Decision-Making in Operative Dentistry

Foreword

It is widely accepted that more that 60 per cent of a general dental practitioner’s time is spent practising operative dentistry, predominantly the replacement of restorations. Central to success in this major element of everyday practice is effective decision-making. Realising that goal is difficult given limitations in many of the existing diagnostic systems and techniques – and the lack of consensus in respect of criteria for certain forms of operative intervention. Moreover, the existing literature gives mixed messages – for example, in relation to the use of liners, bases and sealers.

In addressing questions frequently posed by practitioners, Decision-Making in Operative Dentistry – Volume 3 of the Quintessentials for General Practitioners Series – is highly relevant to the modern practice of dentistry. For practitioners not yet introduced to the concepts of minimal intervention, the repair and refurbishment of restorations, and conservative techniques for the management of tooth wear, this book will be a revelation. For colleagues familiar with such concepts, Decision-Making in Operative Dentistry will be an invaluable guide to the when, where and how of the modern patient-centred approach to the conservation of teeth. Written in the succinct, easy-to-read style that characterises the Quintessentials for General Dental Practitioners Series, this book will not fail to give the busy practitioner new knowledge and insight that can be immediately applied to the benefit of patients. For practitioners who think that operative dentistry has not really changed since they were a student, this book is indispensable reading.

Nairn Wilson

Editor-in-Chief

Preface

This book does not seek to provide the reader with comprehensive coverage of the subject of operative dentistry. There are already several excellent textbooks available that have addressed the subject in depth, particularly from the undergraduate’s perspective.

This book is about the practice of contemporary operative dentistry in primary dental care. Its principal aim is to assist clinical decision-making in the dental surgery and provide answers to the questions practitioners frequently ask. As such, the approach to the subject is very different and somewhat novel.

Preservative operative dentistry is the philosophy on which this book is based. The continued use of amalgam, particularly for initial lesion management, does not sit well with this philosophy. Amalgam has, however, been included in this edition to ensure comprehensive coverage. I suspect that future editions will not cover or support the continued use of amalgam.

The classification of lesions of caries has changed in recent years. Accordingly, I have not used Black’s classification, preferring to classify lesions as occlusal, proximal and cervical. Similarly, the FDI system of tooth notation has been used. On a final note, this book considers the restoration of the adult dentition with direct restorative materials and techniques. Readers will be aware that operative dentistry includes the provision of single-unit indirect restorations, which is outside the remit of this publication.

On reading this book the reader will be able to:

diagnose caries more effectively, especially in its early stages

intervene appropriately and only when absolutely necessary

prepare teeth minimally and effectively

select the correct restorative material

understand modern pulp protection regimes

select restorations suitable for repair and refurbishment procedures

identify and treat non-carious tooth tissue loss.

Paul A Brunton

Acknowledgements

The author would like to thank Drs Andrew Bristow, Paul McCabe, Leean Morrow, David Simpkins, Chris Sweet, Ian Wood and Professor David Watts for reviewing the entire manuscript and providing valuable feedback.

The author is also indebted to the following individuals and publishers who have generously provided illustrations which have made the publication of this book possible. Figs 1-6–1-9: Dr Denise Cortes, Gama Filho University, Brazil; Figs 1-5 and 1-16: Dr Roger Ellwood; Figs 1-11 and 1-12: Dr Viv Rushton; Fig 1-15: KaVo (UK) Ltd.; Fig 4-5: Professor NairnWilson; Figs 4-6–4-13: reproduced with kind permission of Independent Dentistry; Figs 6-2–6-6, 6-9–6-12, 6-13–6-18: reproduced with kind permission of Quintessenz Verlag, Berlin; Figs 7-2–7-4: Ms Leean Morrow; and Figs 7-6, 7-8 and 7-9: reproduced with kind permission of FDI World Press Ltd.

Chapter 1

Clinical Diagnosis of Dental Caries. Is it Caries?

Aim

With changing patterns of disease experience the diagnosis of caries, particularly in its early stages, continues to be difficult for clinicians. The aim of this chapter is to improve understanding of modern methods of caries diagnosis.

Outcome

Practitioners will be familiar with modern methods of detecting dental caries and their relevance to contemporary dental practice.

Introduction

The pattern of dental caries has changed in recent years, with smooth surface lesions becoming less common and new lesions more likely to develop in pits and fissures. It is arguably easier to diagnose early caries on smooth surfaces (with the exception of proximal surfaces) than in pits and fissures, particularly when occult occlusal caries is present. In this condition the tooth can appear sound when examined visually but on radiographic examination there is extensive caries affecting the dentine (Fig 1-1).

Fig 1-1 Radiograph showing caries as follows: mesial 16, distal and mesial 15, distal 45, mesial and distal 46 and mesial 47.

Diagnostic Tests

With all diagnostic tests there is potential for operator error. For example, four outcomes are possible when a diagnostic test is applied to detect caries. These are as follows:

True positive

This occurs when caries is present and the test correctly identifies this. A good diagnostic test will have a high percentage of true positive outcomes.

False positive

A false positive result occurs when a diagnostic test incorrectly identifies caries when caries is not present.

True negative

This outcome is the opposite of a true positive result. It occurs when the test correctly identifies an individual as caries free and they are, in fact, free of the condition.

False negative

If a patient has caries and the test incorrectly deems them to be caries free then the outcome is defined as false negative.

These four possible outcomes of a diagnostic test are summarised in Fig 1-2.

Fig 1-2 Diagrammatic representation of diagnostic test outcomes.

Sensitivity and Specificity

Sensitivity and specificity are both measures of how accurate a diagnostic test is in terms of its ability correctly to identify individuals as diseased and non-diseased. Sensitivity is defined as the proportion of true positives that are correctly identified. It is calculated as follows (true negative = a, false negative = b, false positive = c, true positive = d):

The numbers of true positives and false negatives are related numerically; hence the proportion of true positive results for a diagnostic test (sensitivity) is 1 minus the false negative rate.

Specificity is the proportion of correctly identified true negative results and this is 1 minus the false positive rate. It is calculated as follows:

A good diagnostic test would have both high specificity and high sensitivity, which means the number of times the test is likely to give an incorrect result is low. In practice, as the level of either sensitivity or specificity rises, the other falls, so a balance must be struck.

The sensitivity and specificity of diagnostic tests commonly used to detect dental caries are shown in Table 1-1.

Visual Examination

Visual examination of a tooth is the most widely used method of diagnosing dental caries. This method is, however, incredibly