Removable Partial Dentures E-Book

Nicholas J. A. Jepson

• Herausgeber: Quintessence Publishing Co. Ltd.
• Kategorie: Fachliteratur
• Serie: QuintEssentials of Dental Practice
• Sprache: Englisch

Seitenzahl: 161

Veröffentlichungsjahr: 2019

Beschreibung

If partial dentures are worth making, then they are worth making well. This book presents a review of demographic changes in the partially dentate population, the increasing availability of alternative treatments, and evidence for the long-term effectiveness of partial dentures. In addition, it provides evidence-based guidelines that practitioners can apply to the design, preparation, completion, and maintenance of removable partial dentures in their everyday clinical practice.

Leseprobe

Quintessentials of Dental Practice – 18Prosthodontics – 3

Removable Partial Dentures

Author:

Nicholas J A Jepson

Editors:

Nairn H F Wilson

P Finbarr Allen

Quintessence Publishing Co. Ltd.

London, Berlin, Chicago, Copenhagen, Paris, Milan, Barcelona, Istanbul, São Paulo, Tokyo, New Delhi, Moscow, Prague, Warsaw

British Library Cataloguing in Publication Data

Jepson, N. J. A. Removable partial dentures. - (Quintessentials of dental practice; 18. Prosthodontics; 3) 1. Partial dentures, removable I. Title II. Wilson, Nairn H. F. III. Allen, P. Finbarr 617.6′92

ISBN 1850973180

Copyright © 2004 Quintessence Publishing Co. Ltd., London

All rights reserved. This book or any part thereof may not be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, or otherwise, without the written permission of the publisher.

ISBN 1-85097-318-0

Dedicated to my family and my patients.

Table of Contents

Title Page

Copyright Page

Foreword

Preface

Acknowledgements

Chapter 1 Partial Denture Provision

Aim

Outcome

The Partially Dentate Population

The Effectiveness of Partial Denture Provision

Appearance

Masticatory function

Maintaining occlusal stability

Consequences of Partial Denture Use

Patient acceptance

Long-term effects

Caries and periodontal disease

Plaque and partial dentures

Changes to the alveolar process

Key Points

References

Further Reading

Chapter 2 Indications for Partial Dentures

Aim

Outcome

Treatment Options

Reasons Not to Provide Partial Dentures

A functionally oriented approach

When to Use Partial Dentures

Number and distribution of missing teeth

Status of potential abutment teeth

Soft tissue loss

Anterior tooth spacing

Restoration of occlusal face height

Patient preference and cost

An interim replacement for missing teeth

Key Points

Further Reading

Chapter 3 Basic Principles of Partial Denture Design

Aim

Outcome

Classification of Partial Dentures

Design and Stability in Function

Design and the Prevention of Harmful Effects

Partial Denture Design: Current Principles

Key Points

Chapter 4 Partial Denture Design: Saddles, Rests and Retainers

Aim

Outcome

Saddles

Saddle–abutment relationship

Extension of the fitting surface

Design of the occlusal surface

Material of the fitting surface

Rests

Rests in posterior teeth – occlusal rests

Rests in anterior teeth

Cingulum rests

Incisal rests

Retainers

Direct retainers

Effective clasp assemblies

Factors affecting clasp retention

The number of clasps required

Support and retention of free-end saddle dentures

Differential support

Rotation

Clasp design

Rest position

Indirect retainers

Key Points

Chapter 5 Partial Denture Design: Connectors

Aim

Outcome

Introduction

Major Connectors

General principles of design

Maxillary major connectors

Palatal plates

Anterior and posterior bars (ring connector)

Horse-shoe connector

Mandibular major connectors

Lingual bar

Sublingual bar

Dental bar

Lingual plate

Buccal bar

Kennedy bar (continuous clasp)

Minor Connectors

Key Points

Chapter 6 Surveying

Aim

Outcome

Introduction

Surveying

Retention

Guide surfaces (guiding planes)

