. (Courtesy of KaVo.)
Saliva 1. Ability of minor salivary glands to
produce saliva
2. Consistency of unstimulated (resting)
It is, however, possible to assess the likely activity of a saliva
lesion using visual methods, again, on impeccably clean 3. pH of unstimulated saliva
and dry teeth. On smooth surfaces active lesions tend to 4. Stimulated salivary flow rate
be adjacent to the gingival margin, or other plaque stagna- 5. Buffering capacity of stimulated saliva
Diet 6. Number of sugar exposures per day
tion areas (such as a poor restorative margin), and are dull
7. Number of acid exposures per day
in appearance. Running a blunt probe over such lesions Fluoride 8. Past and current exposure
results in a sensation of roughness. Inactive lesions are Oral biofilm 9. Differential staining
often distant from the gingival margin (i.e. achieved during 10. Composition
tooth eruption) and have a surface lustre or shine. Exami- 11. Activity
nation with a blunt probe reveals a smooth, glass-like Modifying factors
surface. Some of these lesions will have discoloured, being 12. Past and current dental status
dark black or brown due to the incorporation of extrinsic 13. Past and current medical status
14. Compliance with oral hygiene and
stain. Obviously these examinations are complicated in the dietary advice
case of pit and fissure caries and those on the inter- 15. Lifestyle
proximal surfaces of teeth. 16. Socioeconomic status
Root surface caries presents initially as well-defined Modified from Ngo H & Gaffrey S (2005) Risk assessment in the
discoloured lesions in areas of plaque accumulation, often diagnosis and management of caries. In: Mount G J & Hume W R
(eds) Preservation and Restoration of Tooth Structure. Sandgate,
close to a recessed gingival margin. Active root surface Queensland: Knowledge Books and Software, pp. 61–82.
lesions are soft or leathery in consistency and may exhibit
a loss of surface contour or cavitation. Arrested lesions 63
Restorative Dentistry
(a) (b)
(c) (d)
Fig. 7.10 The QLF device. (a) The QLF handpiece, with disposable mirror tip. (b) Example of a lesion under normal conditions on the
mesial surface of the maxillary left canine. (c) View of the same tooth under QLF conditions, with tenfold increase in lesion enhancement.
(d) Analysis of this lesion, a coloured map of the degree of demineralisation illustrating that the centre of the lesion is the most severely
effected. This lesion would be amenable to remineralisation therapy. (Courtesy of Inspektor.)
manufactured to measure Streptococcus mutans and a decision on the most appropriate restorative material to
Lactobacillus counts many of which are suitable for use in be used following cavity preparation. Further details on
general practice. Given the function of saliva in clearing the preventative and surgical approach to caries manage-
the mouth of food and debris, as well as its buffering ment can be found in Chapter 8.
capacity, a reduction in salivary flow, due to either disease
or medications, is likely to predispose to caries (Box 7.1).
TOOTH FRACTURE
Following the diagnostic processes and the assessment
of risk, it should be possible to make a decision on the
Tooth fractures are a significant dental problem and are
need (or otherwise) to treat a caries lesion. The decision
reported to be the third most common cause of tooth loss,
not to actively treat should not be interpreted as no treat-
after caries and periodontal disease. The majority of tooth
ment but suggests that the patient is given oral hygiene
fractures are associated with a restoration and are there-
instruction and perhaps dietary advice. In these circum-
fore not the cause of a restoration per se; rather, they are
stances the whole mouth is considered, rather than an
the cause of an enlarged restoration. In a significant number
individual lesion. If active treatment is to take place a deci-
of cases, tooth fracture occurs subgingivally or involves a
sion on whether or not this will include surgical inter-
vertical root fracture and may render the tooth unrestorable.
vention should be reached. If the degree of the caries has
Fractures may be complete or incomplete:
been properly assessed then a non-surgical remineralisa-
tion treatment may be indicated. If surgical removal of • Complete fracture–visible separation at the interface of
64 infected dentine is required this is normally associated with the segments along the line of the fracture
7 / Caries and other reasons for restoring teeth
(a)
(a)
(b)
Fig. 7.11 The electronic caries monitor (ECM). (a) The ECM device
with digital readout. (b) The ECM tip–compressed air is released
during the measurement process. (Courtesy of Lode.) (b)
(a) (b)
Fig. 7.13 Patient reported tenderness of one cusp on biting. The diagnosis was not obvious until the fractured cusp was found to be
separated from the remaining tooth (b).
(a)
Fig. 7.17 Example of severe attrition demonstrating effects on
both upper and lower arches.
ABFRACTION
70
7 / Caries and other reasons for restoring teeth
Extrinsic discoloration
Extrinsic staining may result from two main mechanisms:
those compounds that become incorporated into the pellicle
and produce a stain based on their innate colour and those
that result in a discoloration by chemical interactions at
the tooth surface. Direct staining comes from, for example,
tobacco or dyes from foodstuffs. Additionally, the oral
microflora may contain chromogenic (pigment-producing)
microorganisms which may cause black, brown, green or
yellow/orange stains. Indirect staining is associated with
cationic anti-septics and metal salts. Typically the causa-
tive agent is without colour, or of a different colour to the
resultant stain. An example of this is chlorhexidine. There
is some evidence that suggests that the salivary composi-
(a)
tion of individuals can make them more or less susceptible
to stain. Extrinsic staining may be polished away using
conventional prophylaxis. In certain cases, a more thorough
technique, such as microabrasion, is indicated.
Restorative materials may also discolour intrinsically as
a result of chemical changes occurring following initial set,
but this is an undesirable factor which has largely been
overcome in modern materials. Restorative materials should
ideally have a surface morphology which resists the accu-
mulation of extrinsic stains. The development of stain
around the margins of restorations is usually indicative
of poor marginal adaptation, especially when using tooth-
coloured restorative materials and these should be
polished, repaired or replaced as indicated.
(b)
Internalised discoloration
Teeth may possess either developmental or acquired defects
that result in an increased porosity and thus propensity to
stain. Developmental defects are those described under
‘intrinsic’ staining, but post-eruptively these defects can
acquire further stain. Conditions that cause any form of
enamel hypoplasia are especially prone and exposed
dentine is especially vulnerable to the uptake of dietary
chromogens. Acquired defects result from the use, misuse
and abuse of teeth over their lifetime and include such
things as caries and gingival recession both of which are
associated with an increased uptake of stain. The treat-
ment of this type of discoloration must be determined
(c) after a careful consideration of the aetiology. For example,
inactive, highly stained caries on an occlusal surface would
Fig. 7.24 Examples of tetracycline staining. (a) Mild banding with be treated quite differently to stained dentine following
the stain restricted to mainly cervical areas. This degree of stain
gingival recession.
may be amenable to tooth bleaching treatment, either alone, or
to facilitate the placement of more translucent (and hence
aesthetically acceptable) ceramic veneers. (b) Severe tetracycline
staining from long-term use. The upper teeth have been restored REPLACEMENT OF RESTORATIONS
with veneers but due to their opacity they are aesthetically poor.
Such cases are difficult to treat. (c) Case exhibiting the greyness of
The reasons for replacing restorations are often subjective.
this form of staining. This mild form may respond well to long-
term home use bleaching. Replacement has sometimes been carried out because of
confusion between secondary caries and marginal leakage,
71
Restorative Dentistry
72
8 Restoration of teeth
(simple restorations)
and preventative dentistry
Summary
There is a spectrum of treatment need for any given
lesion; this is not solely based on the severity of the
demineralisation, but on the assessment of a number of
factors including diet, oral hygiene, ability to attend,
attitude to change etc. The clinician must work through
a complex set of decisions before embarking on a poten-
tially destructive restoration, or on a plan of preven-
tative work that may fail, leading to an increased treat-
Fig. 8.4 Range of rinses and gels available for high-and medium-
ment need. Such decisions are influenced by experience
risk patients such as those with reduced salivary flow, or and careful history-taking as well as communication with
removable partial denture wearers. (Courtesy of Colgate.) the patient.
75
Restorative Dentistry
RESTORING TEETH
Box 8.3 Materials used in tooth restoration
76
8 / Restoration of teeth (simple restorations) and preventative dentistry
particle shape does not affect the physical properties of It is the loss of occlusal tooth substance in forming
the set amalgam, but it does affect the handling charac- the occlusal key which predisposes most to the fracture of
teristics, with spherical alloys requiring less force for posterior teeth, especially premolar teeth. This is more of
adequate condensing than lathe-cut alloys. In addition, the a risk if the cavity is a mesial-occlusal distal preparation.
suggested instruments for condensing spherical alloys Retentive cavity features which obviate the need for occlusal
should be of a larger diameter than those used for lathe- keys should be encouraged. It is no longer considered
cut alloys. necessary to extend a cavity into self-cleansing areas in a
buccolingual direction. However, it is essential that an
approximal cavity is prepared through the contact area in
Cavity preparations for amalgam
a gingival direction, given the potential for caries at the
Non-bonded amalgam restorations depend entirely upon contact area (Fig. 8.7). This will also help with matrix
mechanical features built into the cavity preparation to band placement.
achieve their retention. The principles of cavity design for
such restorations are derived from those presented by G.V.
Achievement of resistance form
Black towards the end of the 19th century.
In brief, the principles of cavity preparation following This is intended to produce a cavity which will adequately
removal of caries are as follows: resist occlusal forces, i.e. the cavity floor should ideally be at
a right angle to the direction of the occlusal forces. Further-
• Resistance to displacement in an occlusal direction. more, the cavity should allow for the placement of a suffi-
Originally this was achieved by production of an under- cient depth of restorative material compatible with its
cut cavity, but it is now generally accepted that a cavity physical properties.With amalgam and composite materials,
with parallel, or minimally divergent, walls will suffice. this is generally considered to be approximately 2 mm.
• Resistance to displacement in an approximal direction. For Enamel margins should be finished so that there is no
class II cavities, this is achieved by the production of unsupported, overhanging enamel. Failure to achieve this
occlusal ‘locks’ (Fig. 8.5), or, less frequently, by grooves will result in fracture of the margin if loaded, with the
in the approximal ‘box’ (Fig. 8.6). production of a defect at the cavity margin.
ADHESIVE RESTORATIONS
Resin composite
Basic principles
Composites of polymers and ceramics, known as resin
composites, are now widely used in restorative dentistry Many composites are based on an aromatic dimethacrylate
(Box 8.5). Early materials contained methyl methacrylate, system, such as the monomer Bis-GMA, which is the
but in the mid-1960s, dimethacrylate polymers, such as reaction product of bisphenol-A and glycidyl methacrylate.
Bis-GMA (Fig. 8.8), were developed and used in dental This is a highly viscous monomer which polymerises to
restorative materials. Since that time, considerable develop- form a rigid cross-linked polymer. Because of the viscosity
ment has taken place, especially in the filler technology. Bis-GMA, it is necessary to add diluent monomers to the
Contemporary composite materials are ceramic-filled composite restorative so that its handling is appropriate for
dimethacrylates. These materials are widely used and are intraoral use. A smaller number of composites contain
now finding a growing application in posterior teeth, as urethane dimethacrylate as their principal monomer.
patients increasingly request tooth-coloured restorations, Diluent monomers are typically low-molecular-weight
and as a general alternative to amalgam as concern grows monomers which reduce the viscosity of the material. In
among patients about the use of mercury-containing general, low-viscosity resins have greater polymerisation
materials. shrinkage than high-molecular-weight resins. These low-
molecular-weight resins contribute substantially to the
overall polymerisation shrinkage of the composite material.
A number of manufacturers have recently developed and
Box 8.5 The components of a contemporary composite introduced alternative resin systems to the ‘traditional’
material systems described above.
Principal monomers Early composites, termed macrofilled composites
Bis-GMA (Fig. 8.9), contained fillers of between 5 and 10 μm, but
Urethane dimethacrylate these materials produced restorations which were diffi-
Diluent monomers cult to polish and of poor wear resistance. Microfilled
Ethylene glycol dimethacrylate composites (Fig. 8.10), which contained colloidal silica
Triethylene glycol dimethacrylate (TEGDMA) filler particles of about 0.04 μm, were developed in the
Inorganic fillers mid- to-late 1970s and are still available. Restorations in
Small/large particle fillers (1–7 μm) these materials were easily polished. Current materials
Microfilled fillers (circa 0.04 μm) may contain fillers of lithium aluminosilicates, crystalline
Nanofillers
quartz, or barium aluminoborate silica glasses.The filler in
Silane coupling agents materials designed for use in posterior teeth should be
Initiator/activator components radio-opaque. Many composites contain a combination of
Chemical – benzoyl peroxide
Light cure – α-diketone (camphorquinone and an amine) a barium glass and another filler – these are termed hybrid
composites (Fig. 8.11). Their mean filler particle size is
typically in the range 1–2 μm.
O CH3 O
H2C C C O CH2.CH CH2 O C O CH2.CH CH2.O C C CH2
CH3 OH CH3 OH CH3
78 Fig. 8.8 A dimethacrylate polymer, Bis-GMA, which is the reaction product of bisphenol-A and glycidyl methacrylate.
8 / Restoration of teeth (simple restorations) and preventative dentistry
Physical properties
Contemporary resin composite materials possess adequate
physical properties for all classes of restoration. Wear
resistance is substantially improved in comparison with
Fig. 8.10 Microfilled composites contain colloidal silica filler older materials. These materials do not form a bond to
particles of approximately 0.04 μm.
tooth substance, and an intermediate bonding system is
therefore required. Resin composite materials are generally
supplied in a wide range of shades. Their aesthetic proper-
ties are good.
Stress in composite
The forces generated by polymerisation shrinkage may be
sufficient to damage the bond to dentine, or cause stresses
to develop within the restoration. If the stress exceeds the
adhesive or cohesive strength of the substrates involved,
separation will occur. Stresses are greatest in cavities with
a high ratio of bonded to unbonded surface area (Fig. 8.12).
Fig. 8.11 Hybrid composites typically contain filler particles in the This ratio is termed the configuration factor. The occlusal
range of 1–7 μm with colloidal silica fillers and macrofillers. cavity has the highest area of bonded surface when com-
pared with its unbonded surface (the occlusal surface) and
is therefore the cavity in which, potentially, the greatest
stresses can develop (Fig. 8.12).
Most recently, research has been carried out on the use
Methods to reduce the formation of stresses include:
of nanofillers, which have particle sizes below the wave-
lengths of visible light. Since these nanofillers do not scatter • the use of a material which has a low modulus of
or absorb visible light, they may provide a method for elasticity (e.g. microfill composites)
incorporating radio-opacity into a material without inter- • the use of a flowable composite (see below) of lower
fering with its aesthetics. They may also allow high filler modulus to fill part of the cavity
loading levels to be obtained, with a consequent reduction • slowing the polymerisation of the material by:
in polymerisation shrinkage. – using a light source which gradually reaches maximum
Silane coupling agents (vinyl silane compounds) are intensity over a period of 30 seconds (ramped curing)
incorporated into composite materials in order to bond
the filler particles to the resin. The polymerisation of resin
composite materials may be achieved by chemical means,
using benzoyl peroxide as the initiator. Tertiary amine
activators are also present. However, visible light cure
(VLC) composites which contain an α-diketone such as
camphorquinone and an amine are much more frequently
used. On application of visible light of wavelength
460–485 nm, free radicals are generated, initiating poly-
merisation. Because of the advantage of ‘command’ set,
VLC materials are now widely used. Light sources of
adequate intensity will polymerise most light-cured
materials to a depth of 3 mm.
Causes of undercuring of composites are as follows:
• the light source is not sufficiently close to the material Fig. 8.12 Diagrammatic representation of the various cavity
surface designs. The design at the top left has the lowest ratio of
• the light source is of insufficient intensity unbonded to bonded surface area. 79
Restorative Dentistry
Box 8.7 Properties of glass ionomer cements Box 8.8 Advantages of compomers
• Adhere to enamel, dentine and base metal casting alloys • Generally simple to use and easy to handle
• High compressive strength • Stronger, more aesthetic and less soluble than glass
• Brittle with low tensile strength (therefore not to be ionomer materials
used in load-bearing areas) • Wear resistance is less than resin composite
• Aesthetic properties • Fluoride release is substantially less than glass ionomer
– traditional cements have high opacity materials
– resin-modified cements have satisfactory aesthetics
F- concentration
in solution (ppm)
250
200 Cumulative
amount
150
100
50
0
Amount
released
0 20 40 60 80 100
Time (days)
Fig. 8.14 The amount of fluoride released from glass ionomer materials is high soon after placement but reduces to a constant, lower,
level within 1 week. 81
Restorative Dentistry
small amount of fluoride release which is seen. Early introduction of more heavily filled viscous glass ionomer
compomer materials used a self-etching primer for tooth materials.
conditioning and bonding, but more recent materials have
incorporated a phosphoric acid etching stage prior to
Resin-modified glass ionomer cements
placement. It has been demonstrated that microleakage
is reduced when enamel margins are etched prior to Resin-modified glass ionomers (RMGIs) contain a FAS
restoration placement. glass and poly(alkenoic acid), but also incorporate a
A wide variety of compomer materials are currently monomer such as 2-hydroxyethyl methacrylate (HEMA)
available. Their resin matrices vary. One early material or Bis-GMA. These products set by two mechanisms:
contained an elastomeric resin which added flexibility to
• by the curing of the monomer – light cure or chemical
the bonding mechanism. Another material contains an
cure, or both
acid monomer, termed TCB resin (a bi-ester of 2-HEMA
• by the conventional glass ionomer acid–base reaction.
and butane tetracarboxylic acid). This contains two acidic
polycarboxylate groups and two polymerisable methacrylate These materials will therefore set without light curing,
groups which enable polymerisation by light and an as a result of the acid–base reaction (Fig. 8.15).
acid–base reaction when water is present. Water is taken RGMIs are true glass ionomer materials and are of similar
up to a maximum of 3% by weight in a period of months biocompatibility to conventional glass ionomers, with higher
following placement. This diffuses through the restoration rates of fluoride release and better physical properties, espe-
and an acid–base reaction takes place between the stron- cially with regard to tensile strength.Wear resistance is similar
tium fluorosilicate glass and the polycarboxylate groups of to that of conventional glass ionomers, while the aesthetic
the monomer. This acid–base reaction leads to further properties are better. Applications for RMGIs include core
cross-linking of the matrix and release of a small amount build-ups, restoration of class V cavities, linings and bases.
of fluoride.
Compomers are not adhesive to enamel and dentine,
High-viscosity glass ionomer materials
so an intermediate bonding system must be employed.
Bonding via the systems supplied with compomer mate- High-viscosity glass ionomer cements were developed in
rials produces a hybrid layer similar to that produced by the early 1990s following the introduction of the atraumatic
dentine bonding systems, but there may be some adhesion restorative treatment (ART) technique – a minimal instru-
from an ionic bond to the inorganic part of the tooth. mentation technique designed for less industrialised
Bond strength measurements produce values which are communities (p. 86). These materials, if mixed to the
not as high as with dentine bonding systems to resin-based correct consistency, have high viscosity and may therefore
composite, but retention of restorations in non-retentive be condensed into a cavity in a manner similar to amalgam.
cavities does not appear to be a problem. The mechanical The increased viscosity is a result of finer particle size and
properties of compomers are generally inferior to resin- the addition of poly(acrylic acid) to the powder of some
based composite materials but superior to glass ionomer materials. These materials possess improved physical
materials. Filler loading of a typical compomer is approxi-
mately 70% by weight, and polymerisation shrinkage is
3–4%. A wide variety of shades is available with many
O
systems and, as a result, compomer materials may produce
restorations with good aesthetics. Clinical trial data on the C R
use of compomer materials in class III and V cavities in H2 C
permanent teeth, and in the restoration of primary teeth CH3
CH2
are positive. Copolymerization
C with monomer
O C CH3
Cermets O
In CERamoMETal cements, an ion-leachable glass and
fine silver powder are heated to over 1000°C to form an Methacrylated
amorphous mass which is ground to make a powder that carboxylic acid
is then mixed with a poly(alkenoic acid) to form a set
cement. These materials have similar adhesion to dentine C C
and enamel as do conventional glass ionomers and slightly O OO O
improved physical properties. However, the fluoride release Ca2 Ca2 Adhesion to dentin
is lower. Their applications include core build-ups and
as filling materials for deciduous teeth. However, the value Fig. 8.15 Setting reactions in resin-modified glass ionomer
82 of cermet materials has diminished somewhat since the materials.
8 / Restoration of teeth (simple restorations) and preventative dentistry
Fig. 8.18 Cavity design may be limited only by the need to cut
PLACEMENT OF CLASS II COMPOSITE sufficient access to permit identification and removal of caries,
RESTORATIONS and allow placement of a matrix.
Operation Rationale
Select shade A slight mismatch is desirable in posterior teeth so that cavity margins
can be visualised and enamel damage reduced during finishing
procedures
Check occlusal relationship This is done to visualise the ideal final contour of the occlusal surface,
and it avoids the need for time-consuming removal of excess material
Remove caries; smooth rough or gross
overhanging margins
Extend through contact point in a gingival direction Allows placement of matrix
Obtain isolation, preferably by rubber dam The performance of composite materials is compromised when
contaminated by saliva or blood
Place matrix and wedge A firmly fitting matrix is essential to the correct contour of the restoration
Place base if indicated Bases are only indicated in cavities in close proximity to the pulp
Apply components of dentine bonding system Follow manufacturer’s instructions implicitly
Apply layer of flowable composite to the base A layer of flowable composite will reduce microleakage at the gingival
of the interproximal box and the occlusal margin. Curing in excess of the manufacturer’s suggested radiation
floor and cure for a period in excess of time will ensure proper curing as the layer is furthest from the curing
the manufacturer’s instruction light
Apply increments of composite which only touch Increments placed in this manner may minimise stresses within the final
one wall of the cavity at a time and light cure restoration
Use a non-stick, non-slumping composite which can Achieving a tight contact is essential, but difficult to achieve
be packed against the matrix
Build occlusal contours with incremental build-up. Overbuilding requires removal of excess and costs time
Use sectional matrix and ‘bi-time’ ring
Remove rubber dam
Check occlusion in centric relation and lateral
excursions, adjust as necessary and finish using
composite finishing burs
Apply unfilled resin ‘glaze’ and light cure Re-curing the surface will ensure maximum conversion and optimal
physical properties of the outermost layer of composite. The unfilled
resin will fill any microscopic defects
84
8 / Restoration of teeth (simple restorations) and preventative dentistry
Box 8.9 Causes of thermal sensitivity following Box 8.10 Mounts classification
restoration replacement
This takes account of the site, size and complexity of the
• Direct thermal shock to the pulp as a result of caries lesion:
temperature changes transferred through the (metal) • Site 1 lesions are similar to pit and fissure class I lesions
restoration • Site 2 lesions are those at contact areas:
• Pulpal hydrodynamics due to a space between – size 1 (minimal)
restoration and tooth permitting the slow outward – size 2 (moderate)
movement of dentinal fluid – size 3 (enlarged)
• Bacterial invasion of any space between tooth and – size 4 (extensive)
restoration may result in invasion and inflammation of • Site 3 lesions are those originating close to the gingival
the pulp margin and continuing around the full circumference of
a tooth
Syringe
Bur nozzle
Enamel Glass-ionomer
cement
Caries
Fig. 8.20 The tunnel preparation. (Adapted with permission from Davidson CL, Mjor A, eds (1999) Advances in glass-ionomer cements.
Berlin: Quintessence Publishing Company.)
restored with tunnel cermet restorations is as great as that tooth tissue, including the marginal ridge. Optical aids
of unrestored sound teeth. Other workers concluded that and fibreoptic illumination are required to view the lesion
25% of the glass ionomer and 10% of the cermet tunnel and its preparation satisfactorily. This technique may find
restorations failed, while none of the small amalgam class particular application for patients who have suffered
II restorations placed as controls required replacement. gingival recession, which permits easy access to the lesion
Furthermore, it has been demonstrated that caries is not of caries. As with the tunnel concept, a radio-opaque glass
removed in a proportion of cases. ionomer is most appropriate, so that the proximal area
Anecdotal evidence suggests that this approach is may be checked radiographically for recurrent caries.
technique-sensitive and the use of magnification tech-
niques is essential when carrying out tunnel restorations.
Atraumatic restorative treatment (ART)
Caries detection solutions may also be helpful in ensuring
technique
complete removal of the lesion. Intraoral video cameras
may be helpful in viewing of the preparation. The ART technique was first developed in the mid-1980s,
An alternative approach to the operative management along with interested manufacturers of materials.The concept
of the small proximal lesion of caries may be the ‘lateral’ is based upon hand excavation of caries and the use of an
tunnel or slot preparation (Fig. 8.21), using either a bur or adhesive restorative material and/or sealant. Currently, a
ultrasonic means of preparation. In this technique, the reinforced glass ionomer is employed. ART may be considered
proximal lesion is accessed from the lingual or buccal appropriate for persons living in underdeveloped countries
surface, with the preservation of substantial amounts of and other groups such as refugees. However, ART is only
one component of treatment, which should also include
promotion of other dental health messages such as good
Proximal
caries present oral hygiene and avoidance of cariogenic foods and drinks.
The ART concept has its basis in minimal cavity
preparation and prevention. It may therefore be applied in
the restorative treatment of many child patients, rather
than confining the concept to less industrialised countries.
Proximal view It is also a treatment option for handicapped patients and
of caries lesion
those in domiciliary care.
The ART technique has been shown to be effective,
with results of studies on the longevity of restorations
placed under field conditions using ART with glass
Proximal view ionomer restorations indicating reasonable success rates.
of slot preparation
ART has been well received by the majority of patients.
The principal stages in the ART technique are as follows:
87
9 Management of pulpal
and periradicular disease
Introduction 89 INTRODUCTION
Pulpal and periradicular pathology 89
Pulp disease 90 The field of endodontology has undergone rapid growth over
Soft tissue changes 90 recent years. In particular, there has been a revolution in the
Hard tissue changes 90 technology available for use in treatment. These develop-
Classifiation of periapical disease 90 ments, however, have not changed the fundamental reason
Acute apical periodontitis 90 for treatment, i.e. pulpal and periradicular disease, which is
Chronic apical periodontitis 90 principally bacterial in origin.The aim of treatment is there-
Condensing osteitis 91 fore to eliminate these bacteria from within the root canal
Acute apical abscess 91 system and seal the root canal and tooth to prevent re-entry.
Chronic apical abscess 91
Radiographic lesions of non-endodontic origin 91
Management of pulpal and periradicular disease 91 PULPAL AND PERIRADICULAR PATHOLOGY
Chemomechanical debridement 92
Hand instruments 92 Pulpal or periradicular inflammation results from irrita-
Automated instrumentation 93 tion or injury usually from the following sources:
Irrigation 95
Summary 96
• bacterial
Root canal preparation 96
• mechanical
Access 96
• chemical.
Canal identifiation 97 Bacteria, usually from dental caries, are the main sources
Straight-line radicular access and preparation of injury to the pulpal and periradicular tissues and enter
of coronal two-thirds 98 either directly or through dentine tubules.The link between
Length determination 99 bacteria and pulpal and periradicular disease is well estab-
Apical preparation 99 lished, as in the absence of bacteria periradicular pathology
Rotary nickel titanium instrumentation techniques 101 does not develop. Some modes of entry for bacteria are
One-visit root canal treatment 102 listed in Box 9.1.
Root canal obturation 102
Requirements before root canal filing 102
Properties of root filing materials 102 Box 9.1 Modes of entry for bacteria into the root
Types of root filing materials 102 canal system
Gutta-percha filing techniques 102 • Caries
Under- and overfiling 106 • Periodontal disease (dentine tubules, furcal canals,
Root fracture 106 lateral canals)
The remainder of the seal 106 • Erosion, attrition and abrasion (dentinal tubules)
• Trauma with or without pulpal exposure
Assessment of root canal treatment 107 • Developmental anomalies
Success and failure of root canal therapy 107 • Anachoresis (the passage of microorganisms into the
Management of failed root canal treatment 107 root canal system from the bloodstream)
89
Restorative Dentistry
Examples of mechanical irritation include trauma, chronically inflamed young pulp tissue.Treatment involves
operative procedures, excessive orthodontic forces, sub- root canal therapy or extraction.
gingival scaling and over-instrumentation with root canal
instruments. Chemical irritation may be caused by bacterial
Pulp necrosis
toxins or some restorative materials/conditioning agents,
while periradicular irritation may occur as a result of irri- Pulp necrosis occurs as the end result of irreversible pulpitis
gating solutions, phenolic-based intracanal medicaments and treatment involves root canal therapy or extraction.
or extrusion of root canal filling materials.
CHEMOMECHANICAL DEBRIDEMENT
60
50
50
Change (%)
Other methods of movement include reaming and filing. files is increased in size in order to make this reverse
Reaming infers rotating the root canal instrument clock- balanced force manipulation easier. The increased taper of
wise; this motion draws the instrument into the canal and these files reduces the need for stepping back of 0.02 taper
cuts dentine. Filing infers a linear motion of the instrument instruments to taper the canal preparation.
in a push–pull manner. Filing may be performed around A recent development is the introduction of hand
the perimeter of a root canal, especially if it is oval or ProTaper files (Fig. 9.5). This assortment of instruments
dumb-bell-shaped; such instrument manipulation is includes three Shaper and three Finisher files and they are
termed circumferential filing. described in more detail in the rotary nickel titanium
section (p. 94).They are used by hand in either a continuous
rotations or watchwinding motion. The sequence of use
Nickel titanium (NiTi) alloy files
for the hand ProTaper is as for the rotary ProTaper and is
Root canal instruments have traditionally been manufac- described in Box 9.6.
tured out of stainless steel. Nickel titanium, noted for its
hyperelasticity and shape memory, has radically changed
Automated instrumentation
endodontic file design and instrumentation techniques.
Two features of nickel titanium have proved particularly There is considerable interest in trying to make the
beneficial to endodontics. Firstly, the increased flexibility mechanical aspects of canal preparation easier and quicker.
has allowed files of a taper greater than the standard The most obvious example of this is the use of rotary
0.02 mm/mm used for stainless steel instruments. Such stainless steel Gates-Glidden burs to create space coronally.
variably tapered files range from 0.02 to 0.12 mm/mm. File activation by means of a handpiece to speed up the
A 0.06 taper file, for example, is three times more tapered creation of shape deeper in the canal system is also popular.
than a conventional 0.02 mm/mm file. Secondly, the Historically these have used a reciprocating action or
superior resistance of nickel titanium to torsional failure oscillatory motion (ultrasonic or sonic), but the introduc-
compared with stainless steel has allowed the production tion of nickel titanium has allowed rotary instrumentation
of files that can be used in 360° rotation. to be used over the full canal length in many situations.
Greater taper (GT) files are an example of increased
taper hand files. They are available in a tip size of 20 and
Reciprocating handpieces
have four different rates of taper: 0.06, 0.08, 0.10 and 0.12
(Fig. 9.4). The files all have a maximum flute diameter of Developments in endodontic handpieces include a refine-
1 mm to restrict enlargement coronally. The flutes of the ment of the reciprocating motion to one of 60°, as opposed
files are machined in a reverse direction and a balanced to 90°, which provides a watchwinding type motion. A
force movement is recommended for their use, but in variety of file designs with a latch grip attachment are
reverse, in view of the flute direction. The handle on these available for such handpieces; however, the M4 handpiece
allows root canal files (Fig. 9.6) with conventional handles
to be placed in it. Most instruments for use with the
reciprocating type handpiece are manufactured from stain-
less steel and should be used with a light touch to prevent
Fig. 9.5 Series of hand ProTaper files. Shapers: S1, S2, Sx; Finishers:
Fig. 9.4 Greater taper hand files. F1, F2, F3. 93
Restorative Dentistry
Fig. 9.9 A range of rotary nickel titanium (NiTi) files (from top):
94 Fig. 9.7 The Piezon ultrasonic unit. Orifice shapers, ProFile, Rotary GT and ProTaper.
9 / Management of pulpal and periradicular disease
which has a thin shaft and cutting bud at the end similar It is important that the irrigant is changed frequently.
to a Gates-Glidden bur. ProTaper files offer variable tip Ideally, irrigation should be performed between each file,
sizes but have multiple tapers along their length. at least every two to three files being the minimum. Instru-
mentation of the root canal wall results in the production
of a smear layer. If removal of the smear layer is desired
Irrigation
then an EDTA-containing irrigation solution should be
Irrigating solutions are usually delivered using a syringe used. There is no clinical consensus as to whether or not
with a 27 or 28 gauge needle, as this allows deeper pene- smear layer removal should be practised.
tration into the canal. Care should be taken to ensure that An effective way of delivering irrigating solutions is
the needle does not bind and that irrigating solution does through an ultrasonic handpiece. Ultrasonic agitation
not pass into the periapical tissues. The role of the irrigant (acoustic microstreaming; Fig. 9.11) has been shown to
is to remove debris and provide lubrication for instruments. be effective in removing debris from canals. Sodium
Specifically, an irrigant such as sodium hypochlorite will
dissolve organic remnants and, most importantly, also has
an antibacterial action. This may be used in a range of
concentrations, from 0.5 to 5.25% (2.5% is popular).
Sodium hypochlorite is caustic and can cause damage if
extruded out of the tooth. Typically this will result in pain,
swelling and profuse bleeding. If a hypochlorite accident F
occurs then the patient should be reassured and the tooth
monitored for about 30 minutes. If the exudate continues
to be profuse, then leaving the tooth on open drainage
for 24 hours should be considered. In severe cases, an
antibiotic and analgesic may need to be prescribed.
Fig. 9.10 Lightspeed nickel titanium (NiTi) instrument (top) and Fig. 9.11 Acoustic microstreaming associated with ultrasonic
stainless steel Gates-Glidden bur (bottom). irrigation. 95
Restorative Dentistry
hypochlorite is, however, corrosive and may rapidly cause The ideal access cavity will achieve the key objectives
deterioration of metallic components in handpieces. but will preserve as much sound coronal and radicular
tissue as possible. Occasionally, however, it may be neces-
Summary sary to enlarge and deflect the access to enhance the prepa-
ration of roots that are especially curved in their coronal
The aim of root canal preparation is to debride the pulp thirds. In these situations, access preparation is dynamic,
space, rendering it as bacteria-free as possible, producing developing as instrumentation progresses.
a shape amenable to obturation. This is complicated by
root canal system anatomy, which is complex and makes
complete cleaning impossible. Gross debridement of the Assessment
root canal is performed using hand and automated instru- Access to the root canal system is aided by examination of
ments. These instruments remove infected dentine but the following:
also, most importantly, create space within the canal which
allows the irrigating solutions to work effectively as it is not • coronal anatomy
possible to clean root canals using instruments alone. • tooth position and angulation
• external root morphology
• preoperative radiograph (or preferably more than one
ROOT CANAL PREPARATION
taken at different angles), which affords information on:
– the size of the pulp chamber +/– calcifications
Current thinking on canal preparation emphasises the
– the distance of the chamber from the occlusal surface;
development of shape in a crown-down manner, removing
overlay the access bur to determine the maximum
infected dentine as it is encountered, starting with the
safe depth
access cavity. Further cleaning of the canal is done using
– the angle of exit of root canals from the floor of the
root canal irrigants (in particular, sodium hypochlorite
pulp chamber; this provides an indication of the
because of its antimicrobial and tissue-dissolving proper-
amount of coronal third root canal modification
ties). Root canal preparation involves gaining access to,
required to obtain straight-line radicular access
cleaning and shaping the root canal system. It has both
– the number of roots, degree of root curvature and
biological and mechanical objectives:
canal patency.
• Biological objectives – eliminate the pulp, bacteria and
related irritants from the root canal system
Endodontic access openings
• Mechanical objectives:
produce a continuously tapering preparation Incisor and canine teeth. The access cavities for maxillary
– maintain the original anatomy central and lateral incisors are similar and generally trian-
– maintain the foramen position gular in shape (Fig. 9.12a). Access cavities for maxillary
– keep the apical foramen as small as practical. and mandibular canines are almost identical and more
ovoid in shape (Fig 9.12b). Access for mandibular central
The sequence of canal preparation is as follows:
1. Access
2. Canal identification
3. Straight-line radicular access and preparation of coronal
two-thirds M D M D
4. Length determination
5. Apical third preparation.
Access
Access to the root canal system involves both coronal access
to the pulp chamber and radicular access to the root canals. M D
The coronal access should:
• provide an unimpeded path to the root canal system
• eliminate the pulp chamber roof in its entirety
• be large enough to allow light in and enable examination
of the pulp chamber floor for root canal orifices or fractures (a) (b) (c)
• have divergent walls to support a temporary dressing
between visits Fig. 9.12 Access cavity outline for upper incisor (a), canine (b) and
96 • provide a straight-line path to each canal orifice. lower incisor (c) teeth.
9 / Management of pulpal and periradicular disease
Canal identification
D M M D Knowledge of dental anatomy and undulations in the floor
of the pulp chamber in multi-rooted teeth are used as a
guide. Magnification and coaxial lighting are particularly
useful in helping to identify small root canal openings and
P L to refine access. The pulp chamber space should be
(a) (b) thoroughly irrigated with sodium hypochlorite solution
and canal orifices identified using a straight probe or
Fig. 9.13 Access cavity outline for upper (a) and lower (b) premolar DG16 endodontic explorer. It is useful to remember that
teeth. dentine is yellow/brown in colour, while the floor of the 97
Restorative Dentistry
pulp chamber is grey. Stop and take radiographs if the the canal exploration. Preliminary assessment of the canal
canal(s) cannot be readily located. can be made with the smallest and most flexible
Further refinement of the access may be performed instruments. Frequently the operator will not be able to
following canal identification to enable straight-line access determine the working length initially as files may be
to the canals (Fig. 9.15). In addition, troughing may be binding coronally.
performed using a small long-neck bur or ultrasonic inserts Pre-enlargement is achieved by watchwinding file sizes
to remove dentine overlying canal orifices when looking 10–35 in series, gradually opening up narrow canal orifices
for difficult canals such as second mesiobuccal canals in to a size sufficient to take a Gates-Glidden bur or Orifice
upper molar teeth (Fig. 9.16). Early progress into such shaper.The pre-enlargement can then be developed further
canals is frequently hindered by an abrupt exit from the to produce straight-line radicular access, taking care to
pulp chamber. Careful removal of overlying dentine permits work the drill away from furcal regions of roots. A file
easier access to these canals, which, prior to enlargement should stand upright in the tooth and pass undeflected
coronally, may only allow small files to pass for 2 mm into the apical one-third of the canal once adequate
before impacting on the outer canal wall. straight-line radicular access has been achieved.
The advantages of preparing the coronal two-thirds first
are listed in Box 9.4.
Straight-line radicular access and preparation
Coronal interferences influence the forces a file will
of coronal two-thirds
exert within a canal. This is of particular importance in
Root canals are infinitely variable in their shapes and sizes. curved canals where files may prepare more dentine along
This variation has more effect on canal preparation than the furcal (danger zone) compared with the outer canal
the instrumentation system used. Larger canals allow easy wall. It is important to be aware of this, to limit the size of
placement of instruments and irrigating solutions, whereas enlargement in curved canals and direct files away from
smaller ones require pre-enlargement coronally prior to the furcal wall to avoid a strip perforation (Fig. 9.17).
Gates-Glidden burs may be used to relocate a canal away
from the danger zone, but care should be taken to avoid
over-enlargement. Gates-Glidden burs nos 6 and 5 should
only be used on the walls of the access cavity, and no. 4 no
deeper than the canal orifice.The no. 3 may be used to the
mid-canal region and the no. 2 to the beginning of the
canal curvature, or to near full bur length in a straight
canal. The no. 1 is quite fragile, but may be used at ultra-
slow speeds provided it is loose in the canal.
Apical preparation
It is important to ensure that the apical region of the
canal is not blocked with dentine debris or pulp tissue Considerable debate exists as to where to complete the
when using a crown-down technique. For this reason, apical preparation. Studies have shown that in vital cases
small files with or without chelating agents are used to
prevent blockage and ensure canal patency. Although
apical preparation develops throughout canal enlargement,
it is not completed until the end of the procedure when
greater control is possible over the files in this most
delicate region of the root canal.
Length determination
It is essential that care is taken over identification of
the correct canal length. Clinically, the aim is to identify
the apical constriction, which is the narrowest point of the
root canal; apical to this the canal space widens to form
the apical foramen. Frequently, however, an apical
constriction is not present and thus a more useful
landmark may be the apical foramen.
The most common way of determining canal length is
Fig. 9.18 Electronic apex locators: the Raypex (left) and the Root
using the working length radiograph. A file is placed in ZX (right).
each canal at what is estimated to be the working length.
This estimate of length is obtained by studying the
preoperative radiograph (after adjustment for elongation Box 9.5 Apex locator usage
or foreshortening) and using knowledge of the average
lengths of teeth. Allowances obviously need to be made for 1. Use a file that is large enough to touch the canal wall
in the apical region
fractured teeth and incisal wear. Tactile feel may also help 2. Dry the pulp chamber and most of the root canal prior
in establishing the approximate working length, provided to use
pre-enlargement has been performed. A bisecting angle 3. Check absence of a short-circuit with metallic
radiograph may be taken; alternatively, the film may be restorations
held using a pair of Spencer Wells artery forceps or an 4. Working length is 0.5–1 mm short of 0.0 reading on
apex locator
Endo Ray film holder (the latter two techniques allow for 5. Confirm length on radiograph
radiographs more resembling a paralleling technique to be
performed). The file position is checked on the radiograph 99
Restorative Dentistry
101
Restorative Dentistry
(i) (ii)
(a)
(iii) (iv)
(a) (b)
Fig. 9.22 (a), (i)–(iv) Lateral condensation technique. (b) Radiograph of two canals filled using this technique. 103
Restorative Dentistry
canal slowly to aid coating of the canal walls and reduce simplifying the technique and making it more operator
the likelihood of sealer passing into the periapical tissues. friendly.
If two or more canals are obturated with gutta-percha, The original technique of vertical condensation used
undertake one at a time unless they meet in the apical two types of instrument: a pointed heat carrier that was
third. warmed to cherry-red heat in a Bunsen burner, and a flat-
Once the master cone is seated, a spreader is placed ended plugger that was used cold to condense the thermo-
between it and the canal wall using firm pressure in an plasticised gutta-percha. The introduction of electric heat
apical direction (lateral pressure may bend or break the carriers (Touch and Heat) afforded more control over the
spreader or fracture the root). This pressure, maintained length of time that heat was applied and recently the intro-
for 20 seconds, will condense the gutta-percha apically duction of a more sophisticated thermostatically controlled
and laterally, leaving a space into which an accessory point heat carrier, the System B, has further simplified the tech-
is placed. An accessory cone the same size or one size nique. Two variations in warm condensation of gutta-
smaller than the spreader is used. Rotate the spreader percha exist: the classical interrupted technique, and the
slightly, remove it, and immediately place the accessory recently introduced continuous-wave method.
cone. Repeat the procedure until the root canal is filled. The downpack for both methods is commenced by using
The finger spreader condenses each cone into position; the heat carrier to sear off the gutta-percha master cone at
however, the final cone is not condensed as this would the canal orifice (Fig. 9.23). Immediately following this, a
leave a spreader tract and contribute to leakage. cold, loosely fitting plugger is introduced to condense
The gutta-percha is cut off 1 mm below the cemento- around the periphery of the gutta-percha and seal the
enamel junction or gingival level (whichever is the more canal coronally. A sustained push is now applied to the
apical) using a hot instrument, and vertically condensed centre of the gutta-percha, causing the sealer and warm
with a plugger. It is important not to leave root filling gutta-percha to follow the path of least resistance down
material coronally as it may stain the crown of the tooth. the main canal and along any lateral or accessory canals.
The access cavity should now be sealed, the rubber dam This sustained push is termed a wave of condensation.
removed and a postoperative radiograph taken (Fig 9.22b). In the classical interrupted technique, a series of waves of
condensation are utilised as follows. The heat carrier is
reapplied 3–4 mm into the gutta-percha and removed with
Warm gutta-percha techniques
a small bite of gutta-percha attached. The filling is then
Warm lateral condensation will soften the gutta-percha condensed as described previously to form a second wave
and make it easier to condense, possibly resulting in a of condensation. This cycle is repeated until 5 mm from
denser root filling. The spreader may be heated by placing the canal terminus, or up to the end of the straight part of
it in a hot bead steriliser before insertion into the canal. the canal, and a sustained application of apical pressure is
Alternatively, the friction of ultrasonic vibration may be made as the gutta-percha cools.
used to introduce heat into the root filling. In the continuous-wave method, the downpack consists of
one continuous wave of condensation, rather than several
Thermomechanical compaction involves the use of a
interrupted waves. The appropriate plugger (one of four
compactor, which resembles an inverted file, placed in a
sizes that fits to within 5–7 mm of the canal terminus) is
slow-speed handpiece. The frictional heat from the
selected to match the taper of the canal, and is activated
compactor plasticises gutta-percha and the blades drive
for 2 or 3 seconds as it passes down the canal and condenses
the softened material into the root canal. Care must be
the gutta-percha to just short of its binding point. The
taken only to use this instrument in the straight part of
plugger is then held, applying vertical pressure for 10
the canal in order to avoid gouging of the walls. A
seconds prior to reactivation, which allows the plugger to
modification of the technique has been described as an
drop to its binding point prior to removal together with
adjunct to lateral condensation. First, gutta-percha is
excess gutta-percha.
laterally condensed in the apical half of the canal to
The downpack of both techniques results in obturation
provide apical control, and then a compactor is used to
of the apical third, filling of lateral and accessory canals
plasticise and condense the gutta-percha in the straight
and an empty coronal two-thirds. Backfilling of the canal
coronal half of the canal.
is achieved by delivering increments of thermoplasticised
Vertical condensation of warm gutta-percha involves gutta-percha and condensing them.
applying heat to the gutta-percha, condensing it down the
root canal from coronal to apical (the downpack) and then Thermoplasticised gutta-percha is conveniently delivered
filling the remaining space (the backfill). The procedure using the Obtura gun (Fig. 9.24). Small increments are
aims to seal the terminus of the canal with an accurate placed and condensed in order to keep shrinkage to a
cone fit, and the downpack then forces sealer and gutta- minimum. It is also useful in cases of internal resorption
percha along the lines of least resistance. Significant where the gutta-percha flows into canal irregularities as it
104 changes have been made to the armamentarium recently, is condensed. Care must be taken to ensure that there is
9 / Management of pulpal and periradicular disease
(i)
(a)
adequate apical resistance form to ensure that excess covering of gutta-percha.The size of the carrier required is
gutta-percha is not pushed out of the canal system. checked using a size verification device. The carrier is
placed in the oven provided and heated until the gutta-
Carrier-based systems consist of a solid central core percha is soft. Sealer is placed in the canal, the carrier is
usually made out of plastic (although originally constructed pushed home to the desired length, and any excess is cut
from stainless steel or titanium) which is supplied with a off in the pulp chamber at orifice level. Carrier-based 105
Restorative Dentistry
(a)
(a) (b)
(c) (d)
Fig. 9.29 (a) Radiograph showing persistent lateral lesion associated with upper first molar mesiobuccal root. (b) Mesiobuccal region of
108 pulp chamber. (c) Completion of canal preparation. (d) Radiograph showing re-obturated mesiobuccal root.
9 / Management of pulpal and periradicular disease
(a) (b)
restorative material is rougher than the dentine and this The fracture of a post within a root canal can pose a
can be detected using an endodontic explorer. The access major problem, and care should be taken to try not to
cavity should be thoroughly evaluated at this stage with further weaken, fracture or perforate the root. Such situa-
regard to its extent and the possibility of discovering tions should first be tackled by troughing around the post
previously untreated canals. to remove the luting cement using a small long-neck bur
The removal of a post should not be attempted if the or an ultrasonic tip. As progress is made up the root canal,
force to remove it could result in root fracture. Ultrasonic the smaller suborifice tips may be used.
vibration may be used initially to try to break the cement Use of ultrasonic tips will remove many fractured posts
seal. It is important not to use ultrasound at too high without having to resort to additional means such as the
power as this may produce microcracks in the root or Masserann kit (Fig. 9.30). In this system, a suitably sized
excessive heat, especially if a coolant is not used. In some trepan is directed along the side of the post in the space
situations, ultrasonic vibrations may result in the post created by the ultrasonic tips. A smaller trepan may then
becoming free within the canal. If ultrasonic vibration is be used to grip and remove the fractured portion (addi-
unsuccessful, it is necessary to use a device to pull out the tional ultrasonic vibration applied to the trepan may be
post and core.This can usually be accomplished in anterior useful at this point). If the post is of the screw type, it may
teeth using a post extractor. be unscrewed after the use of ultrasound to weaken the
cement seal either by placing a groove in its end or by
grasping it with a tight fitting trepan.
Access to the apical third of the root is usually restricted
by the presence of materials used to obturate the canal.
Those most frequently used include pastes, gutta-percha
and silver points. A thorough evaluation of the access cavity
should be performed, modifying it as necessary to give
straight-line access to the root canals prior to attempting
removal of the filling materials.
Soft pastes can usually be easily penetrated using short,
sharp hand files and copious irrigation. The use of an
ultrasonically powered file with accompanying irrigation
can be helpful in these situations, especially for removing
remnants of paste from root canal walls, which may remain
despite careful hand instrumentation. Rotary nickel
titanium instruments may also help with removal. Hard
pastes can be particularly difficult to remove (Fig. 9.31)
and usually need to be drilled out with a small long-neck
bur, or chipped out using an ultrasonic insert as described
previously. These procedures can only be used in the
straight part of the canal and it is important to employ
magnification and lighting, as the risk of going off-line and
perforating is high. Irrigation with EDTA and sodium
Fig. 9.32 Gutta-percha removed by Hedstrom file. hypochlorite should be employed together with frequent
drying to ensure good visibility, especially deep within range of sizes and have a safe cutting tip that reduces the
the canal. risk of perforation, provided that too large a size is not
Poorly condensed gutta-percha root fillings may be used. Care should be taken with these drills, because, if
removed by rotating one or two small Hedstrom files too fast a speed is used, they may inadvertently screw into
(Fig. 9.32) around or between the root canal filling points, the canal and cause considerable damage (a suitable speed
pulling and removing them intact. If this is unsuccessful, is around 1000–1500 rpm). Other rotary instruments that
removal of the root canal filling should be considered in may be used for the removal of gutta-percha include those
stages, removing first the coronal and then the middle and made from nickel titanium, which are extremely efficient
apical thirds. Gates-Glidden drills may be used coronally in this respect. They may be used with care at higher
in the straight part of the canal. These are available in a speeds (up to 700 rpm) than for canal preparation.
(a) (b)
If gutta-percha removal is being attempted around a this region. If this is not possible, the canal should be
curvature, it is important to use a solvent such as chloro- shaped, irrigated and obturated to the level of the frac-
form, oil of cajaput or oil of turpentine to soften the gutta- tured instrument, as in vital uninfected cases success rate
percha, aid mechanical removal and reduce the chance of will frequently not be affected (Fig. 9.37). However, if the
transporting the main axis of the canal. Chloroform is the root canal system is infected then the fractured instrument
most effective solvent for dissolving gutta-percha. may preclude thorough debridement of the root canal
The seal of silver point root canal fillings is rarely as system. In such situations, prognosis is compromised.
good as the radiographic appearance would suggest, and Frequently after removal of filling materials or broken
in many cases relies on the cement used. If this washes instruments, a ledge will be noted in the side of the root
out, then corrosion will occur leading to failure of the root canal.This may usually be bypassed by placing a sharp bend
canal filling.The approach to removal depends on whether at the tip of a small file. The ledge may then be smoothed
the point extends and can be seen to extrude within the using a linear filing motion. Shaping and irrigation of the
pulp chamber. In such situations, many silver points can canal system can then be completed prior to canal obtura-
be removed easily by grasping with Steiglitz forceps or pin tion. Canals may also be blocked; in such situations, the
pliers and levering (Fig. 9.33). If the points cannot be access cavity is refined and a small sharply curved file is
removed easily, ultrasonic vibrations can be applied to the used to pick around the blockage. Frequently the coronal
forceps holding them. part of the blockage is denser and once this is penetrated
If the silver point has been cut off at the canal orifice, rapid progress may be made to the apex. On occasions it
it is usually not possible to grip it. In such situations, an may not be possible to unblock a canal and care must be
ultrasonic tip may be used to cut a trough around the taken not to over-instrument and create a perforation.
point; care needs to be taken not to touch the point as the The success of root canal retreatment is good (94–98%)
silver is much softer than the steel used in the manufacture when it is being undertaken to achieve a technical improve-
of the ultrasonic tip and preferential removal of the point ment in potential failures. When periradicular pathology
will occur. A Masserann extractor (Fig. 9.34) can be used is present, the success rate is much lower (62–78%).
to grip the point and remove it once a trough approximately Retreatment itself can bring its own problems: perforation,
2 mm deep has been prepared. separated instruments and compromised cleaning and
Sometimes it may be necessary to work an ultrasonic obturation of the canal system. It is important that patients
spreader tip down the side of a point placed deep in a root are informed of such factors prior to embarking on this
canal. Removal in these situations may be facilitated by procedure.
placing a Hedstrom file along the side of the point and
pressing it into the soft silver in order to help pull it
Apical surgery
coronally (Fig. 9.35). Occasionally it may help to apply
ultrasonic vibrations to the Hedstrom file prior to pulling. Apical surgery is an alternative to root canal retreatment.