Aesthetics

Dead spaces and interferences

Dead spaces

Interferences

Practical Surveying

Key Points

Chapter 7 Transitional Partial Dentures

Aim

Outcome

Introduction

Design of Transitional Dentures

Indications for Transitional Partial Dentures

Immediate partial dentures

Prolonged restorative treatment

Age

Examples of Commonly Used Transitional Dentures

Spoon denture

Transitional partial denture with metal rests and clasps

The Every denture

The Transition to Edentulousness

Trainer partial dentures

Key Points

Chapter 8 Clinical Guide I: Gathering the Information

Aim

Outcome

Introduction

Examination and Preliminary Impressions

Initial evaluation

Case history

Examination

Articulated study casts

Preliminary (study cast) impressions

Further investigations

Common errors

Preliminary Registration and Denture Design

Preliminary registration

Anterior try-in

Common errors

Definitive Treatment Plan

Key Points

Chapter 9 Clinical Guide II: Establishing the Denture Design

Aim

Outcome

Introduction

Step 1

Comments

Suggestion

Step 2

Comment

Suggestion

Step 3

Comments

Suggestions

Step 4

Comments

Suggestions

Step 5

Comment

Step 6

Comment

Suggestions

Step 7

Comments

Suggestions

Step 8

Comment

Suggestion

Common errors at this stage

Key Points

Chapter 10 Clinical Guide III: Preparation of the Mouth for Partial Dentures

Aim

Outcome

Introduction

Tooth Preparation

Guide surfaces

Lowering survey lines

Embrasure widening

Rest seat preparation

Occlusal rests

Cingulum rests

Incisal rests

Creation of clasp undercut

Common errors during tooth preparation

Crowning Abutment Teeth

Construction of crowns to fit an existing partial denture

Key Points

Chapter 11 Clinical Guide IV: Completing and Maintaining the Partial Denture

Aim

Outcome

Working Impressions

Common errors

Try-in of the Metal Framework

Common errors

Altered Cast Impression (Lower Free-end Saddle Dentures)

Common errors

Definitive Registration

Partial Denture Try-in

Common errors

Partial Denture Insert

Common errors

Review and Maintenance

Key Points

Foreword

Success in partial denture prosthodontics – in addition to being a real practice-builder – can be very satisfying. The art and science of partial denture prosthodontics may, however, be viewed as complex and challenging. But, as with most things in dentistry, and as is emphasised in this most welcome addition to the Quintessentials of Dental Practice Series, success in the provision of partial dentures is dependent on the adherence to a number of inescapable, underpinning principles: good diagnosis, including an understanding of the patient’s needs and expectations, knowledge and understanding of the capabilities of existing materials and techniques, careful planning and attention to detail. Equally important is the need to control and treat active oral disease prior to embarking on the replacement of missing teeth – a principle which the author of this carefully crafted, succinct text rightfully places great importance on.

Turning to practical matters, this book provides the practitioner with evidence-based guidelines directly applicable to everyday clinical practice. Of particular note is the sound, easy-to-follow and refreshingly pragmatic approach to partial denture design – an element of partial denture provision which must be undertaken by the practitioner if the completed dentures are to be acceptable and pleasing to the patient, let alone perform well in clinical service. If you suspect that many of your partial dentures – in particular, your lower free-end saddle – dentures spend most of their time in a jar, or worse have been lost at the back of some bathroom cabinet or other domestic black hole for items which appeared to be a good idea, but proved to be of little, if any, practical value, then you should read this book. If partial dentures are worth making, then they are worth making well – the thrust of this insightful book.

As you would expect of a volume in the Quintessentials of Dental Practice Series, this book is extensively illustrated with high-quality images and produced to an excellent standard. Few, if any, other books on partial dentures provides so much information in a text which may take only an evening or two to read and digest. Your partially dentate patients would be very pleased to hear that this book has formed part of your Continuing Professional Development.

Nairn Wilson Editor-in-Chief

Preface

A partial denture may be defined as a removable prosthesis that replaces a missing tooth or teeth and associated supporting tissues in an arch where some natural teeth remain. It is one of the means of restoring the dental appearance and function for patients with missing teeth and, where such a need exists, there is strong evidence to support their successful use in the long-term.

In terms of materials and techniques very little has changed in recent years in the clinical provision of partial dentures. What has changed significantly is the context of this provision and our understanding of its effects. Important and continuing demographic changes of the partially dentate population, the increasing availability of alternative treatments and, above all, a substantial and growing evidence base for the long-term effectiveness of partial dentures are now significant influences on their use. This book presents a review of these influences and, based on evidence, a systematic and effective approach to removable partial denture provision.

Having Read This Book

It is hoped that after reading this book the reader will:

Recognise the demographic changes to the partially dentate population, and appreciate the effectiveness of partial dentures and the consequences of their use.

Understand the clinical and patient-related factors that indicate the use of partial dentures and recognise the need to base the provision of partial dentures on perceived aesthetic and functional needs of the patient.

Recognise that not all missing teeth need to be replaced and be aware of the concept of functionally oriented treatment planning for the partially dentate.

Understand the basic principles of partial denture design and the application of these principles to the design of the several partial denture components.

Understand the procedure of cast surveying and how this may be applied to the process of a simple and practical system of design for effective partial dentures.

Recognise that the design of partial dentures is the responsibility of the dental practitioner.

Be aware of the clinical techniques and materials used in the construction of partial dentures.

Understand the indications for and types of transitional partial dentures.

Nicholas J A Jepson

Acknowledgements

My thanks are due to Mr Dean Barker, Professor Bengt Öwall, Mr David Smith, and Mr Richard Tones for permission to use some of their photographs as illustrations in the text. I must also acknowledge the role played by my many past and present colleagues, patients and students in forming my views on treatment of the partially dentate in general and the use of partial dentures in particular.

Chapter 1

Partial Denture Provision

Aim

In industrialised countries, as the proportion of adults retaining some of their teeth into old age increases, so will the likely need for prosthetic intervention. This chapter aims to provide an overview of the need and demand for partial dentures to restore partially dentate adults.

Outcome

After reading this chapter the practitioner should be aware of the effectiveness and consequences of partial denture use.

The Partially Dentate Population

Evidence from various national dental health surveys in developed countries clearly indicates that the proportion of people with no teeth at all will continue to decline and that more people will retain some of their own teeth into old age. The results of the 1998 national dental health survey in the UK indicate that 87% of all adults had some natural teeth but that this proportion was strongly influenced by age. The mean number of missing teeth by age group for a number of developed countries is shown in Fig 1-1 using data from the WHO Collaborating Centre, Sweden (2003). Common trends are that significant tooth loss only becomes apparent after 45 years of age and that the number of missing teeth increases with age. The percentage of people ≥45 years of age provided with partial dentures differs between countries, a variation that reflects both differing public and professional attitudes to partial denture use and healthcare systems, but can reach levels of 20–30%. Where provision of partial dentures is a commonly used treatment option for the partially dentate, the principal deciding factor as to whether or not a partial denture is used appears to be the number of remaining natural teeth. Results of the 1998 UK Dental Health Survey clearly indicate that there is a cut-off point at 21–24 teeth and people with 21 or more teeth are unlikely to have removable partial dentures (Fig 1-2). This supports the important concept of a “functional dentition” which allows the patient sufficient function and comfort without the need for tooth replacements.

Fig 1-1 The mean number of missing teeth by age group (data from WHO Collaborating Centre, Malmö, Sweden 2003).

Fig 1-2 The proportion of partially dentate adults with removable partial dentures by number of natural teeth (Adult Dental Health Survey, Oral Health in the United Kingdom 1998).

The number of teeth that people retain has also increased. In the UK in 1998, over 72% of adults had 21 or more teeth although this figure reduced with age such that only 10% of people aged ≥75 years had 21 or more teeth. Projections for 2018 suggest that 90% of 16-74 year olds in the UK will have a natural dentition of 21 or more teeth though this proportion will again reduce with age. Such projections need to be seen in the context of increasing life span in industrialised countries with an increasing percentage of populations ≥65 years old. In the UK, for example, the number of adults over the age of 65 years is expected to rise by 2.7 million by 2021.

Increased tooth retention reflects the development of more positive attitudes to dental health and improved access to dental care. Adults increasingly wish to retain their natural teeth and are prepared to accept treatment recommended by their dentists to save their teeth. There is good evidence that dental attendance improves the possibility of retaining at least some teeth over the course of a lifetime. Increasingly, adults find the prospect of complete dentures unacceptable though, interestingly, such attitudes do not seem to apply to the use of partial dentures. The future then is one of increasing numbers of older partially dentate adults who may require partial dentures to replace missing teeth.

Projections based on data from national surveys have been used to estimate the future treatment need for the partially dentate. These estimates point to an increased need for both fixed and removable prosthesis. In the USA the projected total need for fixed and removable prosthesis is put at 115% of current provision by the year 2020. Partial dentures are the simplest, cheapest and by far the most common method of replacing missing teeth. In the UK approximately 30% of all middle aged and elderly adults have been provided with partial dentures. There is, however, an increasing acceptance of the use of fixed prosthesis by elderly patients and a growing recognition that implant-supported prosthesis offer a viable and, perhaps, more effective long-term treatment alternative for the partially dentate. Socio-economic factors would suggest, however, that the more frequent use of partial dentures will remain the situation for the foreseeable future. This together with the evident population trends would suggest that the need for partial dentures in developed countries is unlikely to decrease in the future and will probably remain relatively stable.