However, conventional orthograde root canal treatment
Instrument fracture. The separation (fracture) of root is preferred to surgery if at all possible, even if it is
canal instruments is a procedural hazard in root canal considered that surgery may be necessary. It must be
therapy. File fracture may be minimised by: remembered that the main cause of failure is inadequate
debridement and bacterial contamination of the root canal
• maintaining a good quality control programme
• discarding any damaged instruments
• not forcing instruments
• using instruments in the correct sequence
• not rotating stainless steel instruments more than a
quarter turn clockwise.
The removal of fractured instruments has traditionally
been performed using Masserann trepans and extractors
together with ultrasonic vibration. New developments in
ultrasonic tip designs, the use of magnification and lighting,
and in particular the operating microscope have simplified
instrument removal (Fig. 9.36). Loupes and a headlamp
will help in the removal of superficially placed instruments.
If working deep within the canal, it is advisable to use the
operating microscope, especially if using ultrasound.
It may be possible to bypass a separated instrument
which cannot be removed. This becomes more difficult
112 apically as the canal is usually rounder in cross-section in Fig. 9.36 Photograph of operating microscope.
9 / Management of pulpal and periradicular disease
(a) (b)
Fig. 9.37 (a) Fractured rotary nickel titanium instrument in mesial root of a lower molar. (b) Radiograph following instrument bypass and
obturation.
system; hence the importance of root canal retreatment Ideally, surgery should only be performed on cases that
whenever possible. On occasions, however, retreatment of are considered hopeless. Such situations may include large
a tooth may involve the removal/destruction of expensive posts, sclerosed canals and broken instruments. Further
crown and bridgework. In such situations, a patient may important indications for periradicular surgery include
opt for a surgical as opposed to an orthograde approach. obtaining tissue for a biopsy or examination of the root
This should only be undertaken if the patient understands surface to check for root cracks/fractures.
that dismantling of restorations may be necessary in the
future, should the surgery fail.
113
10 Restoration of teeth
(complex restorations)
Dental amalgam
Amalgam has adequate mechanical properties for many
core build-up situations. It is radio-opaque and has been
shown to have superior cariostatic properties to com-
Fig. 10.1 Core build-up of lost coronal tooth structure. posites. It has high thermal conductivity and coefficient of
thermal expansion. It is not adhesive to tooth structure,
although methods of bonding amalgam using resin adhe-
abutments for fixed or removable prostheses are subject to sives are available, and glass ionomer/resin ionomer cements
increased stress. show promise. Conventional dental amalgams set too
The restoration of severely broken down teeth is an slowly to allow tooth preparation during the same visit as
increasing problem for the restorative dentist, as more core build-up. Modern fast-setting spherical alloys may
patients retain their natural teeth into older age. Clinical allow preparation 20–30 minutes after placement. Silver
studies demonstrate an increased incidence of tooth frac- amalgam has been reported to be the most reliable direct
tures in teeth with large restorations compared with sound core build-up material under simulated clinical conditions
or minimally restored teeth. because of its high compressive strength and rigidity
Whilst advances in adhesive restorative materials and (Fig. 10.2).
techniques may result in more predictable retention of
restorations with compromised retention, the success of
these techniques is still to be confirmed by clinical trials. Box 10.1 Desirable properties for a core material
Such techniques may be operator-sensitive as the success
• Compressive strength to resist intraoral forces
of an indirect restoration depends on the ability of the • Flexural strength to prevent core dislodgement during
cement or resin lute to prevent dislodgement of the function
restoration from the tooth preparation; the latter must • Biocompatibility with surrounding tissues
possess adequate retention and resistance form. Whilst • Ease of manipulation
resistance form is considered more critical than retention • Ability to bond to tooth structure, pins and posts
• Capacity for bonding with luting cement or having
form, it is impossible to separate these two features. Reten- additions made to it
tion will prevent dislodgement of the restoration along a • Coefficient of thermal expansion conductivity similar to
direction parallel to its path of insertion, whilst resistance dentine
prevents dislodgement in any other direction. Minimal • Dimensional stability
taper and maximum preparation height are critical features • Minimal water absorption
• Short setting time to allow tooth preparation and core
for good retention. The fit of the restoration, any surface placement to be carried out during the same visit
treatments which facilitate adhesion, and the nature of • No adverse reaction with temporary crown materials or
the cement lute are also important variables. If adequate luting cements
retention and resistance form can be developed from • Cariostatic potential
natural tooth structure, the strength of any core or founda- • Low cost
• Contrasting colour to tooth tissue unless being used for
tion restoration is less critical and minor depressions or anterior cores
undercuts in the tooth preparation can be restored with
116 adhesive restorative materials.
10 / Restoration of teeth (complex restorations)
missing, and where increased tooth strength and abutment mised teeth. In clinical situations, flat one-surface cavity
retention are not required. designs occur infrequently and it is often possible to create
steps or varying levels within a preparation increasing
retention and resistance to occlusal forces. Other methods
PREOPERATIVE ASSESSMENT (Table 10.1)
of increasing retention and resistance without having to
resort to pins include circumferential slots, amalgapin
Restorability of tooth
channels or ‘pot-holes’ and peripheral shelves.
The extent of caries and the existing restorations should Spherical alloys are best suited to condensing into small
be assessed. When teeth are prepared for crowns there is retentive features of a cavity preparation and suitable
often amalgam remaining in proximal boxes, class V areas small-diameter condensers are required. Slot-retained
and other regions. All previously placed materials should restorations are more sensitive to dislodgement during
be removed (unless the operator has recently placed the matrix removal than pin-retained restorations. Occasionally,
restoration and is sure it is reliably retained to sound tooth when minimal tooth structure remains for mechanical
tissue), allowing teeth to be rebuilt without the risk of retentive features, pins may be required to supplement
an insecure foundation or previous pulpal exposure retention. The amount of remaining coronal tooth struc-
remaining undetected. If more than 50% of the coronal ture (not undermined) is assessed after removal of caries
tooth structure is remaining and there is no requirement and old restorations. Unsupported tooth structure may
for increased tooth preparation strength, then a bonded need to be removed if the build-up is to serve as a direct
compomer or resin ionomer base may be used to restore permanent load-bearing restoration. Retention of thin
the tooth to the ideal preparation form. If ≥50% of the slivers of unsupported tooth structure may, however, be
coronal tooth structure has been lost and there is not a appropriate if the build-up is to serve as a foundation for
minimum of 2 mm sound tooth structure circumferentially a crown.
gingival to the tooth preparation, a high-strength (bonded
amalgam or composite) core build-up is required to increase
Pulpal/endodontic status
tooth strength and aid crown retention/ resistance form.
Mechanical retention in teeth may be increased by: Prior to core build-up, an assessment should be made
of the pulpal status of the tooth in question. If the pulp
• grooves
is exposed or there are signs/symptoms of irreversible
• boxes
pulpitis, endodontic treatment should be performed. In
• dovetails
the case of an endodontically treated tooth, the quality
• converting sloping surfaces into vertical and horizontal
of the treatment should be assessed radiographically
components
(Fig. 10.4). If the treatment is considered inadequate, a
• reducing/covering undermined cusps.
decision will need to be taken as to whether there is
The use of pins and posts should only be considered as potential for retreatment or whether the tooth would be
a last resort as they will further weaken already compro- better extracted.
118
10 / Restoration of teeth (complex restorations)
(a)
CROWNS
vertical walls of the cavity and their degree of convergence. odontal condition has been stabilised and their caries risk
Only when the restoration is adhesively luted with a resin- is low.
based luting cement combined with an enamel/dentine The restorative assessment of the individual tooth involves:
adhesive is the luting agent a major contributor to retention. • sensitivity/vitality tests
Indirect restorations may be: • long cone periapical radiograph
• intracoronal (inlays) • examination of the quality of any existing restorations
• extracoronal (crowns) • assessing whether the remaining tooth structure after
• a combination of intra- and extracoronal (onlays). preparation will have sufficient strength
• assessing the need for crown lengthening prior to treatment
Restorations may be: • occlusal considerations.
• wholly metallic (precious or non-precious alloys) The occlusal assessment should involve consideration
• ceramic/composite of the tooth position relative to the opposing as well as the
• a combination of the above (metal-ceramic crown). adjacent teeth, as this will influence preparation design. If
there are occlusal interferences, these may place such a
Crowns may cover all available surfaces of the tooth (full
crown under high functional stresses and will require
veneer crowns), or they may be partial veneer (e.g. three-
removal at a prior visit.The surfaces of the crown will need
quarter or seven-eighths crowns).
to be duplicated so that either the group function or
The stages in the clinical procedure involved in an
canine guidance occlusion is maintained.
indirect restoration are usually as follows:
The tooth may be a key unit in the arch, i.e. partial
1. Decision as to restoration type (full or partial coverage; denture abutment, and the shape of the surface should
intracoronal or extracoronal), materials and method be modified to allow the subsequent placement of the
of luting (conventional cementation or bonding with a denture. In such situations, mounted study casts are a
resin-based luting material) useful aid in planning the preparation design as well as
2. Discussion with patient before tooth preparation stage carrying out the occlusal assessment.
as to type of restoration and aesthetic implications Any tooth preparation for a crown should follow the
3. Tooth preparation (this may require prior occlusal appropriate biomechanical principles (Box 10.3), and when
adjustment or diagnostic wax-up to facilitate production planning replacement of a failed indirect restoration, it is
of provisional restoration) important to identify the cause(s) of failure so that this
4. Fabrication of temporary/provisional restoration may be corrected at the time of preparation.
5. Impressions and occlusal records Common causes of failure include:
6. Shade selection
• poor preparation design/shape resulting in lack of reten-
7. Try-in
tion and/or resistance form
8. Cementation or bonding.
• insufficient reduction or lack of support/thickness for
ceramic or composite
PREOPERATIVE PLANNING • undercut preparations
• failure to identify and/or correct occlusal problems
122 Before considering embarking on indirect restorations, • poorly fitting restorations resulting from poor impres-
patients should be assessed to ensure that their peri- sion procedures or faulty laboratory technique
10 / Restoration of teeth (complex restorations)
• When opposing teeth occlude on the cervical fifth of (1.5 mm) is required to allow for both the metal sub-
the palatal surface. structure and metal overlay. These crowns are frequently
over-contoured due to inadequate tooth reduction. Heavy
Porcelain jacket crowns are finished to a shoulder or tooth preparation to achieve adequate thickness for both
butt joint margin design unless the preparation is to be materials may result in an increased incidence of pulp
bonded (dentine-bonded crowns). All-ceramic crowns are death. If this is a risk then a bevelled shoulder or cervical
preferred to metal ceramic crowns on post-crowned teeth chamfer may be preferred to the conventional full 1.5 mm
where there is a risk of trauma. In this case, the weaker axial reduction in cases where the tooth preparation has to
porcelain jacket crown fractures rather than the stress be extended down onto root surface or where there is a
being transferred via the post core leading to root fracture. large pulp. Metal occlusal coverage is generally preferred
to maximise retention and resistance form and to mini-
mise tooth reduction. Metal occlusal contacts are easier
Indirect composite
to create and adjust. Porcelain occlusal surfaces are more
Laboratory composites with improved strength and wear aesthetic but demand additional tooth reduction and
resistance are now commercially available and are increasing create the risk of excessive occlusal wear of opposing tooth
in popularity. Coupled with improvements in resin-based surfaces (Fig. 10.14).
luting cements and dentine bonding systems, indirect com-
posite restorations (with or without fibre reinforcement)
Indications for use
may be considered appropriate for single unit inlays, onlays
and crowns (Fig. 10.13). • Anterior teeth where there is insufficient space for an
Laboratory composites are generally preferred to porcelain all-ceramic restoration
restorations for inlays, whereas the latter offer more permanent • Repeated failure of porcelain jacket crowns (identify
form stability in onlay and crown situations. Some prefer a reason first)
material which is less wear-resistant and as such is sacrificial • Posterior crowns where aesthetics is important and full
in nature to a highly wear-resistant ceramic restoration which or partial veneer gold crowns are contraindicated on
may ultimately cause excessive wear of the opposing dentition. this basis.
Table 10.3 Clinical and laboratory techniques for aesthetic inlays (stages 1 and 2)
Operation Rationale
Stage 1
Impression technique As for a gold inlay
Laboratory instructions Request for etching of the fitting surface of ceramic inlays with
hydrofluoric acid to provide a micromechanically retentive fitting
surface
The fitting surface of composite inlays are sandblasted as the achievement
of a micromechanically retentive fitting surface is more difficult
A silane bond enhancer should be applied to both ceramic and
composite inlays both in the laboratory and also prior to cementation
Temporary restoration The temporary restoration should be constructed in a light or chemically
cured provisional material and cemented with a eugenol-free
temporary luting material.
Stage 2
Remove temporary and clean cavity with pumice Removes contaminants such as eugenol
Handle inlay with care, try into cavity: do NOT Inlay is weak prior to cementation
check occlusion
If satisfactory fit, clean inlay fitting surface with Fitting surface may have been contaminated with salivary pellicle
phosphoric acid for 15 seconds
Apply silane bond enhancer to inlay fitting Silane will improve adhesion of resin to ceramic inlay by circa 20%
surface and allow to evaporate
Isolate, preferably under rubber dam Saliva and/or blood contamination will reduce bond strength
Apply matrix, or organise alternative means for Excess luting material will cause gingival irritation
removal of excess luting material at gingival
margin, such as floss and Superfloss
Mix luting material and apply to cavity Application of luting material to inlay may result in fracture of inlay
Place inlay slowly and carefully Rapid insertion of the inlay may result in its fracture
Remove excess luting material from accessible Removal of excess luting material is much more difficult when it has
surfaces with sponge pellets or equivalent, and been cured
interproximal excess with a probe or floss if a
matrix has not been placed
Cover margins with anti-air-inhibition gel This will allow full polymerisation of the lute and prevent removal
of the uppermost layer when finishing margins
Light cure from all directions in excess of It is not possible to overcure a composite and light is absorbed by the
manufacturer’s suggested timing inlay, especially if a dark shade has been chosen. Physical properties
of dual-cure materials are better when light-cured
Finish margins, check occlusion in all positions, Smooth margins will not retain plaque
and polish
resin composite-based luting material, with the bond being bonded to the underlying tooth. Indeed, since feldspathic
mediated by the use of a dentine bonding system and a porcelain is often used as the outer ceramic layer in
micromechanically retentive ceramic fitting surface. Appro- many restorative modalities, such as metal-ceramic or
priate ceramics include feldspathic porcelain and aluminous aluminous porcelain, in the dentine-bonded crown tech-
porcelain, but any reinforced ceramic (e.g. Empress: Ivoclar- nique, the tooth acts as the core, bonded to the ceramic
Vivadent, Leichtenstein) may also be appropriate provided by way of the dentine bonding agent and luting material
that it is possible to etch its fitting surface with hydro- (Fig. 10.19).
fluoric acid or a hydrofluoric/hydrochloric acid mixture Advantages and disadvantages of dentine-bonded
to produce a micromechanically retentive fitting surface. crowns are as follows:
The bond between ceramic and resin luting material
is enhanced by application of silane to the fitting surface. Advantages
As with ceramic inlays, these crowns are weak until • Good fracture resistance 127
Restorative Dentistry
(a)
• Achievement of good aesthetics
• Minimal axial preparation results in less pulpal irritation
(occlusal/incisal reduction is as for a porcelain jacket
crown)
• Reduced potential for microleakage
• Use in situations where preparation taper is large or
crown height poor
• Luting material is virtually insoluble in oral fluids
• Use in patients who are sensitised to any constituent of
casting alloys
• Correctly finished, they should not cause irritation of
the periodontal tissues
• No marginal gap as this is filled with the luting material.
Disadvantages
• Problems of isolation for the bonding procedure if deep (b)
subgingival margins are present Fig. 10.19 (a) Dentine-bonded all-ceramic crowns constructed in
feldspathic porcelain on central incisor teeth. (b) Preparation for
• The luting procedure is more time-consuming than for crowns illustrated in (a) shows minimal shoulder and less tooth
conventional crowns, resulting in a higher chairside cost reduction than for conventional crowns. (Reproduced by courtesy
• Lack of extensive long-term clinical data on effectiveness. of George Warman Publications, of Dental Update.)
Dentine-bonded crowns are indicated:
• as replacements for failed, conventional crowns • introduction of Bis-GMA resins and the subsequent
• in cases of tooth wear development of resin composite luting materials
• as alternatives to metal-based alloys. • surface treatments which provide a micromechanically
They are not suitable where isolation is not possible, retentive ceramic fit surface.
such as deeply subgingival margins or in patients with
uncontrolled caries or severe parafunctional habits.
The placement technique for dentine-bonded crowns is
outlined in Table 10.4.This has been considerably simplified
by the introduction of self-adhesive resin luting materials
such as RelyX Unicem (3M ESPE, Seefeld, Germany) which
obviate the need for separate etching and bonding stages.
Operation Rationale
Remove temporary and clean preparation with pumice Removes contaminants such as eugenol
Handling crown with care, try into preparation; do NOT Crown is weak prior to cementation
check occlusion
If satisfactory fit, clean fitting surface with phosphoric Fitting surface may have been contaminated with salivary
acid for 15 seconds pellicle
Apply silane bond enhancer to fitting surface and Silane will improve adhesion of resin to crown by about 20%
allow to evaporate
Isolate, preferably under rubber dam Saliva and/or blood contamination will reduce bond strength
Organise means for removal of excess luting material Excess luting material will cause gingival irritation
at gingival margin, such as floss and Superfloss
Apply dentine-bonding agent in thin layer to dentine Provides adhesion of resin luting material. Thin layer essential as
surface pooling at internal line angles will prevent seating of crown
Mix luting material and apply to crown Must be handled carefully
Place crown slowly and with care Rapid placement may result in fracture of thin margins
Remove excess luting material from accessible surfaces
with sponge pellets or brushes, and interproximal
excess with a probe and/or floss; run Superfloss
through at gingival margin
Cover margins with anti-air-inhibition gel This will allow full polymerisation of the lute and prevent
removal of the uppermost layer when finishing margins
Light cure from all directions in excess of manufacturer’s It is not possible to overcure a composite and light is absorbed by
suggested timing the crown, especially if a dark shade has been chosen. Physical
properties of dual-cure materials are better when light-cured
Finish margins, check occlusion in all positions, and polish Smooth margins will not retain plaque
These major discoveries, coupled with the continued • Extrinsic permanent staining not amenable to bleach-
evolution of laboratory techniques (platinum matrix build- ing techniques.
up technique for porcelain laminates; refractory invest-
ments; new ceramics with optimised properties specific In addition, discoloured non-vital teeth that otherwise
to porcelain laminates) and materials/clinical procedures might require post crowns can be veneered (perhaps after
(porcelain etching gels; stable silane solutions; veneer internal bleaching has been attempted). Whilst PLVs may
bonding composites/specific instrument kits for tooth afford a more conservative alternative to post crowns
preparation and establishment of appropriate preparation in these situations, these restorations may appear darker
criteria), have made porcelain laminate veneers a well- in time as the root-filled tooth is liable to colour change.
established and predictable treatment modality. External bleaching through the palatal surface of the
natural tooth (or internal bleaching) may reverse this
situation (Fig. 10.21).
Indications
Porcelain laminate veneers may also be used to correct
Porcelain laminate veneers can be used in a variety of clinical peg-shaped lateral incisors, to close proximal spacing and
situations. For example, colour defects or abnormalities of diastemas, to repair (some) fractured incisal edges, and
the enamel, such as the following, can be masked: to align labial surfaces of instanding teeth. Any closing of
diastema must take the overhanging porcelain/occlusal
• Intrinsic staining or surface enamel defects caused by: guidance relationship into consideration, since this involves
– physiological ageing the risk of fracture. Converting a canine to the shape of
– trauma a lateral incisor (in the case of a missing lateral) usually
– medications (tetracycline administration) requires a partial veneer crown (reverse three-quarter)
– fluorosis preparation. When major changes to the shape of the teeth
– mild enamel hypoplasia or hypomineralisation are planned, it is advisable that a diagnostic wax-up on
– amelogenesis imperfecta a study cast is carried out first. Alternatively, mock-up
– erosion and abrasion facings of composite or porcelain may be made on a cast 129
Restorative Dentistry
of the unprepared teeth for chairside and/or intraoral presence of small labial or proximal restorations may not
evaluation by the operator or patient (Fig. 10.22). contraindicate veneers.
When lower incisor teeth meet in close apposition to
the palatal surfaces of opposing maxillary incisors, the
Contraindications
occlusal forces are less favourable and the available bond-
Veneers are contraindicated when there is a poorly motivated ing area is often considerably reduced. Where it is seen
patient with a high caries rate and appreciable amount of that veneers are more difficult to place, they should only
periodontal destruction. Recession, root exposure (with be considered when all other alternatives are unacceptable
discoloration) and a high lip line are other contraindications. to the patient.
PLVs are normally contraindicated if the preparation Another situation in which PLVs may not be appro-
does not preserve at least half of the surface area remain- priate is when teeth are severely discoloured. Opaque
ing in enamel or if it has to be extended onto cervical root porcelains and luting cements can be used but the end
structure. A more extensive restoration such as a metal- result may be a dull, ‘lifeless’ over-contoured restoration
free dentine-bonded ceramic crown or a conventional high- with poor cervical appearance because the veneer can only
strength porcelain jacket crown may be more appropriate be extended onto the enamel-covered crown surface. It is
in these situations. difficult to achieve a good aesthetic result on a single, very
Labially positioned, severely rotated or overlapped teeth discoloured tooth with a PLV and, in such cases, a crown
will prove difficult to restore with veneers (Fig. 10.23), as restoration may be more appropriate.
will teeth in which there is loss of substantial amounts of
structure, including labial enamel, and those with inter-
Design considerations
proximal caries or unsound/leaking restorations. The
Teeth can be veneered without any preparation (e.g. an
instanding upper lateral incisor) but this is generally not
favoured as it will result in over-contouring (complicating
plaque control) and the restoration may be difficult to
locate accurately on cementation. Indications for a ‘non-
preparation’ approach include patients who are averse to
having any tooth preparation (they must have the impli-
cations of this fully explained to them in advance and this
must be recorded in the notes).
Removal of surface enamel makes resin–enamel bond-
ing more effective. The presence of small labial or proximal
restorations may not contraindicate veneers. They may
be incorporated into the preparation and they should be
replaced before or during veneering to ensure caries
removal, effective bonding and good marginal seal. Restora-
tion with glass ionomer cement rather than composite
130 Fig. 10.22 Diagnostic wax-up of teeth. resin may be indicated.
10 / Restoration of teeth (complex restorations)
required to achieve a favourable restoration contour when protect part of the palatal surface, or when the incisal edge
there are diastemas to be masked or when there is caries is poor aesthetically due to minor chipping etc. Incisal
or an existing restoration proximally. reduction must provide a minimum ceramic thickness of
at least 1 mm. A thicker layer should be used for canine
teeth and lower incisors. The lingual margin placement for
Incisal coverage
a lower incisor may be extended one-third of the way
The veneer is extended to or taken over the incisal tip down the lingual surface, transforming the veneer in effect
depending on the need to rebuild or lengthen this area into a partial crown. With this type of preparation the
(taking into account occlusal constraints). An incisal bevel ceramic will be exposed mostly to compressive stresses
is the preparation of choice when the tooth to be veneered and less to flexural stresses. Despite the small preparation
is of the correct length and the anticipated functional surface area, the failure rate is relatively low. The degree of
occlusal loads will be low. If the occlusion permits, the extension onto the lingual/palatal surface will depend
incisal edge of the tooth should not be routinely covered upon the particular clinical situation. The lingual finish
as the preparation is then more conservative and does not margin should be prepared as a hollow ground chamfer to
alter the patient’s natural incisal guidance/tooth contacts. a depth of 0.5–0.7 mm. This margin should be located
However, when the incisal edge of the tooth is not over- away from centric stops or areas of direct occlusal impact.
laid, the occlusal third of the PLV is often very thin (0.3 mm
or less). If there is edge-to-edge occlusion or evidence of
Impression
incisal wear then there is a greater risk of chipping or incisal
fracture of the veneer from occlusal load (Fig. 10.25). A silicone impression taken in a full arch stock impression
In addition, when the teeth are thin, the difference in tray is adequate. Alternatively, a twin-mix single-stage
resilience between the prepared natural tooth and the PLV addition-cured silicone impression taken in a special tray
can, under occlusal load, lead to cracking or fracturing of may be used. Occlusal stops should be placed on teeth away
the ceramic. A similar consideration applies if extensive from those prepared. Retraction cord placement is rarely
composite restorations are present. necessary and, if required, may indicate overpreparation.
Complete coverage of the incisal edge with a minimum Simply blowing with an air syringe should reveal the
thickness of 1 mm of ceramic (preferably 1.5 mm) will offer margin in the final preparation. Gingival retraction,
the following advantages: however, is required to record the root emergence profile
when the cervical margin is placed equigingivally or sub-
• It restricts incisal fracturing in cases of heavy occlusal load. gingivally for aesthetic or other reasons. Non-medicated
• It facilitates changes in tooth shape/position. retraction cords (small braided cords – Ultrapak No. 1 or
• It facilitates handling and positioning of the PLV at try- No. 2, Ultradent) are preferred to reduce any risk of
in and during bonding.
gingival recession. Any undercuts created by the cervical
• It allows the veneer margin to be placed outside the embrasure spaces may be filled in lingually with softened
area of occlusal impact.
wax to avoid the risk of the impression tearing.
• It facilitates achievement of good aesthetics in the final
restoration.
Temporary cover
An incisal edge overlap preparation is used when tooth
lengthening is indicated, when it is necessary to cover/ This is rarely indicated for minimal veneer preparations
and, when required for a single veneer, can be accomplished
with light-cured composite resin build-up.The tooth prepa-
ration is coated with a layer of water-soluble separator
(glycerin), light-cured composite restorative is applied and
excess removed from interproximal spaces before curing.
After light curing, the hardened material may be removed
for shaping and polishing. It may be cemented to the tooth
surface with a layer of composite after the preparation has
been spot-etched centrally (Fig. 10.26).
Pairs of veneer preparations may be made at the chair-
side or in the laboratory on a quick-setting plaster cast
poured from an impression. Multiple temporary veneers
may be made at the chairside with the aid of a transparent
vacuum-formed plastic mould prepared from a model in
the laboratory. A light- or chemically cured provisional
composite resin may be used to make the provisional
132 Fig. 10.25 Incisal preparation for porcelain laminate veneer. veneers. After trimming and adjustment, the veneers may
10 / Restoration of teeth (complex restorations)
(a)
Fig. 10.26 Spot-etching of UR1 prior to temporary coverage for
porcelain laminate veneer.
Finishing
Gross excess cement can be removed with hand instru-
ments such as scalers and composite finishing burs.
Remove residual excess from the margins with water-
cooled composite finishing burs which may also be used
for fine trimming of porcelain margins. The gingiva is
protected by retraction with the blade of a ‘flat plastic’
hand instrument and the proximal area is finished with
composite finishing strips. The contact point should be (b)
checked so that it allows floss to pass between smoothly. Fig. 10.28 Final finishing of veeners.
The finished result is shown in Figure 10.28.
The final polish of margins is undertaken with impreg-
nated polishing discs and cups (Enhance-Dentsply),
polishing pastes (Prisma-Gloss/Dentsply) and/or composite adjusted if required. It is known that properly executed
polishing discs (Soflex 3M). A final check is made on the porcelain veneers rarely fail due to bond failure. However,
occlusion and the PLV is adjusted to remove premature a mouth guard should be provided for contact sports
contacts in all excursions. players to avoid damage.
134
11 Treatment of tooth
substance loss
Incidence of tooth substance loss 135 REASONS TO TREAT TOOTH SUBSTANCE LOSS
Reasons to treat tooth substance loss 135
The history 136 Treatment of TSL may be required for a variety of
The examination 137 reasons:
Treatment of tooth substance loss 138
Classifications for treatment of TSL 138
• The patient may request it because of poor aesthetics of
the worn teeth or because of sensitivity or pain.
Treatment of category 1 patients 138
Treatment of category 2 patients 139
• There may be infections associated with teeth which
have become non-vital as a result of severe TSL.
Treatment of category 3 patients 140
Types of restoration 140
• Patients may also complain of difficulty in eating
because of reduced masticatory function.
Summary 143
• There may be temporomandibular joint (TMJ) disorders.
• There may be problems in phonation.
Although the patient may not complain of any symptoms
INCIDENCE OF TOOTH SUBSTANCE LOSS or notice problems, the clinician may suggest treatment
because the TSL is progressing and the dentition requires
There is a paucity of data on the incidence of tooth protection from further tooth loss by restorations. The
substance loss (TSL) in the population, but anecdotal dentist may also suggest treatment because of reduced
evidence suggests that in some countries, such as the UK, function, temporomandibular joint (TMJ) disorders or
it is increasing among all age groups, while in others, such compromised aesthetics.
as the USA, the problems are not so severe, at least within From the above, it is apparent that there will be cases in
the younger age groups. In general, the TSL which affects which the patient is unaware of the problem because of its
the younger age groups tends to be erosive, as a result of slow rate of progression. In general, therefore, except in
overconsumption of carbonated beverages, while in the cases of erosive TSL in young patients, treatment can be
older age groups, TSL is more likely to be multifactorial. planned at a relaxed pace.
The prevelance of tooth wear from different studies in A definition of pathological tooth wear is given in
children is shown in Table 11.1. Box 11.1.
135
Restorative Dentistry
Box 11.1 Pathological tooth wear as defined by Smith Box 11.2 Causes of erosive tooth wear (Watson &
& Knight (1984) Burke 2000)
• Pulp exposure Extrinsic erosion
• Loss of vitality due to tooth wear (caused by acid originating outside the body; generally the
• Exposure of tertiary dentine pH is 2.5 or less)
• Exposure of dentine on buccal or lingual surfaces • Environmental – wine tasters, swimmers, acid fumes
• Notched cervical surfaces (unlikely since the advent of industrial legislation)
• Cupped incisal or occlusal surfaces • Dietary – soft drinks, acidic food
• Wear in one arch more than the other • Medications – vitamin C, mouthwashes
• Inability to make contact between worn incisal or • Lifestyle – sports drinks, ecstasy (drug), frothing
occlusal surfaces in any excursion of the mandible
Intrinsic erosion
• Restorations projecting above the tooth surface
(due to stomach acid reaching the teeth, with a pH of 1;
• Wear producing persistent sensitivity
this acid is typically 100 times stronger than in extrinsic
• Reduction in length of incisor teeth so that the length is
erosion, and therefore much more destructive)
out of proportion to the width
• Gastric reflux:
– Sphincter incompetence: oesophagitis, hiatus hernia,
pregnancy, diet, drugs, neuromuscular disease
– Increased gastric pressure: obesity, pregnancy, ascites
– Increased gastric volume: after meals, gut obstruction,
THE HISTORY spasm
• Vomiting:
In all cases, it is essential that a full history is taken and a – Psychosomatic: stress-induced, bulimia nervosa,
complete examination carried out with the aim of making anorexia nervosa
– Gastrointestinal disorders
a definitive and accurate diagnosis (Box 11.2). Patients – Drug-induced: primary, secondary, xerostomia
should be asked to give details of their concerns and • Regurgitation
symptoms, if any, and for how long the symptoms have • Rumination
been present. A patient complaint of sensitivity to cold and
heat may indicate rapid loss of tooth substance, as
secondary dentine is not being laid down as quickly as the
TSL is occurring. This may suggest that early intervention
is indicated before the pulp becomes irreversibly damaged. tation. In this habit, recently eaten food is forced from the
Chipping of incisal enamel is another factor that patients stomach by strong contractions of the abdominal muscles.
may notice. The rapidity with which this is occurring may The food is chewed again and re-swallowed, often many
also indicate the rapidity of the TSL. Most commonly, the times, thus providing the opportunity for erosion of the
patient’s presenting complaint will be of poor aesthetics teeth. Surprisingly, this strange behaviour is fairly common
relating to shortened teeth, incisal translucency and/or and the habit can last a lifetime.
chipping, or functional problems such as difficulty in Pregnancy may indirectly be associated with TSL, given
chewing. Ascertaining the patient’s reason for attendance the possibility of repeated vomiting as a result of morning
should give an indication of eagerness for treatment and sickness.
what particular factors should be addressed. The history A number of medications may be associated with TSL,
should also give an indication of possible patient including chewable vitamin C, hydrochloric acid for
compliance, given that patients who are unaware of their achlorhydria and some iron-containing preparations. The
dental problems are unlikely to be willing to undergo an use of the drug ecstasy reduces salivary flow. The mixture
extensive course of treatment. In such cases, the problems of dry mouth, vigorous ‘raving’ and rehydration with acidic
should be carefully explained and an appointment made to drinks is linked to erosion.
review the patient’s attitude. Should the patient’s compliance Diets high in fibrous foods and citrus fruits may also
be in any way suspect, minimal treatment only should be predispose to TSL, as may diets which are high in
offered at the outset. carbonated beverages such as cola drinks. Some patients
The patient’s medical history should be taken carefully, ‘swish’ the cola drink around their mouths, which is likely
with special reference to medical conditions associated to increase the overall erosive effect, by increasing the time
with TSL. These include gastric ulceration, hiatus hernia, that the drink is held in the mouth. In cases where diet is
oesophagitis, gastro-oesophageal reflux and, indeed, any suspected as being contributory to TSL, the patient should
medical condition which predisposes to gastric regurgita- be asked to keep a diet diary for a number of days.
tion. The patient should be asked about indigestion and Excessive alcohol consumption may result in vomiting
heartburn, both of which may indicate a tendency for and/or gastritis, both of which could be contributory
gastric reflux. However, the condition may be subclinical, factors to TSL.
in that the patient may be unaware of the occurrence of In the past, the patient’s occupation was considered to
136 gastric reflux. Rumination is often confused with regurgi- be of relevance (e.g. erosion was found to be associated
11 / Treatment of tooth substance loss
Counselling
These patients should be apprised of the cause of their
TSL and how further progress of the condition may be
Fig. 11.3 Patient with considerable tooth substance loss, but little limited. It may well be that their rate of disease progres-
138 interocclusal clearance. sion is slow and they should be told this. For patients in
11 / Treatment of tooth substance loss
(a) (b)
For anterior teeth, the choice of restorative material viable alternatives, in view of the reduced rates of success
depends, to some extent, on the amount of tooth substance of post-retained crowns, when compared with other full-
remaining. A shortened crown will be unlikely to achieve coverage restorations. It should also be stressed that the
the necessary retention for a non-adhesive restorative retention of each individual crown is of importance and
procedure such as a metal ceramic crown cemented with that no additional retention is gained by splinting a series
a ‘traditional’ cement. In such cases, it will be necessary of crowns which, individually, have compromised reten-
either to undertake a crown-lengthening procedure or to tion. The use of adhesive, dentine-bonded crowns in cases
use an adhesive crown, such as a dentine-bonded crown. of TSL appears to be increasing, due to the ease by which
If the latter is used in cases where the tooth is shortened retention may be achieved, the need for only minimal
due to TSL, the completed restoration is also likely to be additional tooth preparation and the good aesthetic result
shorter than is ideal from an aesthetic viewpoint, and the which may be achieved. Further research is required to
patient may elect to undertake crown-lengthening surgery determine the long-term success of these restorations in
to achieve an improvement in aesthetics by improving the such cases.
crown length to width ratio (Fig. 11.8). Finally, for patients whose TSL has a bruxist element, it
It should be stated that the addition of retentive features is essential that this is controlled before treatment, or that
such as grooves may enhance resistance form and protect the patient agrees to wear a night bite-guard or splint
the bond in adhesive techniques. The preparation for following the restorative process (Fig. 11.9). Furthermore,
dentine-bonded crowns should not be extended subgin- such patients should be made aware that their bruxist
givally because of difficulties in isolation at the fit appoint- habit is likely to reduce the longevity of their new restora-
ment, but for non-adhesive crowns, full use of the gingival tions. Patients whose teeth have been affected by TSL at
crevice may be necessary to achieve the optimal retention. an early age should also be made aware that their restora-
It is the considered view of the authors that devitalisation tive cycle has commenced at a much earlier stage than
of the pulp and root canal treatment for reasons of reten- would have occurred if normal physiological mechanisms
tion should not be resorted to unless there are no other had been the cause of their TSL. They should be told that 141
Restorative Dentistry
(a) (b)
(c) (d)
(e) (f)
(g) (h)
Fig. 11.8 Crown-lengthening surgery. Case prior to surgery (a); inverse level incision (b, c); removal of soft tissue (d); 1 mm of bone is
142 removed (e); the flap is repositioned (f) and sutured (g); the final result (h).
11 / Treatment of tooth substance loss
SUMMARY
143
12 The principles of tooth
replacement
‘sh’, rely on contact between the tongue and the surfaces long term, with a removable prosthesis being present
of the hard and soft tissues. during the healing phase. Bridges are ideal for restoring
For a patient, the idea of a fixed prosthesis is usually small spaces within an otherwise complete arch where
more attractive than that of a removable partial denture there are strong and well-supported teeth on one or both
which has to be taken out to be cleaned. However, although ends of the space. If the vertical height of the space has
a patient’s wishes are an important consideration, the been diminished by the over-eruption of an unopposed
clinical decision on the final prosthesis may be driven by tooth, it is sometimes possible to crown it to produce a
dental concerns (Box 12.1). In some cases, where aesthetics more favourable occlusal plane (Fig. 12.1). Alternatively,
is not a consideration and the occlusion is stable, a simple the over-erupted opposing tooth can be intruded by a
option is to leave the space unfilled and monitor the situa- Dahl appliance. This involves the use of a removable or
tion. A prosthesis in this situation will often add compli- cemented appliance to encourage axial tooth movement
cation and interfere with periodontal care and should not (Fig. 12.2). As the numbers of missing teeth increase, the
be contemplated unless there is a strong clinical reason to balance swings in favour of removable partial denture
do so. therapy. Some patients may be best treated by a combi-
nation of bridgework and removable prostheses. Further-
more, the concept of the ‘shortened dental arch’ should
Dental factors
be kept in mind when considering treatment options
The number and position of teeth that are lost will (Fig. 12.3, Box 12.2).
influence the clinical decision. Furthermore, the status of The abutment teeth must have sufficient tooth structure
the abutment teeth on either side of the edentulous space to be able to withstand the extra forces placed on them.
will dictate the type of restoration to be placed. A single
incisor tooth with sound abutment teeth will favour the
provision of a fixed restoration such as an etch-retained
bridge, whilst the loss of four anterior teeth will produce a
large span that may be more suitable for a removable
partial denture. The loss of a single tooth is often best
treated with a fixed prosthesis or implant fixture in the
susceptibility to dental disease such as caries, and expe- functional loads. This is an important visit and it is easy to
rience and attitude to periodontal care, will provide further make mistakes during the impression-taking and design
insights to the complexity of the treatment that should be stages which may influence the final restoration. High-
undertaken. Diet sheets are a useful way of identifying quality casts which reproduce both hard and soft tissues
potential caries or erosive attack of the teeth. History of will determine the accuracy of the design (Fig. 12.4).
smoking will indicate a potential susceptibility to peri-
odontal disease and is contraindicated in advanced
Design
treatment procedures (such as implant placement) due to
poor post-surgical healing. Long-drawn-out procedures or An occlusal record is required and this is made at a
treatment plans may not be possible with patients who separate clinical visit. It will involve a retruded axis regis-
have medical conditions which prevent regular attendance. tration in wax combined with a face bow recording. If a
The majority of patients become keenly interested in fixed number of teeth are missing then wax occlusal rims are
bridgework when the advantages of such treatment for required. The jaw relationship is recorded and the casts
restoring edentulous spaces are explained to them. Those mounted on an articulator before the provisional design of
who lack interest or refuse to accept their role in the control restoration is made.
of dental disease are not suitable candidates for indirect
work. Very nervous patients may also be unsuitable on
Registration of the jaw relationship
grounds of temperament.
Social factors which will influence attendance, such A specific jaw relationship is required for transfer to the
as distance to travel, employment considerations or family articulator. This will be made for a contact relationship of
circumstances, must be considered. Finally, the costs the teeth, which may be either the intercuspal position
involved will have a bearing on treatment options and it (ICP) or retruded contact position (RCP). The ICP is the
is always wise to plan for the least demanding option position of maximum intercuspation of the posterior teeth.
which brings about the most success and which is also It is characterised by simultaneous contact with no
cost-effective. anteroposterior or lateral slide as the mandible closes. A
patient will enter this position spontaneously and it is the
closest relationship of the mandible to the maxilla. The
CLINICAL ASSESSMENT OF THE INDIVIDUAL RCP is a contact relationship of the mandible located up
SPACE TO BE RESTORED to 1–1.5 mm distal to the ICP. There is a forward move-
ment from RCP to ICP with no deviation. If there are
The provision of a fixed or removable partial denture is sufficient teeth present, the casts may be hand articulated
written up in a detailed treatment plan contained within without the need for occlusal rims, but a full registration
the patient’s notes. In simple cases, such a procedure will will be required if there are insufficient teeth for stable
often be the last item of treatment provision. However, positioning of the casts. This latter position will be needed
in more complex cases, where there are multiple plastic if there is no natural tooth-to-tooth contact.
restorations and possible provision of crowns, considera- The registration is made with wax occlusal rims on a
tion of the fixed or removable prosthesis is made at an shellac base for the upper, and a wire strengthener for the
early stage in the treatment. lower. If there are insufficient numbers of missing teeth,
When the previous restorative treatment has been
completed, the initial preparatory work consists of taking
preliminary impressions and a design is drawn up using
these preliminary casts. The vitality, periodontal support
and health of the potential abutments should be assessed.
Radiographic investigation will aid in determining:
• the size and position of the dental pulp
• the gingival and pulpal extent of any caries or restorations
• the condition and level of the alveolar support
• the shape and length of the abutment root(s)
• the periapical status.
The patient’s occlusion should be checked in inter-
cuspal position and in lateral and protrusive excursions,
to assess the clearance that can be achieved during tooth
preparation. An assessment should be made of the occlusal
forces likely to be borne by the prosthesis during function.
148 Marked wear facets are often an indication of heavy para- Fig. 12.4 Mounted study casts duplicating hard and soft tissues.
12 / The principles of tooth replacement
Fig. 12.6 Picture of face bow recording using the Dentatus face
bow.
procedures such as a diagnostic wax-up prior to embarking In preparing teeth for conventional bridge retainers, it
on the bridge procedure (Box 12.4). is often necessary to remove substantial amounts of sound
Photographs can form a valuable record of the preoper- tooth tissue. Whilst an unrestored sound tooth makes the
ative condition. The patient must be given an estimate of best abutment to prepare from a mechanical viewpoint,
the total time involved in treatment as well as the probable extensive cutting of tooth tissue can lead to loss of pulp
length of appointments and the intervals in between. Serial vitality. The amount of tooth tissue to be removed may be
study casts may also be of use in assessing the progress of greater than for individual preparations because mutual
tooth wear and whether the occlusion has stabilised.There parallelism may be required between abutments that are
are many clinical reasons for constructing a bridge, such as out of alignment. In addition, space may be required within
deterioration of the occlusion if a space is left unrestored. the retainer contours for a movable joint. The decision to
Teeth adjacent to the space may drift and cause premature provide a bridge must take these factors into account and
occlusal contacts or loss of contact leading to food packing the operator must be convinced that the risk of pulpal
and the risk of caries and periodontal disease. Loss of necrosis is minimal before proceeding with such treatment.
function is not a serious issue if the gap is small. Although
occlusal stability may initially be lost as a result of extraction Types of bridge
and non-replacement, tooth movement may result in an
Fixed-fixed
occlusal relationship that becomes stable over time and is
functionally acceptable. In cases of doubt, serial study casts In this type of bridge, all joints are either soldered or cast
will allow an assessment to be made as to whether there in one piece, rigidly connecting all the abutment teeth
is occlusal stability. In some circumstances, orthodontic (Fig. 12.7). It requires equal or good retention at either
treatment will be required to realign teeth or to regain lost end of the edentulous span, and it must be possible to
space before embarking on bridgework. In these circum- produce mutual parallelism of all retainers. This type of
stances, the bridge may serve an additional function of bridge is simple to construct and affords rigid splinting. It
maintaining the result of the orthodontic treatment. provides maximum retention and support for long spans
Improvement of appearance is an important reason and gives cross-arch splinting for larger bridges when the
for constructing an anterior bridge. In many cases, a well- periodontal tissues are reduced. It demands heavy tooth
constructed partial denture may prove superior to an preparation with the risk of overtaper when preparations
anterior bridge from an aesthetic viewpoint. However, are not mutually aligned and/or the span is long. Accurate
the greater comfort and stability provided by a bridge may construction and cementation may be difficult in cases
outweigh the previous consideration. Finally, a most with long spans. Significant framework distortion may occur
important indication for a bridge flows from the fact that when firing the porcelain veneer. For this reason it is recom-
all types of restoration may cause damage to the teeth and mended to avoid metal/ceramic bridges over four units in
supporting tissues. A bridge may be superior to a denture length. Catastrophic failures frequently occur when this
because it covers less tissue and consequently has less type of bridge is incorrectly prescribed or poorly executed.
potential for periodontal damage. Replacement of missing
teeth with partial dentures may be a common source of
Fixed-movable
periodontal disease when diet and plaque control are not
adequate. However, there is a biological price to pay with This type of bridge incorporates a stress-redistributing
a conventional fixed prosthesis, and long-term studies of device which allows limited movement at one of the joints
crowned teeth show that in 0.5–10% of cases, pulpal necrosis
and periapical lesions may develop following extensive
crown procedures.
Fig. 12.8 Fixed-movable bridge with major retainer distal to Fig. 12.10 Spring cantilever bridge replacing UR1 with FVC
pontic. retainers at UR5 and UR6. 151
Restorative Dentistry
The spring cantilever bridge provides an aesthetic solu- occurred, it may be possible to correct it orthodontically.
tion to the problem of replacing a missing upper incisor Alternatively, retainers may be constructed that are
when the anterior teeth are spaced. The connecting bar narrower mesiodistally than the original abutment teeth.
should follow a wide curve to provide additional mucosal Overlapping pontic designs can give a pleasing appearance
support and limit adverse leverage. The bar should be oval in some situations. If the span length is excessive for a
in cross-section and taper from the retainer to the pontic. normal-sized pontic, alternative possibilities include ortho-
It is not well suited for patients with steeply vaulted dontic treatment, wider retainers, and alternative designs
palates. Oral hygiene can be maintained by using dental of bridgework such as spring cantilever.
floss to clean beneath the bar. This type of bridge involves
permanent mucosal coverage and should therefore be
Principles of tooth preparation
used with discretion. Its use has fallen out of favour in
recent years with the advent of more predictable implant Optimal tooth preparation involves the triad of biological,
treatment. mechanical and aesthetic principles (Box 12.6). The
strength of a bridge is limited by the strength of its indi-
vidual components. It is dependent on the materials used,
Compound
their dimensions and the method of linkage to each other
A combination of any two or more of the above designs and to the supporting tissues. Regions of potential weak-
may be referred to as compound or complex. As a general ness are solder joints, connectors, and occlusal and incisal
principle, it is best to use several small bridges to replace a surfaces. The requirements of strength for any bridge will
number of missing teeth, rather than replace them all with depend on the amount of masticatory force it has to resist
one large complex or compound bridge. This will simplify over the length of the span. A bridge opposed by a denture
replacement if a single bridge unit fails. has to resist much less occlusal force than one opposed by
natural teeth. Aesthetics becomes increasingly important
towards the front of the mouth. If the patient is prepared
Treatment planning/preparatory work
to show some gold, a more conservative retainer design
Box 12.5 provides a useful checklist after the bridge design may be possible (either conventional partial veneer or
has been completed and prior to commencement of the resin-bonded). Metal ceramic crowns can produce
clinical procedures. excellent appearance, but considerable tooth reduction is
required labially and occlusally in order to accommodate
the metal frame and the porcelain veneer. In situations
Orthodontic considerations
where there is minimal occlusal stress, an all-porcelain
It may often be necessary to correct malpositioned teeth metal-free bridge can provide the best appearance. The
adjacent to an edentulous space. When a tooth is tilted, it failure rate of such bridges has been reduced with modern
is difficult to obtain a common path of insertion with other adhesive materials and techniques. Fibre reinforced
abutments and it may also be difficult to prepare for a composites are also being introduced for metal-free
retentive retainer. Furthermore, if abutments are prepared adhesive bridgework. These may be used with direct
in their tilted position, periodontal problems may occur (chairside) or indirect (laboratory fabricated) approaches.
between abutment and pontic, as plaque removal becomes They are considered to be best in anterior fixed-fixed
difficult when interproximal spaces are inaccessible. restorations where occlusal loading is less and support is
The space available for the pontic is important in the provided at both ends of the span.
anterior region to allow good appearance. If space loss has
152
12 / The principles of tooth replacement
Bridge design
In choosing the design of bridge for a particular space, a
number of decisions have to be made. Even for the
replacement of a single missing tooth there are many
possible variants in bridge design, including the number of
abutments to be employed, the types of retainers to be
used, the design of bridge to be selected and the choice
of luting cement. Meta-analyses of the survival of conven-
tional fixed prostheses show that whilst the survival prob-
ability is good at 5-year recall (4 or 5% failure), the failure
rate increases after 10 years. At 15-year recall, failure rates
are typically 25–30% and the principal mode of failure is
by loosening or recurrent caries. When there is partial loss
of cementation of a bridge, this may go unnoticed by the
patient for some considerable time. This can result in
extensive caries of the failed abutment, which can jeopar-
dise the success of any replacement bridge or lead to loss
of that abutment (Fig. 12.11).
When the abutment in question is a critical or terminal
abutment, a replacement bridge may then become impos-
sible, and hence the choice of bridge design and selection
of retainers are crucial for long-term success. A common
cause of bridge failure is the choice of abutments with Fig. 12.11 Extensive caries revealed following removal of a
crowns that are too small to provide sufficient retention.The complex bridge. The distal retainer required extraction.
clinical crown height should be sufficient to allow adequate
retainer preparation. Any tooth with less than 4 mm crown only occurs in intercuspal position because of canine
height from marginal ridge to gum margin is questionable guidance. The extent of previous restorations, caries or
as an abutment. Slots, grooves, pins and adhesive cements endodontic treatment may have severely weakened the
may be used to increase retention in the case of short crown of a potential abutment. The extent of any caries on
crowns, but their use complicates design and construction. previous restorations must be known before the choice of
The longer the span, the greater the stress on the retainer can be finalised. Failure to do so can result in a
retainers will be and the greater the risk of cementation hasty design change during tooth preparation, which can
failure. Replacement of a missing molar requires more lead to early failure. Whilst minor internal undercuts in a
retentive preparation than for a lower incisor. Replacing an preparation can be obliterated with cement, larger losses
upper first premolar in a patient with group function of tooth tissue are best dealt with by incorporating features
occlusion will make more demands on bridge retention into the tooth preparation to compensate for inadequate
than for a situation where occlusal function on the pontic retention/resistance form (Table 12.1).