The Effectiveness of Partial Denture Provision

For the very large majority of cases, partial dentures are provided to improve appearance by restoring visible spaces resulting from the loss of typically anterior teeth and to improve function by restoring missing posterior, usually molar, teeth. In addition, the use of partial dentures is often advocated to maintain occlusal stability. This section will review the effectiveness of partial denture use in these circumstances.

Appearance

The improved appearance gained by the replacement of missing anterior teeth really needs no amplification (Fig 1-3). It is probably the main reason patients request partial dentures and, perhaps, continue to wear them but this is not inevitably the case. There is good evidence to suggest that the dentist’s and patient’s view of what is or is not a satisfactory appearance can differ markedly (Fig 1-4). The key factor is, of course, the patient’s opinion and this is strongly linked to what they perceive is an acceptable appearance in their social environment, a concept of social ease and acceptability well described by social scientists as “passing”. The age of the patient does seem to influence the importance attached to appearance. For younger patients, the loss of visible teeth is likely to be unacceptable and a powerful driving force to seek treatment, yet many elderly patients can find the presence of visible spaces resulting, for example, from the loss of first premolar teeth quite acceptable (Fig 1-5). As age increases there appears to be a greater focus on the need for acceptable function rather than appearance.

Fig 1-3 The presence of visible spaces because of missing anterior teeth is likely to be the main factor motivating this patient to seek treatment to replace them.

Fig 1-4 Somewhat surprisingly, the patient was insistent that the missing UL2 should not be replaced.

Fig 1-5 Many elderly patients find the presence of visible spaces quite acceptable.

Masticatory function

The classic description of the possible effects of a reducing number of natural teeth on masticatory function is shown in Fig 1-6. Tooth loss, in particular that of posterior teeth, results in difficulty chewing and biting food – that is a limitation of masticatory function. This in turn leads to changes in food choices, an impaired dietary intake that may be associated with nutritional deficiency. Replacement of missing teeth restores masticatory function and allows the patient more dietary freedom and the possibility to improve dietary intake.

Fig 1-6 The possible effects of a reducing number of natural teeth on masticatory function.

It was for many years a basic assumption that the progressive loss of posterior teeth would reduce chewing efficiency to the extent that problems of digestion would ensue. Indeed, there is evidence to suggest that as teeth are lost so objective measures of masticatory performance deteriorate. However, many patients with large numbers of missing posterior teeth have little or no complaint about their ability to chew food. They have no perceived functional limitation and, indeed, the poor correlation between objective and subjective assessments of masticatory function is a common research finding. Recent research suggests that patients can masticate adequately without molars and even second premolars, the assumption being that they compensate for a poor occlusion by swallowing larger particles of food rather than chewing for longer. The factor determining whether a patient perceives a limitation of masticatory function appears to be the number of pairs of occluding posterior teeth. Evidence suggests that unless the patient has fewer than three occluding pairs of posterior teeth there is no socio-functional benefit to be gained from replacing missing molar teeth in shortened dental arches. Assuming no loss of anterior teeth, this equates to a “functional threshold” of 21 or more teeth with three to five pairs of occluding posterior teeth – the “functional dentition” referred to earlier in the chapter.

The relationship between limitation of masticatory function resulting from tooth loss and impaired dietary intake has been established but much less clearly for the partially dentate than it has been for the edentulous. The indications are that the number and distribution of teeth are strongly associated with dietary intake. For example, the probability of achieving the recommended daily intake of a number of fruit and vegetables and that the measured intake of dietary fibre and vitamin C appears to fall with reducing numbers of pairs of occluding posterior teeth.

Although an improved masticatory function following the replacement of missing posterior teeth should allow more dietary freedom, there is no evidence that an improved dietary intake will be achieved unless treatment is accompanied by dietary advice. Clearly dietary habits do not simply reflect masticatory function. Other lifestyle and socio-economic factors are important influences and may, indeed, be associated with the loss of teeth in the first place. Given that the evidence for the effects of tooth loss on masticatory function and dietary intake is drawn almost exclusively from the developed countries, such findings are perhaps unsurprising. The less challenging nature of diets in industrialised societies means that nutrition and survival are no longer questions of masticatory function.

Maintaining occlusal stability