Total loss of coronal All cusps undermined/lost As above plus elective endodontics Full veneer
tooth structure Supragingival height <1 mm and post/core for premolars
1.5–2.0 mm circumferential ferrule
153
Restorative Dentistry
Root-treated teeth may require a post placed to aid to full crown retainers. This is because the abutment can
retention of the core. The shape of an abutment crown be depressed in its socket while the retainer is supported
may present retention problems when dealing with conical by the remainder of the bridge. This can cause fracture of
or short teeth. Retention of this type of retainer depends the relatively weak cement seal. However, inlay retainers
on placing grooves or slots in axial surfaces in addition to have been shown to be more successful in resin-bonded
obtaining near-parallelism of opposing surfaces.Whilst the bridgework. This is because of the better mechanical
standard texts recommend taper angles of 2–6°, this is not properties and adhesion of the luting resin cement to
routinely possible in clinical practice. A taper angle of 3° retainer and tooth. The MOD inlay with covered cusps
equates to a convergence angle of 6°. Mean convergence (also called MOD onlay) is the minimum design of major
angles of bridge preparations from commercial laboratories retainer that should normally be considered for a posterior
range from 15° to 30° and hence a taper angle of 8° is bridge. It has been argued that both approximal surfaces
more realistic. Long, narrow tooth preparations can have should always be covered for major retainers as subsequent
greater taper than short, wide preparations without sacri- caries of an uninvolved surface could endanger the bridge.
ficing resistance. The latter require near-parallel walls if A more modern biological approach would be to secure
adequate resistance form is to be obtained. Special atten- adequate retention and resistance features by appropriate
tion should be given to any tooth where the extent of bridge design and material selection. Caries rate must be
caries of previous restoration has jeopardised pulp vitality. low and caries control excellent before any bridge is provided
Investigations of crowned teeth reveal a twofold increase in for a patient. Buccal and lingual extensions of an onlay
pulpal necrosis where the tooth has a pin-retained core. preparation will aid the retention of this type of retainer
When there is doubt about continued pulp viability, it may even if only one proximal surface is involved (Fig. 12.12).
be wise to undertake elective endodontic treatment in
advance of proceeding to abutment tooth preparation. Partial veneer crowns
Partial veneer crowns are preferred to full veneer crowns
Choice of retainers where adequate retention and resistance form can be
obtained, even when they are used as retainers for conven-
Factors which affect the choice of retainer include:
tional bridge preparations. The advantages and disadvan-
• the retention required tages of partial veneer crowns as compared with more
• bridge design extensive full veneers are as follows:
• amount of sound coronal tissue available
Advantages
• strength of dentine after preparation
• Conservative
• extent of existing restorations
• Minimal gingival involvement
• occlusal protection required
• Vitality testing possible
• amount of metal display tolerable.
• Fit is readily assessed
Supragingival margins are preferred wherever possible • Cementation is easy
because they simplify bridge preparation, impression-taking • Margins are accessible
and cementation, in addition to helping maintain peri- • Versatile insertion path.
odontal health. Retainer margins may have to be placed
subgingivally in order to cover existing restorations, gain
adequate retention or hide metal display anteriorly. In such
situations, the biological width must always be maintained.
Tooth preparations should only ever be placed into the
gingival sulcus and not encroach on the epithelial attach-
ment. Inlays, partial and complete veneer crowns, and
telescopic crowns, are the alternative retainers available to
bridgework. Pins, posts and adhesive cements will all add
to the retention.
Intracoronal inlays
In the case of the conventional bridge design, the use of
intracoronal inlays without cuspal coverage is restricted to
the minor retainer of a fixed-movable bridge. Studies have
shown that when inlays are used without cuspal coverage Fig. 12.12 Mesial half-crown preparation for long-span mandibular
as the retainers in a conventional fixed-fixed bridge, the resin-bonded bridge. Note buccal and lingual slots and presence of
154 failure rate is increased greater than 10-fold in comparison varnish to facilitate removal of excess resin after bonding.
12 / The principles of tooth replacement
Clinical decisions
Many decisions about tooth preparation design can be
Fig. 12.14 Posterior metal ceramic bridge retainers at UL3 and
made from trial preparations on articulated diagnostic
UL5 showing partial and full porcelain cover.
casts. The best location for partial veneer margins and
Metal Porcelain
Short teeth Aesthetics is critical
Large pulp Large teeth
Opposing enamel/metal Heavily restored teeth
occlusals
Parafunction Opposing porcelain occlusal
Group function occlusion Steep anterior guidance
Simple adjustment Difficult adjustment
Average technical support Excellent technical support
Bridge design
Although fixed-fixed, fixed-movable, cantilever and spring
cantilever designs have all been used, the preferred designs
for resin-bonded bridgework are cantilever and fixed-
movable. Debonding of one retainer of a fixed-fixed design
is relatively common because of differences in retainer
coverage and retention combined with variations in peri-
odontal support and occlusal loading. Unilateral debond-
Hybrid bridges
These are ideal where a heavily restored or previously
crowned tooth exists at one end of an edentulous span and
there is a sound abutment tooth at the other end. Resin-
bonded retainers may be used in combination with
conventional bridge retainers when a fixed-movable
connector is employed. If a fixed-fixed design was used,
cementation would be complicated by the need for mixing
and using different cements simultaneously. In addition, if
Fig. 12.21 Hybrid fixed-movable bridge with resin-bonded onlay
there is cementation failure of the resin-bonded retainer, major retainer on molar.
caries of the abutment is invited because the bridge is still
retained by the more retentive conventional unit. For
hybrid bridges the resin-bonded retainer should be made casting to the telescopic crown. If the resin-bonded unit
as the major retainer (Fig. 12.21). Debonding will there- becomes uncemented, it is an easy matter to remove the
fore not require replacement of the original retainer. It is bridge, and if the overcasting becomes uncemented,
also easier to create room for a removable joint within the the telescopic crown protects the conventional unit from
confines of a conventional retainer. Placing the joint extra- caries.
coronally in the pontic section is not recommended as the
lever arm created invites failure. Alternatively, a telescopic
Resin-bonded versus conventional bridges
or sleeve crown may be permanently cemented to the
carious or restored tooth and a fixed-fixed design employed Resin-bonded bridges should always be considered first
whereby a chemically active resin cement is used to retain and rejected as a possible option before a conventional
the resin-bonded unit and a temporary conventional bridge design is considered.This is because they are highly
cement is used to cement the conventional crown over- conservative, involving minimal tooth preparation. No 159
Restorative Dentistry
anaesthesia is required unless there is dentine involve- is weakened by the perforations and the fact that the
ment. Modern dentine-bonding agents have expanded the composite lute is exposed to the oral environment (Fig.
indications and versatility of resin-bonded bridges. Whilst 12.23). However, Rochette bridges still have a role as
the tooth preparation is quick, it is also exacting because immediate or interim replacements or as part of a complex
of the ‘white on white’ effect of confining preparations to treatment plan. Where the prognosis for a bridge is in
enamel during development of retention and resistance doubt because of questionable support, a Rochette bridge
form. There is no risk of soft tissue trauma because of the may be constructed as a diagnostic measure with no tooth
supragingival finish lines for these impressions and this preparation. Once it has been established that the
simplifies preparation. There is usually no need for any periodontal support is sufficient, then it is a relatively easy
provisional restoration. Occlusal clearance can be main- matter to remove this type of bridge by simply drilling out
tained by spot-etching and placement of a small amount of the resin composite from the retention holes and tapping
composite on the opposing tooth to act as a centric stop the bridge off.
(Fig. 12.22). Other types of mechanical retention such as mesh and
Where dentine is involved at the base of a groove or particle roughened retention have fallen out of favour
occlusal offset, this can be covered temporarily with a because they add bulk to the casting and are not as
polycarboxylate cement. An air scaler is useful to remove retentive as alternative designs. The most popular type of
the cement without further damage to the preparation at micromechanical retention involves grit-blasting with
the time of cementation. Whilst modern designs of resin- 50 μm aluminium oxide, followed by silicon oxide coating
bonded bridge usually incorporate retention and resistance (the Silicoater technique) or use of a chemically active
form together with a precise path of seating, it is frequently resin cement. In this situation, retention is both mechanical
not possible to assess the need for occlusal adjustment and chemical (microchemical). Electrolytic and chemical
until the bridge has been seated. Cementation or ‘bond- etching techniques have fallen out of favour because the
ing’ is more technique-sensitive than for a conventional laboratory technique was highly sensitive to error and
bridge and requires considerably more time; hence the special apparatus was required. In addition, beryllium-
time that is gained during tooth preparation and provisional containing nickel chrome alloys, which were most amenable
prosthesis is offset during cementation. Resin-bonded bridges to etching, are now not considered safe for routine labora-
must not be seen as a quick-fix solution. tory use. Chemically active resin composite cements form
bonds to the oxidised surfaces of non-precious alloys. Two
effective materials are Panavia 21 (Kuraray) and Metabond
Metal/resin retention techniques
(Parkell). The former contains an active phosphate ester
Reliable retention of resin cements to prepared enamel and the latter 4-META as the active chemical agents.
surfaces may be obtained with the acid-etch technique. Contamination of the grit-blasted non-precious alloy
This bond is micromechanical in nature. The retention surface must be avoided as this seriously impairs the bond.
techniques for resin to metal are based on mechanical, Even momentary contamination with saliva will reduce
micromechanical or microchemical techniques with or the bond by 50% and contaminated surfaces are very diffi-
without the use of chemically active resin cements. The cult to clean effectively. This can involve 30-minute ultra-
Rochette design has limited retention and the framework sonic treatment in a suitable surfactant solution at high
temperature. Chairside grit-blasting units allow metal
surface treatment between try-in and cementation. In the a chemically active resin. Type 3 or type 4 gold alloys
case of precious metals, effective adhesion of resin to metal (containing more than 8% copper) can be heat-treated for
may be obtained either by tin plating (Fig. 12.24) or by 4 minutes at 400°C after try-in and grit-blasting to make
heat treatment of hard gold alloys which contain more them amenable to bonding with a chemically-active resin
than 8% copper (Fig. 12.25). cement.
An alternative technique for chemical bonding is based
on the adhesion of a resin to silane-bonding agents. The Guidelines for resin-bonded bridges (assuming
Silicoater technique allows a very thin glass-like layer to be metal framework used)
built up on the roughened metal fit surface of the bridge.
Abutment tooth preparations
This surface has to be protected with an opaque layer or
a layer of resin if the bridge is not to be cemented within Appropriate preparation improves the retention of resin-
30 minutes of treatment. This has limited the widespread bonded bridges by increasing the available area of enamel
application of this technique. for bonding and by reducing functional stresses on the
Non-precious alloys (Ni/Cr or Co/Cr) are preferred for resin composite lute. Preparation also provides increased
resin-bonded bridge frameworks because they are more occlusal clearance and creates a positive path of insertion
rigid in thin section. Their modulus of elasticity is twice and seat for the restoration during try-in and bonding.
that of a type 4 gold. In addition, they are more amenable The removal of the outer enamel surface layer, which is
to bonding with chemically active resins and simply require frequently aprismatic and rich in fluoride, allows for more
grit-blasting of the surface after try-in. Precious metal predictable etching. By removing axial undercuts and
alloys for metal ceramic frameworks (Au/Pd) are best tin- developing guide plane retention, the effective preparation
plated or silicoated after try-in and then cemented with length is increased.
The aim of tooth preparation should be to cover the
maximum enamel area consistent with (i) aesthetic
considerations, (ii) occlusal constraints, and (iii) the need
to fit a rubber dam. A precise path of insertion and seating
should be developed by the preparation for the metal
framework. A retentive framework design limits the
stresses placed on the cement lute and dramatically
increases the success rate. Preparation features and
sufficient alloy thickness should be allowed to reduce
stresses on the bonded joint.
Anterior preparations
• Reduce palatal enamel to allow 0.5 mm interocclusal
clearance in all functional mandibular excursions. Less
reduction is required/indicated for mandibular teeth.
Fig. 12.24 Chairside tin-plating of fit surface of full veneer gold Allow 1 mm clearance for regions of heavy occlusal load.
crown. • Extend cervically to 1 mm from gum margin.
• Extend within 1–2 mm of incisal edge depending on
functional and aesthetic considerations.
• Extend proximally (adjacent to the edentulous space)
as far as appearance permits.
• Extend proximally (opposite to the edentulous space)
to within 1 mm of the contact area.
• Provide a cingulum rest to aid resistance form.
• Use proximal grooves and/or cingulum pinholes as sub-
stitutes for labial wrap circumferential retention. Stabilise
the framework on each abutment in the plane perpen-
dicular to the path of insertion with these features.
Posterior preparations
• Replace any small proximal amalgam restorations with
Fig. 12.25 Fit surface of heat-treated gold onlay for upper molar composite and/or glass ionomer cement or use a
with luting resin composite. dentine adhesive. 161
Restorative Dentistry
• Reduce proximal and lingual/palatal axial surfaces to fixed-fixed resin-bonded bridges difficult and less successful.
provide a >180° ‘wrap-around’ effect. When crown Single retainer simple cantilever designs are the first choice
height is limited, a 360° sleeve coverage can be used wherever possible; if circumstances do not permit then
whilst maintaining occlusal stability. Obtain a minimum fixed-movable or hybrid designs are the next best.
of >3 mm guide plane retention axially. There is a higher failure rate for perforated retainers,
• If necessary, accept knife-edge finish proximally and/or multiple abutments and/or pontics, mobile teeth and young
lingually to avoid dentine exposure. patients. Common reasons for failure include:
• Use occlusal onlay coverage to supplement bonding
area on short teeth.
• poor case selection
• Make occlusal rest seat preparations.
• inadequate bridge design
• Use shallow proximal grooves and occlusal inlays to
• inadequate tooth preparation
assist retention and compensate for lack of circum-
• faulty bonding procedure
ferential retention.
• occlusal factors.
• Join intracoronal retention features to the extracoronal Whilst some authors advocate the re-cementation of
part of the preparation with offsets and isthmuses to a debonded resin-bonded bridge, such a procedure
maximise retention and resistance (Fig. 12.26). frequently leads to repeated failure.The risk increases with
each rebond. Frequent debonding and replacement of
restorations is clinically frustrating and economically
Try-in and cementation or bonding
unsound. Rebonding a resin-bonded bridge involves much
• Try-in the bridge to check for fit, contour and path of more time and effort than merely re-cementing a loose
insertion. crown or conventional fixed prosthesis. It is necessary to
• Assess occlusion at this stage if the bridge is sufficiently remove contaminants from both adherent (bridge fit surface
stable. and tooth) surfaces and to re-prepare them for rebonding.
• Place a rubber dam, allowing slack in pontic region for This procedure inevitably reduces the precision of fit and
passive seating of the bridge. increases the luting resin film thickness. Indications for
• Clean the prepared teeth with a pumice/water slurry, rebonding are given in Box 12.9.
rinse and dry. The main cause of debonding must be remedied, provided
• Protect adjacent teeth with matrix strips and acid-etch this does not compromise restoration design.
enamel, rinse and dry.
• Check for characteristic frosted appearance of correctly
REMOVABLE PROSTHESES (REMOVABLE PARTIAL
etched enamel.
DENTURES)
• Apply enamel-dentine (ED) primer to exposed enamel
and dentine surfaces for 60 seconds.
If the decision has been made to undertake a removable
• Evaporate solvent with air.
partial denture (RPD) then a provisional design is com-
• Apply mixed Panavia 21 to retainer fit surfaces.
pleted at the initial treatment planning stage on the
• Seat bridge promptly and remove gross excess with a
articulated casts before undertaking any other restorative
brush or suitable instrument.
treatment.This must be drawn up on a design sheet.Whilst
• Maintain seating pressure. Apply barrier agent
undertaking a design, the following decisions are made
(Oxyguard 2) to the bridge retainer margins after
when assessing whether mouth preparation is required:
removal of excess cement.
• Remove excess cement after set from margins with • Rest seat preparation. This is undertaken to provide both
suitable hand and/or rotary instruments. sufficient space and a horizontal surface for any support
• Remove rubber dam. Check and adjust occlusion. component of a cast metal partial denture. It also aims
• Final finishing of resin/metal margins (using water-cooled to prevent any interference with the occlusion.
burs) is best delayed until 1 week after cementation.
(a) (b)
(c) (d)
Surveying
Fig. 12.28 Design sheet correctly and neatly drawn up.
The initial step in producing any design is a survey of the
casts; a dental surveyor is used for this purpose. This
instrument is used to determine the relative parallelism of
two or more surfaces of the teeth or other parts of the cast
Identify
of a dental arch (Fig. 12.29). Several tools are used with
the surveyor, including an analysing rod, undercut gauges, When examining the casts, movement of the RPD away
a graphite marker and wax/plaster trimmer. It is the from the cast is identified. Any denture will have a path
clinician’s responsibility to survey the casts and use of displacement away from the cast/mouth. It is possible to
this information to design the denture. The surveyor is introduce a path of insertion and removal which is different
used to identify, mark, measure and eliminate undercuts on from the path of displacement (Fig. 12.30). Usually the
the teeth. two are coincident and the clinician will rely on clasps and
guide surfaces for retention of the RPD. However, a path
of insertion and removal different from the path of
displacement will lead to a more retentive denture.
In this identification process, guide surfaces are sought.
They consist of two or more parallel surfaces on the abut-
ment teeth which are used to define the path of insertion.
They also help to aid in stabilising the denture. These
surfaces can be either natural or artificially prepared. This
latter procedure involves either altering the shape of the
tooth with a dental bur or the use of a restoration, which
may range from the simple addition of composite material
to the use of a cast restoration. Retentive surfaces receive
the same identification process. Undercuts around the
teeth are examined and the depth measured. If a clasp is
to be placed, the last third (the retentive part) must rest in
the undercut. This is the elastic element of the clasp which
sits within the undercut. It is the elastic recoil of the clasp
164 Fig. 12.27 Guide surface incorporated into crown. that needs to be overcome as the denture is removed. A
12 / The principles of tooth replacement
Path of displacement
(a)
Fig. 12.31 The cast is tilted with the heels down to take
(b)
advantage of the labial undercut.
Fig. 12.29 (a) Dental surveyor. (b) Surveying tools used (clockwise
from bottom left): analysing rod, undercut gauges, graphite
marker, wax trimmer.
of bony undercuts, prominences or inclined teeth, which
can be avoided by the use of an anterior or posterior tilt.
cast cobalt chrome (Co/Cr) clasp requires a 0.25 mm
undercut and a wrought clasp requires a 0.5 mm undercut
Mark
to be effective.
If the undercut were 0.75 mm or greater, it would cause Once the cast has been thoroughly examined and the areas
permanent deformation of the clasp. An inverted depth of interest or concern identified, it is necessary to mark on
gauge is used to measure such undercuts on the tooth, and the survey lines with the black graphite marker. An alter-
if required the use of a bur or composite material will native colour, such as red, is used to mark any tilting that
either reduce or create potential undercuts. If natural is needed.
surfaces are favourable then tilting of the cast will allow
the RPD to utilise them. This additional surveying is
Measure
carried out with both anterior and posterior tilts. This
is sometimes referred to as ‘heels down’ or ‘heels up’ Any undercuts that are present are then measured with
(Fig. 12.31). This will result in two survey lines, which the undercut gauge (0.25–0.75 mm), which will enable
may help with clasp position, especially in cases with diffi- decisions to be taken on the type of clasp material
cult tooth angulations. Good aesthetics may be important, (wrought stainless steel vs. cast Co/Cr) and its subsequent
especially at the front of the mouth, and the insertion of design (gingival/occlusal approaching). A decision is made
the denture may lead to unsightly gaps between it and the as to the best orientation of the cast for the final survey,
natural teeth. If these occur, they should be eliminated. which gives the best path of insertion together with
Other problems that may be identified include the presence optimal retention. 165
Restorative Dentistry
Eliminate
The clinician can then prepare to eliminate the problems
and assess the need for mouth preparation. Undercuts can
be blocked out using plaster of Paris, which is done on the
master cast. Saddle
The information from the surveyor needs to be
recorded to enable the survey to be interpreted correctly
in the laboratory. The best method for achieving this is
by the process of tripoding, which involves the placement
of three marks on the palatal surface of the cast by the
graphite marker, with the vertical arm of the surveyor
locked at a fixed height (Fig. 12.32).
Design stages
After surveying the cast, the design is drawn up and this
Support Retention
can conveniently be seen as comprising six stages: saddles,
support, retention, reciprocation and bracing, connection
and finally indirect retention (Fig. 12.33).
Saddles
Saddles rest on and cover the alveolar ridge and include
the artificial teeth and gum work. It is this component
of the denture that carries the replacement teeth (Fig.
12.34).
When reviewing the design of the saddle area, the Reciprocation and Connection
bracing
extension of the base is considered and should follow
complete denture principles. It should extend to the depth
of the functional sulcus, unless there are aesthetic consid-
erations such as at the front of the mouth, posteriorly onto
the buccal shelf and halfway up the retromolar pad. The
positioning of the teeth may dictate the saddle position.
Where a tooth is missing, it does not necessarily mean that
a replacement is required, especially when replacing
posterior teeth at the end of the arch. The saddle material
Indirect retention
Support
Support is the resistance to vertical force (i.e. masticatory
forces) directed towards the teeth and mucosa. The partial
denture should dissipate these forces and resist downward
pressure. Resistance to masticatory forces is provided by
either the mucosa or the teeth, or by a combination of the
two. The way in which this resistance is provided deter-
mines the classification of the support (Fig. 12.35b).
Quality of the support. The type of support available
may vary and assessment of its quality is made during
design procedures. Tooth support will be dependent upon
the root area of the abutment teeth, their periodontal
status, conservation status and whether they are able to
withstand occlusal forces. The root area of the abutment
teeth will vary and both molars and canines are the best
suited for this purpose as they have the greatest root
Fig. 12.34 Two unbounded saddles are shown on this wax trial
surface area. The saddles will also influence this support.
denture saddle.
Large saddle areas (three to four teeth) will exert a large
Upper Upper
Lower Lower
(a)
Mixture of
Class III teeth and
Class I Class II mucosa
(b)
Fig. 12.35 (a) Diagram of Kennedy classification. Note that the Kennedy IV has no modifications. (b) Support classification. 167
Restorative Dentistry
force on the adjacent teeth. If large masticatory forces • Point contact between adjacent standing and artificial
from opposing natural teeth are expected, this will increase teeth – intact upper dental arch with contact points
the loading on the saddle areas and therefore onto the which are buccally placed. Point contacts between
supporting elements. natural and artificial teeth are distributed mesiodistally
Mucosal-borne dentures may work well in upper arches, along the arch.
especially if the palatal area is used for support. An area of • Wide embrasures between contiguous standing and
approximately 5 cm2 in the centre of the palate does not artificial teeth.
resorb and it is this which assists in the retention and • ‘Free occlusion’ – a free occlusion with no tendency
stability of upper dentures. Lower acrylic dentures are for the upper and lower cusps to interlock or hinder
often provided but they can cause problems by ‘sinking’ movement.
into the tissues under occlusal loading. This will lead to • Uncovered gingivae – no contact with the gingival
gum stripping and other periodontal problems. Therefore tissue. Palatally the acrylic should be at least 3 mm from
lower mucosal-borne dentures should be avoided unless the gingival margins.
they are seen as transitional in nature (i.e. ready for future • Contact of the denture with the distal surface of the last
immediate additions). standing tooth – distal stabilisers contact posterior teeth
The ‘Every’ type acrylic partial denture is a special and maintain point contact by preventing drifting.
design which attempts to minimise periodontal damage • Maximum retention following the principles used in
and maximise retention (Fig. 12.36). There are six prin- full denture construction – the denture base covers as
ciples involved in its construction: large an area as possible; the fit of the denture is accu-
rate and polished surfaces should be shaped to assist
muscular forces.
Mesial rest
Saddle
(a) (b)
Fig. 12.37a A mesial rest prepared in the tooth with guide Fig. 12.37b Diagram of mesial rest.
surface.
a difficult clinical situation with its characteristic mixture decision. Where possible, a purely mucosal-borne lower
of tooth and mucosa support. Near to the abutment tooth denture in acrylic should be avoided due to the lack of
there is a predominance of tooth support, but further away support available. However, if the teeth have poor peri-
there is more mucosal support (Fig. 12.38). This differen- odontal support then an acrylic denture is provided which
tial support is the problem during loading of the saddle is transitional in nature. Where there are teeth present
area. The upper free end saddle is often easier to treat, as which have a poor prognosis and will require eventual
support is gained from the palate. Generally it is the lower extractions, it is easier to make additions to an all-acrylic
free end saddle that presents the greatest difficulty due to denture than to a metallic one. After examination of the
the reduced anatomical area. free end saddle problem, a diagnosis of the situation is
made and a treatment plan is drawn up to resolve it.
Clinical procedure. A good history of the presenting Initially a preliminary impression in alginate is obtained
problem is taken and the saddle area is assessed during the and this should record the abutment teeth together with
clinical examination. A past history is also taken to see detail of the free end saddle area. Support of the alginate
what previous treatment has been carried out and whether impression is assisted by the use of impression compound
it was successful. Both the periodontal and conservative in the edentulous areas of the tray. Following pouring of
status of the abutment teeth will also influence the clinical the casts, if it is not possible to hand articulate them, an
assessment of the occlusion is required and the patient is
brought back for a preliminary registration.
Occlusal bond
Design considerations
A simple rigid design. A well-designed but rigid Co/Cr
framework is a simple method of treatment. Modifications
may be indicated if the abutment tooth does not possess
an ideal crown shape with suitable undercuts. The tooth
may be modified using composite or guide surfaces created
by grinding with a diamond drill. In the case of heavily
restored teeth, crowning may be indicated. Where the
abutment tooth has poor bone support, the design should
spread the loading away to other adjacent teeth. In order
to dissipate the loading, clasping of the tooth is made with
wrought clasps as distinct to cast clasps. In theory, the
more elastic wrought material will act as a shock-absorber,
reducing loading on the tooth.
At this end the Mixture of tooth At this end of the
tooth absorps saddle force is Modifications. Where there is a free end saddle present,
most of occusal and mucosa transmitted to
bond the mucosa conventional designs should incorporate a mesial place-
ment of the rest. This will reduce anterior posterior forces
Fig. 12.38 Diagram showing differential support. acting on the tooth. As mentioned previously, potentially 169
Restorative Dentistry
damaging lateral forces on the tooth can be reduced by The Co/Cr casting over the free end saddle may either
the use of more flexible wrought clasps and gingivally contact or sit 1–2 mm above the ridge. The latter is
approaching clasps. preferable as it allows relining at a later date. Generally,
the saddle area is a mesh design which allows the acrylic
Use of the altered cast technique. This technique is a selective to be processed underneath. To help with seating, a ‘foot’
impression technique, which imparts a functional load to (small part of Co/Cr which contacts the posterior region)
the denture. A Co/Cr denture constructed for a free end is incorporated into the casting. This acts as a valuable
saddle will need the differential support offered by the abut- reference point when the fit of the framework is checked,
ment tooth which is relatively rigid in its socket, supported by both on the cast and in the mouth. Any lack of contact
the periodontal ligament and the more displaceable denture- may be eliminated by the altered cast technique. There is
bearing mucosa. This impression technique takes into debate on whether this technique is useful but it does
account the differential support provided by both the oral provide an improved impression of the saddle area.
mucosa and the teeth.The treatment follows the use of both
RPI system. Studies on the differential loading of free end
preliminary and master impressions. The Co/Cr casting is
saddles suggested that the mesial placement of occlusal
constructed ready for trial fitting in the mouth (Fig. 12.39).
rests and the use of wrought clasping on the abutment
A close-fitting acrylic special tray is constructed on the
tooth led to more favourable distribution of loading. This
free end saddle of the casting. An impression is taken of
concept is further modified in the RPI system (R = rest;
the free end saddle using either zinc oxide/eugenol impres-
P = distal plate; I = gingivally approaching I-bar). The
sion paste or a medium-viscosity silicone.When the frame-
mesial rest contacts the mesiolingual surface of the abut-
work is placed in the mouth, the impression is taken with
ment tooth and, with the distal plate, reciprocates the
loading on the support elements of the framework only.
action of the retentive I-bar clasp. The abutment tooth is
No finger pressure is applied on the saddle area as this
held in a mesial–distal direction (Fig. 12.40).
would lead to over-displacement of the mucosa. Border
Under functional load the denture will tend to rotate
moulding is carried out as the impression material is
around the mesial rest. Both the plate and I-bar will move
setting. In the laboratory, the free end saddle areas on
downwards and forwards and disengage from the tooth.
the master cast are sectioned and removed. The denture
This will limit the stresses placed on the tooth during
is positioned on the cast and the new saddle areas are
function. Although often well understood theoretically, the
poured. The resulting cast represents the free end saddle
RPI is not always drawn on designs correctly.
areas under conditions which attempt to mimic functional
load. The original technique used functional waxes and Balance of forces. This can be considered as a further refine-
was described as the Applegate technique.The altered cast ment of the RPI system. It consists of a mesial rest and guide
technique improves the distribution of loading on the free surface with a lingual clasp arm extending into the distal
end saddle and the denture is more stable. However, the undercut from the rest. The aim is to ensure that the loads
technique requires good cooperation with the laboratory during function are directed vertically along the long axis of
and may lead to disruption of the occlusion, especially if it the tooth in order to avoid torque and leverage (Fig. 12.41).
is undertaken as a rebasing of the finished denture. This The tooth is held in a similar fashion (i.e. mesial–distal)
can lead to considerable adjustment at the chairside. to the RPI system, but both a mesial rest and guide surface
are prepared in the tooth. The guide surface may be
Fig. 12.39 The use of the altered cast technique – a special tray is
170 made over the free end saddle area. Fig. 12.40 The RPI system.
12 / The principles of tooth replacement
Retention
Retention of a RPD is achieved by the following means:
• mechanical – clasps engaging undercuts on tooth
Fig. 12.41 Clinical use of the balance of force clasp. • neuromuscular – muscles acting on the polished surfaces
• physical forces – arising from maximal coverage of mucosa
• other means – guide surfaces, precision attachments.
unsightly and will often require preparation of the natural
tooth. This will not be a problem if the treatment plan Clasping of the tooth by thin flexible metal remains
involves the placement of a full veneer crown as the mesial the conventional method of achieving retention. A clasp
guide surface can be designed into the crown. The clasp is is a metal arm, which retains or stabilises a denture by
designed so that the retentive tip of the clasp arm is contacting a tooth. It can be described as either occlusally
positioned on the interproximal surface of the abutment approaching or gingivally approaching (Fig. 12.42).
tooth adjacent to the edentulous saddle. The material, length and cross-sectional shape influence
Retention is achieved mesiodistally as opposed to the flexibility of a clasp. The metal clasps may be either
buccolingually. During function there is similar rotational cast Co/Cr or wrought stainles steel, with the latter having
movement to the RPI system and the clasp will disengage. greater flexibility. Typically occlusally approaching cast
In the UK and the USA, dentures using the balance of force Co/Cr clasp needs to be 15 mm long in order to enter into
system are constructed under licence (Equipoise designs). an undercut of 0.25 mm. This is feasible on a molar tooth
Use of stress breakers. These designs attempt to provide some but would not be possible on a premolar tooth. A wrought
degree of flexibility between the clasp unit and the free end clasp can enter the 0.25 mm undercut with a length of
saddle. They can have either a movable joint or a flexible 8 mm and still retain its flexibility. Alternatively, the cast
connection between the direct retainer and the saddle. clasp can maintain a length of 15 mm if it is designed as a
Precision attachments may be used to provide the movable gingivally approaching clasp.
joint. An example of the flexible design is where the Co/Cr An additional feature of the gingivally approaching
casting is split to enable the differential loading between clasp is that it has a trip action on removal that assists with
the saddle and tooth-supported elements. Although such retention. Finally, if the cross-sectional shape of the clasp
designs can be useful, they can be complicated and involve is changed from a round section to a half-round one then
excessive coverage of teeth leading to periodontal problems. it is more resistant to movement in the vertical plane and
will maintain its position relative to the undercut. These
Design of saddle and occlusal table. The design of a are the physical properties of the clasp arm but there are
free end saddle should also follow traditional guidelines other factors which influence the choice.
for denture construction. Such measures should include
maximal extension of the saddle (halfway up the
retromolar pad, extension into the buccal shelf). This will
reduce the load per unit area being placed on the saddles
during function. Narrow posterior teeth will reduce the
degree of lateral force applied by the musculature during
function. Omitting the most distal tooth will reduce the
amount of loading on the abutment tooth by reducing
leverage. The use of narrow teeth will assist in tooth
position and improve the occlusal loading by allowing the
patient to penetrate food more effectively without
increasing the load to the saddle area.
Gingivally approaching Occlusally approaching
Relining of free end saddle. This can prove to be a
frustrating clinical experience. If a saddle is not seating Fig. 12.42 Occlusally and gingivally approaching clasps. 171
Restorative Dentistry
The depth of undercut on the tooth has a direct influence orthodontically during placement and removal, eventually
on the retentive force of the clasp but its position is also leading to non-function of the clasp arm. A reciprocating
important. Typically an occlusally approaching clasp is arm is used to prevent this lateral movement during
placed on molar teeth, and gingivally approaching clasps denture displacement (Fig. 12.44).
are placed on the premolar being influenced by both flexi- The reciprocating element is rigid and therefore forces
bility and aesthetics. There are two designs of occlusally the retentive element to flex as it moves out of the under-
approaching clasp: the three-arm clasp and the ring clasp. cut over the bulbosity of the tooth. This leads to effective
The use of either design depends on the relative position use of the clasp forces on the tooth. Reciprocating elements
of the undercut on the tooth. For instance, a mesial lingual may be contained within the arm of the clasp, as in a
undercut may be best clasped using a ring clasp, whilst a ring clasp, or in an extra arm which is positioned on the
distal lingual undercut may require a three-arm clasp. opposite side of the clasp arm on the tooth. Other recipro-
Extra forces on insertion and removal will be placed on cating elements may be the minor connectors, occlusal
a tooth when it is clasped. Teeth which have reduced rests or guide surfaces which are designed to keep the rest
periodontal attachment may require a more flexible clasp in its correct position and prevent tooth escape when the
such as wrought stainless steel. clasp is activated during displacement.
The sulcus shape will influence decisions on the choice Bracing provides resistance of the whole partial denture
of clasp design. A gingivally approaching clasp may inter- to forces to which it may be subjected during mastication.
fere with bony prominences, prominent frenal attachments These forces attempt to dislodge the denture in both
and shallow sulci. Taking it away from the tissue undercut anteroposterior and lateral directions. The lateral forces
may make it more noticeable to the buccal tissues. may inflict damage on the periodontal and alveolar tissues.
The length of the clasp may be reduced if only premolar Bracing elements may include rests, reciprocating elements
teeth are available for clasping. In order to maintain a and clasps, or other parts of the denture including the
flexible clasp for the appropriate undercut on the premolar saddles (Fig. 12.45).
tooth either a short, occlusally approaching wrought clasp
or a longer, cast Co/Cr gingivally approaching clasp may
Connection
be selected.
Finally, aesthetics will dictate the positioning of the clasps. The saddles, clasps and reciprocating elements need to be
Metal is unsightly and an occlusally approaching clasp connected in order to function as a complete unit. Minor
anterior to the premolar teeth should be avoided where connectors include parts of the Co/Cr framework which
possible; the gingivally approaching clasp is to be preferred. hold these local elements together, while major connectors
However, there are special tooth-coloured porcelain clasps connect the main saddles of the denture.
which can overcome this problem (Fig. 12.43) In the upper metal partial denture, these will cross the
palate and there are many variations on the design. The
main consideration is that all the parts are connected
Reciprocation and bracing
together. The simplest connector design is a full metal
When a tooth is clasped, the arm exerts a lateral force onto plate that covers the palate (Fig. 12.46). This has the
the tooth during insertion and removal of the RPD. If this advantage of rigidity and ease of design; however, the full
lateral force is not resisted, the tooth will be moved coverage may not be comfortable for every patient and
172 Fig. 12.43 Tooth-coloured clasps. Fig. 12.44 The buccal clasp is reciprocated by the palatal arm.
12 / The principles of tooth replacement
width under function, is required. The quality of the clasps are placed on the molar teeth. The clasp axis will be
impression of the sulcus directly influences the design of posteriorly placed and allow rotation of the anterior saddle
the bar. The bar should sit in the lingual sulcus with during function. To prevent this, indirect retainers are
minimal discomfort to the patient. An alternative solution placed on the most posterior teeth or the palatal connector
is to use a lingual plate, which lies on the tooth surface is extended towards the soft palate (Fig. 12.49). If this
above the cingulum.This is surprisingly comfortable to the is not possible, the lack of indirect retention will be a
patient but also results in total coverage of the periodontal problem. A path of insertion may also be considered to
tissues. This design should be selected with care and utilise any anterior buccal undercut that is present.
should not be constructed if there are problems with oral
hygiene. Other designs such as the lingual bar combined
Final considerations
with a continuous clasp or the use of a dental bar resting
on the cingulum surfaces of the teeth are complicated The overall design is checked and the occlusal relationship
castings and often prove to be poorly tolerated by the is reviewed to ensure that there are no interferences present.
patient. The design should be correctly drawn on an accompany-
ing piece of paper which should include details of all the
components and the teeth involved. Clarity is essential for
Indirect retention
the technician to understand the correct design and any
The RPD unit will have a tendency to rotate around an problems are resolved with direct communication. The
axis formed by the tips of the clasps. The eating of sticky design is also drawn on the cast to assist the technician.
foods will cause the saddle to move occlusally around this
clasp axis. It is analogous to a see-saw: if the saddle moves
upwards then the components anterior to the clasp will
rotate downwards. If there is no resistance to this move-
ment, damage to the underlying soft tissues may result. A
support unit, an indirect retainer, is placed anterior to the
clasp axis to prevent this movement (Fig. 12.48).
Indirect retainers do not prevent displacement towards
the ridge. This movement is resisted by the occlusal rest
on the abutment teeth and by the maximal extension of
the saddle. Decisions on indirect retention are made at the
end of the sequence of design stages. However, there are Clasp
two common design situations where it proves to be a axis
problem. In the lower bilateral free end saddle situation,
support units need to be positioned anterior to this clasp
axis and the example of a design with such indirect
retainers is shown in Figure 12.48.
The upper RPD replacing anterior teeth (Kennedy class
IV) is problematical. The forward position of the saddle
Indirect retainers
makes indirect retention of the denture a problem. The
174 design uses support from the posterior teeth and retentive Fig. 12.48 Example of an indirect retainer.
12 / The principles of tooth replacement
Clasp
Clasp axis
axis
(a) (b)
Fig. 12.51 (a) The canines are the last teeth remaining but have an unfavourable crown/root ratio. (b) Overdentures have been
constructed which completely enclose the remaining roots.
than this. The reduction in the crowns of the teeth may from the consumption of acidic drinks? The remaining
have occurred due to tooth wear from a combination of dentition has been restored and a definitive overdenture
erosion and attrition. In the elderly, where such tooth placed.
reduction has occurred, root canal treatment may not be
necessary. The removal of the roots will not benefit the
Clinical synopsis
patient and the overdenture is the best form of treatment.
Less common situations, such as partial anodontia, Successful overdenture treatment involves careful patient
cleft palate or loss of tooth crown substance in dentino- selection and treatment planning. Similar criteria to those
genesis imperfecta, may also require restoration using used in selecting bridge or partial denture abutments are
overdentures. The distinction between an onlay and an employed.
overdenture is not clear-cut and a potentially difficult
partial denture treatment, such as the restoration of a free
Selection of abutments
end saddle, may be helped by the coverage of a canine or
molar tooth with a reduced crown rather than a more When selecting the appropriate teeth for overdenture
involved crown restoration. abutments, there are many factors which influence the
In the case illustrated in Figure 12.53, an elderly patient clinician’s choice. The abutment teeth should exhibit good
has severe tooth surface loss. The aetiology of this wear periodontal health with adequate bone support. There
must be diagnosed before treatment is commenced. For should be minimal attachment loss and ideally they should
instance, is this wear a result of parafunction or erosion be surrounded by attached gingivae with no bleeding and
0.6 mm 5.2 mm
Fig. 12.52 The resulting bone loss over the 5-year period of the Crum & Rooney (1978) study (see text). 177
Restorative Dentistry
(a) (b)
Fig. 12.53 (a) This elderly patient has lost tooth structure over many years in the upper arch. (b) The remaining dentition has been
restored and a final overdenture placed. (Courtesy of Mrs E.A. McLaughlin.)
minimal plaque deposits present.The potentially damaging prior to manufacture of the overdenture. The prosthesis is
lateral loads are reduced with a more favourable crown/ completed towards the end of the treatment unless there is
root ratio. This can be achieved by reducing the height of a need for a provisional denture to stabilise the occlusion
the abutment tooth following root canal treatment. during treatment. Finally, the importance of follow-up,
Ideally, the abutments must be located on both sides of careful maintenance of the overdenture and regular review
the arch and evenly distributed. The best teeth for over- of the state of the oral tissues must be stressed to the
denture abutments are those with the largest root surface patient (see Box 12.11).
area such as canines and molars. If less favourable teeth,
i.e. lower incisors, are to be used for overdenture abut-
Types of overdenture
ments there should be a number of them together in order
to spread the loads. The teeth should be restorable and There are three methods of providing overdentures:
have enough supragingival tooth structure to allow them
to be used as abutments. If root canal treatment is required
• They may be placed immediately on reduction of the
teeth.
then the tooth should have canals that are readily negotiable
and the long-term prognosis of the tooth should be good.
• If the patient wears a removable partial denture, this
may be converted to an overdenture.
Although a tooth may be in a suitable position for use
as an abutment, there may be a large bony prominence
• Existing overdentures may require replacement.
that would preclude the use of a flange for the final A patient may already have an existing prosthesis, in
prosthesis. Such a situation may occur with the retention which case it is possible to convert the existing partial
of upper canines as overdenture abutments, where a large denture into an overdenture at the time of reducing the
bony eminence will often prevent the placement of a abutment teeth. Such dentures may be constructed at the
flange and/or detract from aesthetics. It may be necessary chairside or in the laboratory.
to incorporate a precision attachment and this will require
a tooth that has sufficient strength and root surface area to
support the increased loading. Box 12.11 Typical stages involved in overdenture
Overdenture treatment is sophisticated and may require provision
many clinical visits and there will be a high cost element.
1. Examination
All of this will influence the patient’s suitability for such
treatment and should be dicussed with the patient at the 2. Diagnosis, treatment plan
planning stage. 3. Preparatory treatment:
– periodontal
– abutments
Sequence of treatment – conservation
– root canal treatment
Following the drawing up of the treatment plan, preliminary 4. Other treatment
preparation may be started. Such treatment should include 5. Denture construction
any periodontal work and conservation and/or root canal 6. Follow-up and maintenance
treatment of the abutments. If advanced work is required,
178 such as copings or attachments, this should be completed
12 / The principles of tooth replacement
Caries
Root caries may take place on an unprotected root face.
Patients should be given correct dietary advice together
with advice on measures aimed at protecting the roots. It
has been shown that, in those patients who used a fluoride
gel daily, only 5% of teeth developed caries. This is in
contrast to those patients who did not use such a gel, in
whom 20% of the teeth developed caries.
Periodontal disease
Studies show that 35% of patients wearing overdentures
experience some loss of attachment. Furthermore, when
examining patients’ dentures, only 50% of their prostheses
were plaque-free. All these findings were related to poor
Fig. 12.56 Dental magnets placed on abutment keepers ready to
be cured to the denture. oral hygiene status of the patient.
Maintenance regime
When planning treatment for overdentures, the clinician
should consider whether the support will come from the It is imperative that the patient receives regular mainte-
teeth, the mucosa or a combination of the two. Increasing nance with plaque control of the abutments and care of
the support provided by the tooth root may lead to the root face. A fluoride gel, which can be placed in the
increased lateral stresses which may be detrimental in the recess of the denture where it contacts the abutments,
long term. A mucosal-supported denture receives increased should be prescribed. Regular oral hygiene appointments
retention and support from the greater amount of alveolar with the hygienist must be mandatory.
bone that is present. Within 1 month of preparing the abutment teeth for the
patient in Figure 12.57, the UR3 had developed recurrent
caries. The caries was removed and a new restoration was
Maintenance
placed. A strict regime of regular recalls was commenced,
The continual after-care of the prepared teeth underlying including application of a fluoride gel containing 0.05%
the overdenture is aimed at preventing both carious attack fluoride. Four years later, the abutment UR3 had an
and periodontal destruction, which would lead to root extended amalgam present but both root faces had been
extraction. This would then require modification or stable for this period of time. The darkening of the root
construction of a new overdenture.The prevention of such dentine is a result of the high levels of fluoride. In contrast,
problems should form part of the management in this the patient shown in Figure 12.57(b) was not well
restorative procedure. controlled and after placement of the overdentures did not
(a) (b)
Fig. 12.57 Both these root faces developed caries. The root face in (a) has been restored and a strict regime of oral hygiene and topical
180 fluoride instigated. In (b) the root required extraction.
12 / The principles of tooth replacement
return for review. Three years later the root face had
recurrent caries and the root required extraction.
Summary
Overdentures are a useful form of restorative treatment
when replacing teeth. They are indicated where teeth are
to be covered or where there is crown loss which is not
restorable by other methods. The procedure requires the
careful interaction of periodontal treatment, good operative
procedures and root canal treatment, thus allowing the
final placement of the removable prosthesis to be success-
ful.This success is built on appropriate treatment planning
and a high quality of clinical care. As with any advanced
procedure, it is important to maintain a careful review of
the ongoing function of such treatment.
IMMEDIATE DENTURES
Introduction Fig. 12.59 Radiograph shows poor bone support for the anterior
teeth.
An immediate denture is a denture that is made prior to
the extraction of the natural teeth, which is inserted into
the mouth immediately after the extraction of those teeth.
It is seen as a provisional prosthesis (Figs 12.58–12.61).
The provision of an immediate denture has may advan-
tages for a patient including maintaining the soft tissue
contour of the face and helping the patient at a time when
losing a tooth or teeth may be a traumatic and difficult
emotional process. An immediate denture has the big
advantage in that it aids in the process of adaptation to
dentures. As patients’ dental health has improved, the
provision of immediate dentures has changed from exten-
sive removal of all the teeth to simple additions to existing
dentures. Once again such dentures are seen as
transitional in nature (Figs 12.62–12.64).
They are used to assist in aesthetics or mastication over
a period of time (6 to 12 months) prior to provision of a
Fig. 12.60 The teeth have been removed.
Treatment planning
The treatment planning of the patient will dictate which
of the existing teeth require extraction (Box 12.14). For
instance, it may not be necessary to extract the teeth as
they may be used for overdenture abutments or if they
have a poor prognosis they may be temporarily kept for
the transition to denture wearing. Other options include
extracting teeth of poor prognosis and not fitting the
Fig. 12.58 The patient has several anterior teeth that are causing denture for approximately 6 months. This is only done for
problems. posterior teeth, which allows resorption to take place and 181
Restorative Dentistry
Fig. 12.61 The immediate denture has been placed over the
extraction sockets.
Mechanistic approach
Box 12.15 Review timetable
In this approach the artificial teeth will be set up on the
24 hours Simple check on patient status – adjustments crest of the remaining alveolar ridges. The concept here
geared to make patient comfortable is that the underlying ridges will take the occlusal stresses
1 week More involved check of patient status – during function. This is simple and straightforward to
thorough examination followed by understand. Unfortunately it does not consider the
adjustments of impression and occlusal
surfaces
biological consequences of adopting such an approach in
the longer term.The edentulous ridge will resorb over time
1 month Review for further adjustments. and therefore their position will change. The associated
Any placement of temporary or permanent
linings should be delayed until 3 to soft tissues will also be compromised. For instance in the
6 months unless absolutely necessary lower arch, the mechanical positioning of the teeth on the
6 months Review the need for reline of denture as
ridge will often produce an occlusal form that takes no
much of the resorption will have taken account of the positioning of the tongue. This may lead to
place soreness of the tongue and instability of the lower denture.
12 months Provision of new dentures
Copy dentures
Many patients present with dentures that they have been
wearing for several years and are generally comfortable
COMPLETE DENTURES with them. Their presenting problems are often related
to looseness or difficulty with eating. The patient has
Although patients are keeping their teeth longer and the developed good neuromuscular control over the years.
demands for fixed prosthodontic solutions in restorative Therefore the polished surfaces of the dentures (i.e. the
dentistry are growing, there will still remain a sizable general denture form) are correct. The problem is either
number of patients who are edentulous. This group of related to the artificial teeth that have worn leading to a
patients will generally be elderly and with current life poor occlusion or the impression surface no longer corre-
expectation increasing will live without teeth for a sub- sponds to the ridge shape that has resorped over the years.
stantial number of years. This will pose several problems It may be sufficient in such cases to undertake a copy
including the ability of the patient to adapt. Also the skill denture technique (Fig. 12.65).
base of clinicians who are capable of providing such treat-
ment will slowly decrease as the demands for other types
Biometric
of treatment increase. In short complete denture cases will
become more clinically challenging. This text can only Watt and MacGregor demonstrated in the early 1960s that
serve as an introduction to the provision of complete den- there is a remnant of the palatal gingival vestige that
tures and the reader is advised to further such knowledge remains as a stable anatomical structure. This may be
by the use of postgraduate courses following graduation. identified on the upper edentulous denture-bearing area
A simplistic way to consider complete dentures is to even after many years of bone resorption. This vestige may
look at how they are designed in a similar manner to then be used to assist in the placement of the artificial
partial dentures. This concept of designing then assists teeth. The subsequent guidelines can prove to be very
during the diagnosis of the patient’s problem and subse- useful in knowing where the teeth should be placed. Further
quent treatment planning. Complete dentures may be reading on this technique may be found in the further
considered in four different ways (Box 12.16). reading section at the end of this book (Fig. 12.66).
184
12 / The principles of tooth replacement
Functional approach
Assessment of the patient
The neutral zone technique is an alternative approach for
the construction of lower complete dentures. It is defined As in any patient consultation, a careful history is essential
as the area between the tongue on one side and the cheeks and leading questions will often open up a more detailed
and lips on the other where soft tissue displacing forces are assessment that will have consequences for the subsequent
least. It is most effective for dentures where there is a treatment of the patient. Asking the patient a few leading
highly atrophic ridge and a history of denture instability. open questions assists in drawing up the picture of the
The technique aims to construct a denture that is shaped patient’s problems. For instance: how many dentures have
by muscle function and is in harmony with the surround- been made for you? When did you become edentulous?
ing oral structures. The technique is by no means new but Which denture has been the most successful? The
is a valuable one to use in difficult cases (Fig.12.67). scenarios can be many and varied but the following are
examples. A patient who has been edentulous for many
years where each denture has lasted well over 5 years may
Conventional approach to complete dentures
be considered to be a relatively successful denture wearer.
The following description of examination and subsequent However, a history of a couple of years of edentulousness
treatment follows a traditional outline of treatment. with a series of dentures that have not functioned well will
1cm
Incisive papilla
Former position
of canine
Palatal gingival
vestige PGV
Fig.12.66 This is an edentulous arch and the overlay shows some of the biometric guidelines that may be used for tooth positioning. 185
Restorative Dentistry
send warning signs. These typical examples will imme- palate), and any soft tissue that is present. The health of
diately give a clinical impression to the operator to what the tissues should also be noted. Any inflammation over
has gone before and how it will influence the subsequent the area that the denture fits indicating the presence of
success. The provision of complete dentures is an area of Candida albicans in the denture is recorded.
dentistry where the psychological profiling of the patient The lower edentulous ridge is examined and an estima-
is an important component of the diagnosis and treatment tion of its shape, health and the bone quality is made.
planning. Figure 12.68 shows examples of upper and The previous dentures, if present, are then examined
lower edentulous arches. and placed in the mouth. These will provide important
The previous medical history is taken as outlined in clues to both the clinical problem and methods of how
Chapter 3 (p. 15). However, many of these patients will be to possibly resolve the situation. The denture may be
elderly and will be taking a complex cocktail of medica- examined in the following manner.
tions. One of the common problems with many of these Impression/fitting surface – the extensions of the border of
patients is that the variety of drugs they are taking may lead the denture are examined to determine if it is adequately
to a reduced salivary flow.The consequences of this include extended. Overextension may reveal pain and soreness
a dry mouth which may lead to poor denture retention. whilst underextensions may relate to the complaint of
Social history may reveal more details of their personality looseness and lack of retention.
and other non-dental considerations which may have a Occlusal surface – when the patient closes the teeth
direct impact on the treatment. As such patients are elderly together, the maximum number of teeth should meet. If
there may be pressures such as transport arrangements, the patient is then asked to move the teeth over one another
care of elderly relatives, etc., all of which may have an this should occur in an even gliding movement without
impact on treatment. any cuspal interference. If this is present then the teeth are
The first visit with a patient requiring complete dentures in occlusal balance. The lack of such balance will often
is an opportunity to find out why the patient wishes new present as either pain underneath the denture or looseness
dentures and to diagnose any problems. At the end of the during function. Often clinicians will look to the fitting
visit, as a clinician, you should be in a position to draw up surface of a denture as to the source of such discomfort or
a treatment plan. The subsequent examination allows you denture instability without considering occlusal discrepancies
to bring in the patient’s presenting complaint with the as the potential source of the problem.
clinical presentation. Polished surfaces – the tongue, lips and cheeks contact
the denture whilst in function and may be major factors in
retaining and stabilising it during function. If the surfaces
Examination
are not in balance with such soft tissues then this will
The examination of the edentulous patient will include present as denture looseness. An assessment of the lower
visual inspection of the soft tissues. This will be followed denture in the neutral zone is made.
by examination of the denture-bearing tissues which will An estimation of the vertical dimension of occlusion is
include the upper ridge, where the shape of the ridges is made. Typically patients require approximately 2 to 3 mm
observed and noted (i.e. ‘u’or ‘v’ shaped, high or low space between the teeth at rest.This interocclusal clearance
(a) (b)
186 Fig. 12.68 (a) and (b) Examples of upper and lower edentulous arches.
12 / The principles of tooth replacement
(freeway space) may be measured with a Willis bite gauge The period of edentulousness has allowed the tongue to
(Fig. 12.69). If there is excessive freeway space then this spread laterally and this will compromise the position of
will lead to instability and looseness with the patient the teeth. It is possible to identify several structures on the
appearing overclosed. Too little or no freeway space will upper denture-bearing area including the incisive papilla
not allow the patient to rest and the underlying tissues will and the palatal gingival vestige. These may be useful as a
be under constant stress. This will lead to discomfort and potential guide to positioning the teeth. For instance, in
may also interfere with speech. general the central incisors should be placed approximately
Finally the most difficult assessment to make is the 1 cm in front of the posterior border of the incisive papilla.
psychological profile of the patient and their ability to cope This has been determined to be close to the previous
or adapt to the wearing of dentures. Sometimes the position of the natural incisors.
complaint is out of proportion to the clinical results found The lower denture-bearing area reveals a narrow ridge
following clinical examination of the dentures. Alterna- and the tongue spread may make the positioning of the
tively the remaining hard and soft tissues do not lend posterior teeth very difficult. The subsequent determina-
themselves to the provision of dentures. It is useful to tion of the neutral zone for tooth placement may well be
explain at this stage to the patient what complete dentures difficult.
are ‘A replacement of no teeth’. Patients’ expectations run The diagnosis was an edentulous situation where com-
high and simple communication of why there may be plete dentures were required. However, care and attention
difficulties with the wearing of dentures following the loss to the placement of the artificial teeth in relation to the
of natural teeth is an important factor in the overall care of soft tissues is important.
the patient. The treatment plan was to construct the complete den-
The clinician will by now have made an assessment of tures using a conventional approach but using biometric
the patient and a diagnosis is made of the clinical problem. guidelines to assist in the provision of the complete den-
From this diagnosis a treatment plan is drawn up as to the tures. A decision on the placement of the lower teeth would
overall clinical techniques that will be used. be made at the registration stage (Box 12.17).
Fig. 12.69 The free space is being measured with a Willis bite
gauge. Typically the difference from resting position and occlusal Fig. 12.70 An upper preliminary impression that has been taken
contact position is 2–3 mm. in impression compound. 187
Restorative Dentistry
Master Impressions
Fig. 12.72 The lower impression shown has been taken with zinc
A laboratory request for the provision of upper and lower oxide/eugenol.
light-cured special trays is made. The upper is spaced
(2 mm) and the lower is close fitting. The upper tray is is minimal saliva contamination during the taking of the
tried into the patient’s mouth and checked that the exten- impression.
sions relate to the functional depth of the sulcus. Correc- In order to protect the representation of the sulcus on
tions may be made to the tray with a suitable autopoly- the dental cast, red carding wax is added to the lower
mersing acrylic resin. A portion of ‘carding’ wax is placed impression; this creates a land area when the impression is
on the impression surface of the tray to maintain the neces- poured. The process is called beading.
sary spacer present for the alginate impression material.
The upper impression is taken with a low viscosity
Registration
alginate (Fig. 12.71). This is a mucostatic material, which
gives detailed reproduction of the upper denture-bearing This is the most involved stage of the construction of
area. It is dimensionally accurate but not dimensionally complete dentures. There are several important objectives
stable and therefore the subsequent cast should be poured to be achieved at this clinical stage (Box 12.18).
straight away. The laboratory will have been asked to provide wax
The lower special tray is constructed as a close fitting occlusal record rims. The upper is strengthened by the use
for a wash impression with zinc oxide eugenol (Fig. 12.72). of a shellac or polystyrene base and the lower will have a
The close fitting special tray provides a mucodisplacive wire strengthener. Do not be tempted to use all wax bases
force on the lower ridge. Zinc oxide-eugenol is a mucostatic as they distort. Occasionally heat-cured (i.e. processed)
impression material that provides an accurate represen- bases may be made from the casts. These are useful if you
tation of the fine detail of the mucosa. Other materials want to know at an early stage how your denture will fit.
that may be used include medium-bodied silicone. The However, the cast will no longer be with you and if exces-
additional benefit of using a close fitting tray is that there sive trimming is required then you will quickly learn that
wax is much easier to adjust than acrylic.
It is useful to consider the registration stage in three
separate stages.
188 Fig. 12.71 An upper impression that has been taken in alginate.
12 / The principles of tooth replacement
dentures and then adding modifications to the resulting tion requires long-term care and this requires high patient
templates. Registration follows similar principles as those cooperation. This also makes such treatment costly for the
described in this text. Impression taking is relatively patient in comparison to more conventional forms of tooth
straightforward as the duplicate dentures will act as a replacement, such as dentures or bridges. Furthermore,
special tray allowing wash impressions to be taken. The patient exceptions may be high and it is often not possible
neutral zone technique is introduced at the registration to restore every mouth using implants. Often situations
stage of denture construction. Once the upper rim is where an implant is suitable can be resolved with the use
trimmed the lower rim is built up in a suitable mouldable of a bridge or RPD. The clinician must prevent a denture/
material such as the tissue conditioner Viscogel. This is bridge problem becoming an implant problem through
allowed to mould to the neutral zone as the patient is incorrect treatment planning.
asked to speak, sip some water, thus allowing the tissues to The success of such treatment is assessed by the follow-
influence the shape of the rim. The teeth are subsequently ing four clinical parameters:
set up within the space created by this rim.
• implants are clinically immobile
• no peri-implant radiolucency
Final considerations • vertical bone loss less than 0.2 mm/year
• no pain or infection.
If there are some teeth left then these may be root filled
and overdentures provided. If the present techniques do Modern implantology is very successful but there were
not provide satisfactory retention and stability of the many other methods used by clinicians in an attempt
dentures then an implant-supported overdenture may be either to improve denture-wearing or to provide support
considered for the patient. for a crown and bridgework. Initially, surgeons used pre-
prosthetic surgery to improve the denture-bearing area.
These were mainly soft tissue operations and included
INTRODUCTION TO IMPLANTS vestibuloplasties which aimed to improve the buccal
sulcus. Such operations had mixed success rates.
The use of implants in the field of dentistry has grown Early techniques focused on subperiosteal implants.
rapidly since its introduction in the early 1980s. This First the mucosa was reflected and an impression of the
specialised area is generally considered a postgraduate bone made. A framework was constructed and placed
subject and the majority of the work takes place in the under the periosteum. These failed as the body attempted
private sector. However, a small percentage of dental to encapsulate the metal framework with epithelium, and
implants are placed within the NHS, mainly for priority inevitably they were lost due to infection. An early fore-
cases and for the purposes of clinical trials. This section runner of the modern implant was the blade implant.
serves as an introduction to the subject and aims to These were hammered into the bone, which was allowed
encourage further reading. to grow around the design, thus providing anchorage. The
metal used was stainless steel and these implants had a
poor success rate, with infection being the usual reason for
Osseointegration
failure.
A successful dental implant must be biologically accepted Blocks or crystals of hydroxyapatite were used in an
in the bone and is termed osseointegration. There is attempt to augment the resorbed ridge and met with limited
direct apposition of the bone to the implant material and success. These blocks were of limited value, as they tended
there is no intervening fibrous tissue present. Osseointe- to be unstable and migrate under the periosteum. This
gration is a misnomer because there is no actual integra- resulted in a flabby rather than a firm denture-bearing area.
tion occurring between implant and bone, only close It was the studies undertaken by Professor Brånemark
apposition of the bone to the implant material. There are and his team in the early 1980s that introduced the concept
many materials which are biologically acceptable and can of osseointegration into implantology. Their work showed
serve as dental materials. However, titanium metal is the that implants constructed from titanium and placed under
material of choice owing to its high compatibility and the a certain clinical protocol brought about high success. The
ability to machine the material into the required shapes. following is a brief description of these techniques.
The titanium oxide surface layer makes the material
relatively inert and also provides a degree of bonding with
Clinical procedure
the bone.
The main advantage of an implant is that it replaces lost Most modern implant treatment consists of a two-stage
teeth with a non-removable restoration. In doing so, it procedure. After treatment planning, the bone is surgically
helps to restore function, aesthetics and speech. Although exposed and a pure titanium metal implant is placed
successful, there are some disadvantages associated with therein. This is left buried in the bone and unloaded,
the treatment. The provision of an implant-borne restora- usually for 3 months in the mandible and 6 months in the 191
Restorative Dentistry
Treatment planning
maxilla. After this healing period, the implant is uncovered
and the final prosthesis is placed. There is an exception The best planning is via a team approach. This should
with one system (Straumann/Bonefit) which allows the ideally involve the oral surgeon and restorative dentist
implants to communicate with the mouth during the (specialities generally involved are fixed and removable
healing phase and this enjoys similar rates of success. prosthetics and periodontology). The dental technician
Professor Brånemark based his clinical protocol on expe- should be involved in the planning process and the
rience gained over a 10+ year period of implant treatment hygienist during the maintenance phase.
in over 700 patients between 1965 and 1982 and demon- Treatment planning is very important, as is a good
strated a high success rate. It paved the way for extensive history.The clinician can quickly select on the psychological
research and clinical reports which demonstrated the profile and personality of the patient. The patient’s attitude
success of the implant technique. It is now known that the to dentistry and motivation towards a long and intense form
success of osseointegration in well controlled clinical trials of treatment are also important. A clinical examination is
is > 95% in the mandible and > 90% in the maxilla. The undertaken followed by radiographs such as sectional CT
lower success in the maxilla appears to be related to the scanning to assess the bone levels. An acrylic stent may
bone density and structure. be used to assist this process, and can be converted to a
surgical stent to assist the oral surgeon (Fig.12.77).
All surgical/prosthetic implant kits come with a selection
Present implant systems
of burs and various instruments for use with fixture and
Although the implant is made of commercially pure abutment placement. The burs supplied have a marking
titanium, many of the systems that are available attempt to system to allow the clinician to determine the depth of
improve osseointegration by increasing the surface area hole cut in the bone. Ideally a fresh bur should be used for
(Fig. 12.76). This is done by: each patient.
• providing a hollow screw
• spraying implant surface with titanium plasma hydro- Surgical procedure
xyapatite
A mucoperiosteal flap is raised and the tissues are
• surface roughening by titanium blasting
reflected to reveal the underlying bone. The holes are cut
• providing external threads on the implant.
using a saline-cooled bur driven by a torque reduction
The final restoration may be either a fixed or a removable handpiece. The cutting temperature must not exceed
prosthesis, and fixed restorations are all implant-supported 60°C, otherwise the bone cells will be destroyed leading to
designs.There are also specialised single tooth restorations. implant failure. Depending on the system used, the hole
The removable implant designs are based on traditional may either be tapped for placement of a threaded implant
overdenture procedures and may be retained by the use of or receive a self-threaded implant. A depth gauge is used
studs, bars and magnets in a similar fashion to conven- to verify the correct length of implant to be placed. The
tional overdentures. implant is handled by instruments and delivered to the
surgical site. The mucoperiosteal flap is then closed and
the area left to heal. The implants should not be loaded,
thus enabling osseointegration to take place.
(b)
Fig. 12.78 (a) Implants correctly placed with cover screws prior to Fig. 12.81 Four implants joined by a bar. (Courtesy of Professor
closure. (b) Radiographs of the implants in situ. W.R.E. Laird.) 193
Restorative Dentistry
following conventional clinical and laboratory procedures. housing situated in the denture and the stud attached to
A transfer coping at the impression stage is passed to the the abutment is illustrated in Figure 12.82.
laboratory to assist in the crown manufacture. Magnets provide a simple and effective method of retain-
ing overdentures. They are made from iron–neodymium–
boron encapsulated in a steel housing and are retained in
Overdentures
the denture. They attach to a ferrous keeper which is
Implant-borne overdentures offer a simple and effective attached to the implant abutment (Fig. 12.83). Up to two
method of retaining dentures. This is done using a bar, to four implants may be used for magnetic retention of the
studs or magnets. A bar prosthesis provides positive reten- denture in the lower jaw.
tion and stability to the complete lower overdenture. The
clip is retained in the denture and the bar is linked to
Failure of implants
between two and four implants in the lower jaw (Fig.
12.81).The retentive clips are held in the denture.The bar Plaque and calculus will attach to titanium implants,
is attached to caps which are retained by screws on the which will lead to inflammation of the tissues (Fig. 12.84).
abutments. It is important that good oral hygiene is All these situations respond to increased awareness of oral
maintained around the abutments, especially at the join of hygiene procedures. An early complication of the implant
the bar. placement is infection. This occurs within a few days of
The ball-and-socket attachment relies on the frictional placement and will often lead to non-integration of the
attachment of the gold housing over the stainless steel ball. implant. Other common failures are related to the attach-
The grip of the housing may be adjusted by opening or ments. Single tooth crowns and bridges may fail due to
closing the gold wings. Sufficient retention may be gained
by the use of two implants. A clinical picture showing the
(b)
Fig. 12.82 (a) Two implant abutments with stud attachments. Fig. 12.84 Patients may receive implants but poor after-care leads
194 (b) The associated clips are cured into the denture. to failure.
12 / The principles of tooth replacement
195
Restorative Dentistry
SUMMARY
196
13 Integrated treatment
planning
Simple restorative treatment plans 197 subsequent visits.The most useful clinical tools in this case
Complications 197 are simple plaque and bleeding indices. The patient may
Overview of the specialities and their influence on the require a scaling with the removal of both supra- and
treatment plan 198 subgingival calculus followed by polishing of the teeth.
Periodontal procedures 198 Simple plastic restorations may be undertaken and usually
Simple operative procedures 198 the patient is discharged with a recall being set for
Endodontic therapy 198 6–12 months. Such treatment planning is simple and
Fixed and removable prosthetics 199 undemanding and the majority of regular attenders fall
Maintenance 199 into this category.
Modifications to initial treatment planning 199
Case studies 200
Complications
This simple approach will change if the patient presents in
pain or has other problems such as lost fillings or fractured
Restorative dentistry covers many different disciplines. It teeth. The emphasis of any treatment planning must
is relatively easy to consider undertaking treatment such include aims to eliminate the immediate cause of this pain.
as root canal therapy, restorations involving occlusal or Once this is solved, the routine treatment can be carried
proximal surfaces, or the provision of a removable partial out. Elimination of the pain may well require temporisa-
denture. However, bringing all these events together in a tion. Decisions are made to resolve the situation and then
logical clinical sequence is the decision process involved in the clinician can move back to the simple plan. An example
a restorative treatment plan. There may be many different of such emergency treatment is the construction of an
approaches to similar problems and these can vary from immediate denture prior to the removal of a tooth. This
simple monitoring to more elaborate restoration of an may involve the addition of an artificial tooth to the patient’s
occlusion. When considering a treatment plan, the skills denture. Once resolved, it is then possible to return to
and experience of the treating clinician are applied to the simple treatment planning, eventually remaking the den-
problem, at the same time taking account of the patient’s ture. Emergency treatment planning can involve different
wishes and demands. parts of restorative dentistry.Teeth marked down for extrac-
tion are removed. Simple root canal therapy is started and
the patient is made comfortable. It may be possible to
SIMPLE RESTORATIVE TREATMENT PLANS complete the root filling quickly, but usually the root canal
is dressed with calcium hydroxide and stabilised. Gross
Simple restorative plans often arise when a patient is a caries is removed from the teeth, which are then stabilised.
regular attender and there are no presenting complaints. The majority of treatment plans will include an initial
Such treatment planning will often contain the following phase of periodontal treatment. Such clinical work can
items of treatment. In the first instance, the patient will give the clinician an idea of the patient’s motivation and
require oral hygiene instruction. The teeth are disclosed this may influence subsequent treatment. This phase will
and the patient is shown an appropriate toothbrushing enable the clinician to motivate the patient and work at
technique. If there are concerns about the level of oral establishing a baseline from which further complicated
hygiene, it will be necessary to monitor the patient over procedures can be done.
197
Restorative Dentistry
198
13 / Integrated treatment planning
Casts are important aids in treatment planning. They may 1. Dietary advice (usually over three visits)
require two visits in order to obtain secondary impressions 2. Temporise/stabilise gross caries
which are made from special trays constructed on the 3. Reassess after a short recall (3 months)
preliminary casts. The master casts need to be articulated
on a semi-adjustable articulator and this information is
obtained from a registration and the use of a face bow
recording. Such a diagnostic procedure will assist the
clinician in the formation of a treatment plan for a complex
case. As the case proceeds, the original treatment plan may
need to be revisited using the articulated casts to assess the
need for fixed and removable designs. It is at this stage that
it will be possible to draw up the definitive denture design.
Following this, the advanced crowns can be undertaken
followed by the provision of the removable partial denture.
MAINTENANCE
CASE STUDIES
The discussion above gave some guidelines to approaching
the integration of the different specialities that are involved
in restorative dentistry. However, each patient is very
different and it is difficult to cover all scenarios the clinician
may come across. The following pages present a series of
Fig. 13.2 Erosion occurring on a tooth which has left the
cases which involve different approaches to restorative amalgam proud.
treatment planning together with their eventual outcome.
These cases should serve as an example of how to inte-
grate the different specialities into a logical treatment plan. Case 1
Each case is discussed using a layout that follows the sub-
headings (and their abbreviations) for examining a patient Mrs PS (25 years old)
that were introduced in Chapter 3 (Box 13.4).
RFA. This female patient was referred by her local dentist
for replacement of her upper anterior crowns. They had
been replaced 1 year earlier due to the poor gingival
condition, which was thought to be due to poor crown
Box 13.4 Aide-memoire
margins. The new crowns had not improved the situation.
Referred by: Reason for referral:
CO. The patient complained of gums that bled on
Date of referral: Date seen: brushing around the upper anterior crowns.The rest of the
mouth did not have any symptoms (Fig. 13.3).
1. Reason for attendance RFA
HPC. The original crowns had been provided 5 years ago
2. Complains of CO
as the teeth were heavily restored.The problem had occurred
3. History of present complaint HPC
shortly after the original crowns were fitted.
4. Medical history MH
5. Dental history DH MH. There was no relevant medical history.
6. Personal/social history PH/SH DH. She attended regularly for treatment. She received
7. Examination routine care from her dentist, including scaling and polishing
(a) Extraoral EO every 6 months.
(b) Intraoral IO
Soft tissue exam
Hard tissue exam
Periodontal assessment
BPE screen
Assessment of edentulous areas
Assessment of removeable/fixed appliances
Static/dynamic occlusion of teeth/prosthesis
8. Special investigations
9. Diagnosis
10. Treatment plan
11. Signature
*An 11-point structure to history-taking, examination, diagnosis
and treatment planning with appropriate abbreviations (these may
differ between teaching institutions but the general approach will
be similar)
(a)
Periodontal assessment
BPE:
4 3 4
4 2 4
Conservative assessment
The patient had few restorations present and these were in
a satisfactory state.
(b)
Static/dynamic occlusion of teeth
The occlusion was normal with no significant deviations.
Diagnosis
A diagnosis of early adult periodontitis was made, asso-
ciated with the subgingival crown margins.
(c)
Treatment plan Fig. 13.4 Periodontal excisional flap to reduce gingival height to
The main objective of treatment was to provide an exci- the level of the crowns.
sional flap to move the gingival margins apically away from
the edges of the crowns. This would permit healing of the
5. Replace the crown if the revealed margins are seen to
grossly inflamed gingival tissues.
be deficient.
Therefore, the following treatment plan was drawn up:
1. Check on home care measures
Discussion
2. Scale and polishing
3. Periodontal excisional flap to reduce the gingival height Another possible treatment would be to remove the crowns
to the level of the crowns (Figs 13.4 a, b, c). and replace them with ones with excellent margins. This,
4. Follow-up and maintenance (Fig. 13.5). combined with good subgingival plaque removal, will result 201
Restorative Dentistry
Case 2
Conservative assessment
Mr KG (23 years old) The patient had one restoration present. Frank caries was
observed in the LR56 and the UL7.There was evidence of
RFA. The patient attended the emergency department of erosive tooth wear which was most evident on the lower
his own accord. anteriors.
(d) (e)
(f)
Fig. 13.7 Radiographic examination of Case 2. 203
Restorative Dentistry
6. RCT LR1 HPC. There was a 2-year history of bleeding gums and his
7. Assess RCT LR6 or extraction own dentist had prescribed a course of antibiotics for an
8. Aesthetic restorations on lower incisors intraoral swelling.
9. Study models for patient and reassess for possible
MH. There was no relevant medical history.
advanced restorations
10. Recall. DH. The patient was a regular attender every 6 months.
PH/SH. He brushed twice a day and for interdental
Discussion cleaning used a bottle brush and floss. He smoked three
cigarettes per day.
The clinical pictures show that the acid erosion (from cola)
had affected many teeth, as seen by their glassy appearance, Extraoral. No problems with TMJs and no lymph-
and ridging of the incisal tips.There is little staining on the adenopathy.
smooth surfaces, in spite of inadequate oral hygiene. This
Intraoral. Subgingival calculus present, swelling LL2 region.
suggests that regular ‘acid washing’ was present, prevent-
ing stain from forming. The treatment plan includes both Teeth present:
dietary advice and the use of study models, which are a
87654321 12345678
record of the tooth surfaces and can be examined at subse-
87654321 12345678
quent appointments.
Periodontal assessment
Outcome
BPE:
The patient had the teeth removed and is undergoing
treatment successfully. The RCT of the LR1 showed that 4 4 4
there was an extra canal present that had not been treated 4 4 4
(45% of lower central incisors have an extra canal). The
patient has complied with dietary advice but the real
evidence will be the observation of no change with silicone Conservation assessment
index impressions taken at review appointments and
Some small amalgam restorations were present. No active
compared with the patient’s study models.
caries was noted.
Attendance and motivation were high and eventually
the molar RCT was undertaken towards the end of the
treatment plan. If compliance had been low, the option Occlusal relations
of extraction would have been considered. This plan
The patient had a class I relationship. On right lateral
shows the need to stabilise dentitions, instigate preventa-
excursion there was contact on LR2 and on left lateral
tive regimes and undertake more complicated procedures
excursions on LL2. Both the LL2 and LR2 were over-
such as molar RCT later in the treatment plan.
erupted by 1 mm.
Special investigations
Case 3
Pulp test. LL2 positive, LL3 negative, LL4 positive.
Mr NS (26 years old) Radiographic examination. Bone loss 60–70% generally,
50% on LL3. There was a periradicular radiolucency
Endodontic problems may arise in association with on LL3.
periodontal disease. Examples include sensitivity due to
exposed cervical dentine or an abscess. In such situations
Diagnosis
it is important to analyse the situation in a systematic
manner as the abscess may be periodontal or endodontic 1. Rapidly progressive periodontitis with secondary
in origin. occlusal trauma
2. Perio-endodontic lesion LL3.
RFA. This man was referred to the periodontal depart-
ment for management of his periodontal disease.
Treatment plan
CO. One year previously the patient had been advised by
his own dentist that he had gum disease. He was aware of The objectives of the treatment plan were to stabilise the
an abscess in his lower jaw near the front of his mouth and periodontal condition and provide endodontic treatment
204 this was troubling him. LL3:
13 / Integrated treatment planning
1. Reinforce oral hygiene with attention to interproximal is an apical delta.The periradicular lesion lay on the mesial
cleaning aspect of the root, reflecting the position of the portals of
2. Full-mouth fine scaling exit/entry.The LL3 was not carious but the degree of bone
3. Endodontic treatment LL3 loss could have exposed the more coronally placed portals
4. Review oral hygiene with view to further periodontal of exit/entry. This, together with the previous periodontal
therapy. instrumentation, may have resulted in pulp necrosis.
The obturation film shows sealant overfill through the
portals of exit. The coronal and middle third communica-
Discussion
tions lie adjacent to the periodontal pocket. The follow-up
The radiographs of this patient show an example of complex radiograph shows bone infill with an absence of sealer
root canal anatomy (Figs 13.8–13.10). The LL3 had two laterally (Fig. 13.11). The infill has occurred as a result of
root canals, which merge apically. One lateral canal can be managing the microbiological problem in the root canal.
seen in the coronal third, two in the middle third and there
Outcome
This case illustrates that healing will occur in the presence
of excess filling material, provided treatment is directed at
microbiological management. It also highlights the impor-
tance of a systematic approach and the use of appropriate (a)
special tests to reach a diagnosis.
Case 4
Special investigations
the teeth as they met violently in occlusal contact at the time
Radiographic examination. Anterior long cone periapicals of the fall. A decision was made early on to assess which
and a panoramic radiograph were taken and these are teeth were not restorable and this was immediately apparent:
shown in Figure 13.13. A hairline fracture is associated UR4, 5 and 6 were removed by a minor oral surgery proce-
with the lower incisors. UR4, 5 and 6 have fractures, which dure. Fortunately aesthetics was not a problem and there
are at or below the bone level with evidence of pulpal was not a need to provide an immediate replacement.
involvement. LR6 and LL6 crowns are fractured with no Following healing the patient can receive hygiene treat-
pulpal involvement. LL7 has occlusal caries. ment after which the teeth can be restored. Before advanced
restorations are carried out, impressions are taken and the
Thermal and electrical pulp testing. This revealed that
resulting casts are articulated.The provisional RPD design
all teeth with the exception of the severely fractured teeth
is made and then the crowns can be commenced. Finally
were responsive to testing.
the RPD is constructed. In this case it was not possible to
fill the space with a fixed bridge as the span was too large.
Diagnosis Furthermore, the UR3 was intact and the UR7 had been
fractured in the fall and therefore there was a question-
Fracture of mandible and several teeth due to fall after
mark over its ability to support such a bridge design.
fainting. Gingivitis is also present.
Outcome
Treatment plan
Although a well-thought-out treatment plan was drawn up,
The main objective of treatment was to remove those teeth
there were complications during treatment.This was related
which were severely fractured and restore function and
to the LL6 and LR6. A few months after the accident both
aesthetics of the other teeth in the arches. Therefore the
teeth became sensitive and caused pain and discomfort.
following treatment plan was drawn up:
The LL6 started to give pain of a throbbing nature. This
1. Investigate UR 4, 5 and 6 with a view to their imme- was worse on biting and on presentation had interrupted
diate extraction sleep. A diagnosis of acute apical abscess was made. Root
2. Instigate oral hygiene procedures with a scale and polish canal treatment was commenced but over four visits it was
3. Restore UL6, LR6, LL6 and UR7 with amalgam not possible to achieve a dry and symptom-free mesiolingual
4. Articulated study casts for upper partial denture canal. It was concluded that the root might be fractured
5. LR6, LL6 and UR7 full veneer gold crowns and the tooth was extracted. A month later the LR6 gave
6. UL1 replace porcelain jacket crown similar symptoms and this time the patient requested
7. Upper cobalt/chromium removable partial denture extraction in preference to the RCT option. All other
(RPD). restorative treatment was completed and the RPD was
provided. The final result is shown in Figures 13.14 a, b, c.
Discussion
Case 5
The patient received the initial emergency treatment at a
local casualty department. Radiographs were taken to
assess for any facial fractures and the midline fracture was
Mr IE (50 years old)
considered to be stable so that dental treatment could be
RFA. Practitioner referral requesting a periodontal
carried out. The impact on the chin resulted in shearing of
assessment of the patient and a request for treatment.
CO. The patient complained of loose teeth and poor
aesthetics.
HPC. The problem of loose teeth had become apparent
over the last few months. However he had had several gum
infections which had been treated with antibiotics.
MH. There was no relevant medical history.
DH. Not a regular attender but has started to visit the
dentist due to concerns about his teeth. He needed to have
his upper posterior teeth removed in the last few weeks
due to looseness and infection.
PH/SH. The patient brushed occasionally but tended to
Fig. 13.13 Radiographic examination of Case 4. rely on mouthwashes. He smoked 20 cigarettes per day. 207
Restorative Dentistry
Periodontal assessment
BPE:
4 4 4
4 4 4
Conservative assessment
The patient had few restorations present and these were in
a satisfactory state, although the lower restorations were
poorly contoured.
Diagnosis
A diagnosis of chronic adult periodontitis was made.
(a) (b)
(c) (d)
Fig. 13.15 Clinical photographs of Case 5 pre-treatment.
1. Oral hygiene instruction and improve motivation would be extracted. A decision was made to keep those
towards dental treatment teeth that had a reasonable prognosis. The lower arch had
2. Probing depth measurements in sextants scoring 4 reasonable bone support and the periodontal treatment
3. Scale and polish followed by root planing focused on this area. The teeth in the upper arch had a
4. Removal of all upper teeth with the exception of the poor prognosis. However, the canines could be saved and
canines and the construction of an immediate replace- they would prevent bone resorption from the loads applied
ment denture by the lower natural teeth. This would prevent the forma-
5. RCT on upper canines tion of a flabby ridge where the tissue remained but where
6. Removal of crowns, convert canines to overdenture there was resorption of the underlying bone. The abut-
abutments and addition of artificial teeth to present ment teeth would also help with retention and stability of
denture the upper denture.
7. Review and monitor situation until new complete
denture made in 12 months’ time.
Outcome
The periodontal treatment was carried out and the patient
Discussion
made exceptional progress. The teeth were cleaned and
The periodontal condition of this patient was poor and this was followed by root planing of the lower quadrants.
there was a strong possibility that the majority of the teeth The removal of the upper teeth was undertaken as planned 209
Restorative Dentistry
Case 6 (a)
(a) (b)
(c) (d)
Fig. 13.18 Clinical photographs of Case 6 pre-treatment.
compromise gingival health. Some of the teeth were not maintenance visits. Consequently, his dentition had been
restorable and would require extraction, to be carried out neglected.There was fracture of an overdenture abutment,
early in the treatment plan. periapical pathology and deficient crown margins related
Therefore, the following treatment plan was made: to root caries. The treatment plan aimed to remove those
teeth that were not restorable and then to provide
1. Scale and polish and intensive oral hygiene instruction
preventative treatment. Very early on in the treatment, a
– this to be undertaken by a hygienist.The instructions
provisional denture design should be drawn up and this
to the hygienist should include particular emphasis on
would help with the subsequent restorative treatment. A
denture hygiene
provisional appliance should be placed to correct the
2. Extraction of UR3 and LL4
increased occlusal vertical dimension and to protect the
3. RCT LL2 (Fig. 13.20)
replacement crowns prior to the construction of the final
4. Restore LL23
denture. Then it will be possible to undertake the root
5. Draw up provisional removable partial denture design
canal treatment and the replacement of the crowns.
6. Provisional occlusal splint to increase the occlusal
Finally the dentures should be made and the patient
vertical dimension
placed on a strict maintenance regime.
7. Gold coping UR2
8. Replace porcelain-bonded crowns UL12, incorporating
rest seats in the cingulum area Outcome
9. Construction of upper and lower removable partial
In this case the treatment progressed without complication
dentures
according to the original plan that was made. Maintenance
10. Maintenance.
has been ongoing for 2 years and at the 24-month stage it
was noticed that wear of the occlusal surfaces of the acrylic
Discussion
teeth had occurred and a new denture was constructed.
This plan brought together all the specialities involved The periodontal condition and other restorative work has
within restorative dentistry. The patient had worn his remained stable and there has not been any new root
present denture for 5 years but had not been on regular caries diagnosed (Figs 13.21a–e).
212
13 / Integrated treatment planning
(a) (b)
(c) (d)
(e) (f)
Fig. 13.21 Case 6 post-treatment.
Case 7
CO. The patient complained of sensitivity to cold drinks
on several posterior teeth and additionally stated that she
Miss MM (27 years old) was aware that her anterior teeth were ‘chipping’ and
becoming shorter.
RFA. The patient attended, having complained that her
teeth were sensitive to hot and cold drinks at a meeting with HPC. The patient had experienced similar problems for
a psychologist at an eating disorders self-help group. The approximately 3 years but stated that the problem was
psychologist subsequently arranged a dental appointment. worsening on the right side of her mouth.
213
Restorative Dentistry
MH. The patient stated that she had been bulimic for 4 Teeth present (Fig. 13.22):
years and that she had previously vomited up to 15 times
87654321 12345678
per day. She also said that, now that she was attending the
7654321 1234567
self-help group, she was getting the habit under control
and that she now wished to have the appearance of her
BPE:
teeth improved and the sensitivity treated.
DH. She had been a regular attender in the past, when she 1 1 1
had received a number of amalgam restorations, but had 1 2 1
only received one course of treatment since she started
The standard of oral hygiene was fair with some plaque
suffering from bulimia. That treatment had involved the
and calculus deposits.
placement of three crowns in the upper left quadrant for
the treatment of sensitivity.
Conservative assessment
PH/SH. The patient brushed her teeth many times per
day, usually after vomiting. She rarely used floss. Her diet Full crown restorations were present at UL 654. Restora-
history was vague. tions of amalgam were present in many posterior teeth. In
many of these teeth, dentine was exposed occlusally and
Extraoral. There were no problems with the TMJs, no
amalgam restorations which were present stood proud of
facial asymmetry and no cervical lymphadenopathy.
the tooth surface (Fig. 13.23). Such features are typical of
Intraoral. The soft tissues were generally healthy. Plaque the patient suffering from bulimia. Dentine was exposed
deposits were noted on the buccal aspects of some upper on the palatal aspects of the upper anterior teeth, with the
posterior teeth. incisors being particularly affected. The incisal edges of
the upper anterior teeth were chipped, and in UL12 they
were translucent due to the loss of support for the incisal
enamel (Fig. 13.24). The mandibular incisor teeth also
exhibited tooth substance loss (TSL), with dentine being
exposed at the incisal edges of these teeth.
Many teeth contained restorations in amalgam. Many
required replacement because of tooth substance loss
around the restorations and because of the patient’s
complaint of sensitivity. The full crown restorations in the
maxillary left quadrant were of good fit. Caries was noted
in a number of mandibular posterior teeth.
(a)
Diagnosis
Diagnoses of erosive tooth substance loss and caries were
made.
Treatment plan
Treatment objectives were to counsel the patient in respect
of the causes of the erosive TSL, to cover the areas of
exposed dentine which were causing sensitivity, to treat
the caries, to improve oral hygiene and to improve the
appearance of the upper anterior teeth. Fig. 13.25 Preparation for full-coverage dentine-bonded crowns
It was decided that the caries would be treated by on UR45 and onlay at UR6.
placement of amalgam restorations. The TSL, which was
particularly severe at UR456 and LL54, would be treated
by placement of full coverage restorations, except at UR6
in which it was considered that an onlay-type restoration
would be satisfactory. Because of the erosive TSL, the
teeth to be crowned were of reduced crown height. It was
therefore considered that conventional crowns would be
likely to be poorly retained, so adhesive restorations were
indicated, i.e. dentine-bonded crowns.
The anterior teeth should also be crowned. Palatal
veneers in ceramic or composite could be provided. These
would effectively cover exposed areas of dentine but would
have no impact on the poor aesthetics about which the
patient had expressed concern. It was therefore decided
that minimal preparation full crown restorations should be
placed, i.e. dentine-bonded crowns. In these restorations,
there is no metal framework, so the preparation is less than Fig. 13.26 Restorations in UR46 at placement. 215
Restorative Dentistry
Fig. 13.27 Preparations for full-coverage dentine-bonded crowns Fig. 13.30 Crowns at UR12UL12 at placement.
at LL45.
Discussion
Patients are increasingly presenting with TSL, the causes
often being multifactorial, involving erosion and attrition.
A management priority must be removal of the cause, and
this will involve counselling the patient once the causative
factors have been identified. However, in cases of erosive
TSL when the patient is bulimic, counselling may be
difficult, as the patient may not, at the outset, admit to the
bulimic habit. In this respect, it has been considered that
Fig. 13.28 Restorations at LL45 at placement. bulimia or other gastic reflux habits may account for a
substantial proportion of cases presenting with severe TSL
in which the patient does not admit to dietary factors such
as excessive consumption of citrus drinks or fruits, or
carbonated beverages.
Treatment of patients suffering from bulimia may be
problematic, as these patients often suffer from other
problems such as drug or alcohol abuse. Accordingly,
there may be problems with attendance. These patients
may have poor self-esteem and poor body image. The
dentist may therefore play a real part in improving this.
There are problems related to the retention of restorations
in teeth affected by TSL, so the adhesive techniques,
which are available, may be indicated. However, there is
no rule which states that tooth wear must be treated by
tooth-coloured restorations, and so many of this patient’s
mandibular teeth, which were affected by TSL and caries,
Fig. 13.29 Minimal preparations for dentine-bonded crowns at were treated by placement of amalgam restorations in an
UR12UL12.
undergraduate student clinic. There are other problems
often associated with the treatment of teeth affected by
4. Provision of dentine-bonded crowns at LL54, UR45 TSL, namely the over-eruption of opposing teeth leaving
and a ceramic onlay at UR6 (Figs 13.25–13.28) reduced – or no – space for restorations. In such cases,
5. Provision of dentine-bonded crowns at UR12, UL12 the use of a Dahl appliance or the Dahl principle may be
216 (Figs 13.29 and 13.30). necessary. In this case, this did not present as a problem,
13 / Integrated treatment planning
(a) (b)
which meant that treatment could be carried out without C.O. The main complaint was a loose lower denture.
any change to the patient’s occlusion.
H.P.C. The patient had been rendered edentulous over
15 years ago. An immediate denture had been provided
Outcome with subsequent conventional sets over the years. The
patient has always found it difficult to cope successfully
The patient responded well to the efforts of the dental
with a lower denture and this has caused problems espe-
team. She stated that she ‘felt much better about herself’
cially during eating and speaking. She is rapidly becoming
and eventually reduced her bulimic habit and returned to
a recluse as she does not accept invitations to go out to
work. While this may not have been solely due to the
dinner with friends due to embarrassment caused by not
dental treatment that the patient received, the fact that
being able to eat properly. If the dentures are worn for
someone was prepared to care for her and treat her
a long period, i.e. a few hours, then the patient suffers
dentition – which also resulted in an aesthetic improve-
with ulcers.
ment – may have helped to improve her self-esteem.Those
of the patient’s teeth which have not received full coverage P.M.H. There was nothing relevant.
restorations are now checked 6-monthly for TSL. Caries
P.D.H. The patient has had four sets of dentures made
appears to be under control.
since the teeth were extracted but none of the lowers have
been successful. In contrast the patient has not experienced
any problems with wearing a complete upper denture.
Case 8 P.H./S.H. The patient uses dentural (hypochlorite based
cleaner) to soak the dentures at night time.
Mrs FW (63 years old) Extraoral. No abnormalities observed.
R.F.A. The patient was referred for an implant assessment. Intra oral. The soft tissues were healthy. 217
Restorative Dentistry
Denture-bearing areas
The upper edentulous ridge was well formed and the tissues
were healthy. There was a good vault to the palate. The
lower ridge was present and appeared healthy. However,
although there was a ridge present, it was poorly defined
compared to the upper ridge.
Prosthodontic assessment
The upper denture was both stable and retentive. In
contrast, the lower denture was not stable or retentive. It
was easily displaced by the soft tissues of the tongue and
the lips.
Fig. 13.32 A panoramic radiograph showing the position of two
Static/dynamic occlusion of artificial teeth endosseous implants in the anterior part of the mandible.
Diagnosis
A diagnosis was made of an unstable and unretentive
lower denture as a result of a poor anatomical form of the
lower denture-bearing area.
Treatment plan
This patient has had a long history of difficulties with
wearing a lower denture over a number of years. After a
joint consultation with the oral surgery team a decision Fig. 13.33 The second surgical stage revealing a healing
was made to provide an implant-retained lower over- abutment over one of the implant fixtures.
denture for the patient. Two implants were placed in the
anterior part of the lower mandible and these were left in
situ for 3 months. After this time a small surgical proce-
dure was undertaken to expose the underlying fixtures
and two abutments with studs were placed into position
(Figures 13.32–13.36).
The existing denture was adjusted in the area where the
studs were positioned so that the patient could wear the
old dentures during the construction of the new dentures.
The major task when providing the new lower denture is
the provision of gold clips which are incorporated into the
denture. These precision attachments are held in the
acrylic baseplate and attach onto the studs when the
denture is placed into the mouth. The implant manu-
facturer will supply transfer impression copings which may
be picked up at the final impression stage.This enables the
technician to construct a replica of the studs and process
the clips into the acrylic baseplate. The making of the new
prosthesis follows traditional stages of complete denture Fig. 13.34 The one-piece stud abutments which attach to the
218 construction and at the final process stage the gold clips implant fixture.
13 / Integrated treatment planning
Discussion
This is a simple overview of one particular method of
using implants to secure a loose lower denture in place.
Other methods of attaching the denture to the underlying
implants include the use of a linked bar with clips in the
denture or the use of magnets in the baseplate adhering
onto keepers held on the fixtures. This form of treatment
for the edentulous patient is becoming a popular method
of improving the quality of life of those people who have
found wearing of complete dentures to be unsatisfactory. Fig. 13.39 The finished acrylic baseplate with the two clip
The reader is directed to the further reading section at the attachments in position. 219
Restorative Dentistry
220
References and suggested
further reading
Caries Materials
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caries lesions. Dental Update 32:402–413. biomaterials. Kluwer Academic Press, Boston.
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should we do about it? Quintessence International 8th edn. Blackwell Munksgaard, Oxford.
29:668–762. • Roeters J J, Shortall A C, Opdam N J 2005 Can a single
• Kidd E A 2005 Essentials of dental caries. The disease and composite resin serve all purposes? British Dental Journal
its management, 3rd edn. Oxford University Press, Oxford. 199:73–79.
• Kidd E A 2004 How ‘clean’ must a cavity be before
restoration? Caries Research 38:305–313. Occlusion
• Mount G J, Hume W R 2005 Preservation and restoration of • Klineberg I, Jagger R 2004 Occlusion and clinical practice.
tooth structure, 2nd edn. Knowledge Books and Software, Elsevier Books, Edinburgh.
Queensland.
Osseointegrated implants
Complete dentures • Feine J S, Carlsson G E 2005 Implant overdentures: the
• Basker R M, Davenport J C 2002 Prosthetic treatment of standard of care for edentulous patients. Quintessence, UK.
the edentulous patient, 4th edn. Blackwell Munksgaard, • Hobkirk J A, Watson R, Searson L 2003 Introducing dental
Oxford. implants. Elsevier Books, Edinburgh.
• Crawford R W, Walmsley A D 2005 A review of
Overdentures
prosthodontic management of fibrous ridges. British Dental
Journal 199:715–719. • Basker R M, Harrison A, Ralph J P et al 1993 Overdentures
• Gahan M J, Walmsley A D 2005 The neutral zone in general dental practice, 3rd edn. British Dental Journal
impression revisited. British Dental Journal 198:269–272. Books, London.
• Watt D M, MacGregor A R 1986 Designing complete • Crum R J, Rooney J R 1978 Alveolar bone loss in
dentures, 2nd edn. John Wright, Bristol. overdentures: A five year study. Journal of Prosthetic
Dentistry 40:610–613.
Core build-up and veneers
Periodontology
• Lynch C D, McConnell R J 2002. The cracked tooth
syndrome. Journal of the Canadian Dental Association • Drisko C H 2000 Nonsurgical periodontal therapy.
68:470–475. Periodontology 25:77–88.
• Summit J B, Robbins J W, Hilton T J et al 2007 • Lindhe J, Karring T, Lang N 2003 Clinical periodontology
Fundamentals of operative dentistry. Quintessence and implant dentistry, 4th edn. Blackwell Publishing,
Publishing, Chicago. Oxford.
• Tonetti M S 2000 Advances in periodontology.
Endodontics Primary Dental Care 7:149–152.
• Cohen S, Burns R 2002 Pathways of the pulp, 8th edn.
Prevalence studies on tooth wear
Mosby, St. Louis.
• Lumley P J, Tomson P, Adams N 2006 Practical clinical • Bartlett D W, Coward P Y, Nikkah C et al 1998
endodontics (dental update). Churchill Livingstone, The prevalence of tooth wear in a cluster sample of
Edinburgh. adolescent schoolchildren and its relationship with
• Ørstavik D, Pitt Ford T R 1998 Essential endodontology, potential explanatory factors. British Dental Journal
Blackwell Science, Oxford. 184:125–129.
• Walton R E, Torabinejad M 2001 Principles and practice of • Chadwick B L, White D A, Morris A J et al 2006
endodontics, 3rd edn. Elsevier Health, Amsterdam. Non-carious tooth conditions in children in the UK, 2003.
British Dental Journal 200:379–384.
Fixed prosthodontics • Hind K, Gregory J R 1994 National diet and nutrition
• Rosenstiel S F, Land M F, Fujimoto J 2006 Contemporary survey; children to 4.5 years, volume 2: Report of the dental
fixed prosthodontics, 4th edn. Elsevier Books, St Louis. survey. Office of Population Census and Surveys. HMSO,
• Smith B G N, Howe L G 2006 Planning and making crowns London.
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Indirect tooth-coloured restorations backgrounds. ASDC Journal of Dentistry for Children
• Dietschi D, Spreafico R 1997 Adhesive metal-free 61:263–266.
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221
References and suggested further reading
222
Index
R Restorations—cont’d Saliva
replacement, 57, 71–72 caries and, 59, 63–64, 75
Radiographic examination, 21 simple, 76–87, 197 erosion and, 68–69
caries diagnosis, 61 Restorative dentists, role of, 1 tooth discoloration and, 71
root canal length, 99 Retention Salivary pellicle, 36
tooth substance loss, 138 bridges, 153, 154, 155, 155, 159, 159, Salt water rinses, 36
RaPiD, 175, 175 163 Scaling, 36
Rapidly progressive periodontitis, 28, 28, overdentures, 179–180, 179, 180, 194, instruments for, 37–42, 37–40
35 210, 218–219 root debridement and, 36
Reaming movement, 93 partial dentures, 166, 171–172, 172, Sealants
Reciprocating handpieces, root canal 174, 174, 175 fissure, 75
debridement, 93–94, 94 Retruded arc of closure, 51 root canal retreatment, 112
Reciprocation, partial dentures, 166, Retruded contact position (RCP), 51, root canal treatment, 102, 103–104,
172, 172 53, 140, 148 106, 107, 112
Record-keeping, 13, 21, 22 Retruded position (RP), 51, 55 Sebaceous glands, cheek, 3
Refractory periodontitis, 28–29, 29, 35 Ridge, 6 Sensitivity, hydrodynamic theory, 8
Registration, complete dentures, Ridge of Passavant, 6 Sensory feedback, overdentures and,
188–189, 190, 190 Rochette bridges, 160, 160 176
Removable partial dentures (RPDs), Root canal anatomy, 7–8, 97–98, 205 Sensory nerves, dental pulp, 8
146, 147, 162–175, 195 Root canal investigations, 21 Shared guidance, occlusion, 53
case study, 207 Root canal retreatment, 107, 108–112, Sharpey’s fibres, 10, 11
dental surveying, 164–166 108–113 Shortened dental arch, 146, 147, 147
design, 166–175 Root canal treatment, 92–113 Sickle scalers, 39, 39, 42
bracing, 166, 172, 173 assessment, 107 Silane coupling agents, 79
computer-aided, 175, 175 bridges and, 154 Silicoater technique, 161
connectors, 166, 172–174, 173–174 canal preparation, 96–102 Silicone index, 69, 139, 139, 140
indirect retention, 166, 174, 174, case studies, 203–206, 207 Silver amalgam, 116, 117
175 chemomechanical debridement, 92–96 Silver point root canal fillings, 102, 110,
reciprocation, 166, 172, 172 crown restorations and, 118, 119–121, 111, 112
retention, 166 171–172, 172 119, 120–121 Simple restorations, 76–87, 197, 198
saddles, 166, 167, 168–169, 170, 171 integrated treatment planning, Sinuses, 21
support, 166, 167–171, 167–171 198–199 ‘Slot’ preparation restorations, 86
visits required for, 175, 176 management of failed, 107–113 Smear layer removal, 95
design sheet, 162, 164, 164 obturation, 102–107 Smith and Knight index, 19, 19, 69
rest seat preparation, 162 one-visit, 102 Smoking, 17
tooth contour modification, 164 Root cleaning, 36 acute necrotising ulcerative gingivitis,
Removable prosthetics see also Root debridement 25, 25, 33
assessment, 20 Root debridement, 36, 42–43 tooth replacement and, 148
case studies, 207, 210–213, 216–220 acute periodontal abscesses, 36 Social history-taking, 16–17, 136–137,
complete dentures, 184–191 analgesia, 37, 43 148, 186
factors in choosing, 145–148 HIV-associated periodontitis, 36 Socketed immediate dentures, 183
immediate dentures, 181–184 instruments for, 37–39, 40, 43, 43 Sodium hypochlorite, 95–96
integrated treatment planning, 198, refractory periodontitis, 29, 35 Soft palate, 5–6
199 scaling and, 36 Sonic units
occlusion, 51, 53, 54, 54, 55, 55 Root filling materials, 102–106 root canal debridement, 94
overdentures, 175–181, 194, 196, 210, root canal retreatment, 110–112 scaling, 40, 41, 42
218–220 Root fractures, 67, 67, 106, 107, 110 Spongiform encephalopathies, 16
partial dentures, 146, 147, 162–175, Root planing, 42–43 Spreaders
195, 207 see also Root debridement root canal obturation, 103, 104
Reorganisational care, 55 Root surface caries, 60, 63 root canal retreatment, 112
Resin-bonded bridges, 157–162, 163, 195 Root surface defects, refractory Spring cantilever bridges, 151–152, 151,
Resin composites and restorations, 76, periodontitis, 29 158
78–80, 78–79, 81, 83–85, 83, 84 Root surface deposits Stains, 70–71, 71
bridges, 157–162, 195 non-surgical management, 36–43 caused by restorative materials, 71, 72
complex, 117, 117, 126 see also Root debridement removal, 36, 40–42, 70, 71
thermal sensitivity, 85 refractory periodontitis, 29 Stephan curves, plaque pH, 59, 59
tooth-coloured inlays, 126, 128 Rotary nickel titanium (NiTi) Streptococci, 59, 63–64
Resin-modified glass ionomers instrumentation, 94–95, 94–95, Stress breakers, partial dentures, 171
(RMGIs), 81, 82, 82, 117–118 101–102, 110, 111 Studs, overdenture retention, 179, 179,
Respiratory conditions, 16, 17 RPI system, 170, 170 194, 194, 196, 218–219
Restorations Rubber dams, 92, 92, 97, 107 Study casts see Casts
causing tooth fractures, 66, 77 Rugae, palatal, 5, 5 Subgingival antimicrobials, 45–46
complex, 115–134 Subgingival calculus, removal, 36, 36,
see also Crown restorations S 39–40, 43
conservative assessment, 18, 20 see also Subgingival scaling
integrated treatment planning, 197, Saddles, removable partial dentures, Subgingival curettage, 40
228 198–199 166, 167, 168–169, 170, 171 Subgingival irrigation, 35, 45–46
Index
229