Protocols for Predictable Aesthetic Dental Restorations Protocols for Predictable Aesthetic Dental Restorations Irfan Ahmad BDS, The Ridgeway Dental Surgery, Middlesex, UK Active member European Academy of Esthetic Dentistry © 2006 I. Ahmad Blackwell Munksgaard, a Blackwell Publishing Company, Editorial Offices: Blackwell Publishing Ltd, 9600 Garsington Road, Oxford OX4 2DQ, UK Tel:+44 (0)1865 776868 Blackwell Publishing Professional, 2121 State Avenue, Ames, Iowa 50014-8300, USA Tel:+1 515 292 0140 Blackwell Publishing Asia, 550 Swanston Street, Carlton, Victoria 3053, Australia Tel:+61 (0)3 8359 1011 The right of the Author to be identified as the Author of this Work has been asserted in accordance with the Copyright, Designs and Patents Act 1988. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher. First published 2006 by Blackwell Munksgaard ISBN-13: 978-14051-1820-0 ISBN-10: 1-4051-1820-2 Library of Congress Cataloging-in-Publication Data Ahmad, Irfan, BDS. Protocols for predictable aesthetic dental restorations / Irfan Ahmad. p. cm. Includes bibliographical references and index. ISBN-13: 978-1-4051-1820-0 (pbk. : alk. paper) ISBN-10: 1-4051-1820-2 (pbk. : alk. paper) 1. Dentistry–Aesthetic aspects. 2. Prosthodontics. I. Title. [DNLM: 1. Esthetics, Dental. 2. Dental Restoration, Permanent. 3. Dental Restoration, Temporary. WU 100 A286p 2006] RK54.A46 2006 617.6′9–dc22 2005024528 A catalogue record for this title is available from the British Library Set in 10 on 12pt Sabon by SNP Best-set Typesetter Ltd., Hong Kong Printed and bound in Spain by GraphyCems, Navarra The publisher’s policy is to use permanent paper from mills that operate a sustainable forestry policy, and which has been manufactured from pulp processed using acid-free and elementary chlorine-free practices. Furthermore, the publisher ensures that the text paper and cover board used have met acceptable environmental accreditation standards. For further information on Blackwell Publishing, visit our website: www.dentistry.blackwellmunksgaard.com Note:the author is an invited lecturer for many dental organisations but has no financial interests and no formal links with any of these organisations. Contents Dedication viii Aesthetics 37 Foreword by Ronald E.Goldstein ix Facial composition 38 Preface xi Dentofacial composition 41 Dental composition 45 1 Treatment planning – assessment, Gingival composition 48 planning and treatment 1 Assessment 1 Planning 3 3 Choice of all-ceramic Diagnosis 3 systems 55 Risk assessment 3 Scientific rationale 55 Evidence-based decision making Rationale for all-ceramic and treatment 6 restorations 55 Presenting treatment plan proposals Physical and mechanical properties to the patient 9 of ceramic 58 Treatment 11 Uni-layer and bi-layer all-ceramic Clinical case study 12 systems 58 Assessment 12 Aetiology of fractures 59 Planning 13 Dental ceramics 60 Treatment 16 Silica-based ceramics 61 Alumina-based ceramics 65 2 The health, function and Zirconia-based ceramics 68 aesthetic triad 21 Longevity 69 Health 21 Metal–ceramic 69 The periodontium 22 Dicor and Cerestore 70 Restorative implications 29 IPS-Empress 1 70 Implants 29 In-Ceram Alumina 70 Function 30 Procera 70 Occlusion 30 Ceramic bridges (FPDs) 70 Phonetics 36 Clinical practice 73 vi Contents 4 Colour and shade analysis 77 Criteria for intra-radicular post selection 106 Scientific rationale 77 Coronal dentine and the ferrule The stimulus for colour 78 effect 106 The illuminant 78 Tapered vs.parallel 106 The object 79 Smooth vs.serrated 107 Sensation (the detector) 81 Passive vs.active 107 Synopsis of the stimulus for Direct vs.indirect technique 107 colour 83 Single- vs.multi-rooted teeth 109 Perception 83 Choice of luting agents 109 Tooth colour determination 85 Aesthetics 110 Physical variables 85 Types of cores 113 Physiological variables 86 Modes of failure 114 Psychological variables 86 Loss of retention 115 Dental variables 87 Post fractures 115 Other optical variables influencing Root fractures 116 colour 89 Pre-post placement assessment 117 Shade guides 90 Endodontic factors 117 Types of shade guide 91 Periodontal factors 117 Limitations of shade guides 93 Choice of definitive Instrumental assessment 93 restoration 118 Spectrophotometer 94 Remaining coronal dentine 118 Colorimeter 94 Tooth location 118 Digital camera and red,green,blue Summary 118 (RGB) devices 94 Non-vital teeth – clinical practice 118 Clinical practice 94 Ocular shade assessment 95 Instrumental shade assessment 96 6 Tooth preparation 125 5 Foundations and Scientific rationale 125 intra-radicular support 98 Reasons for extra-coronal Introduction 98 restorations 125 Vital teeth – scientific rationale 98 Biologic width 127 Vital teeth 98 Margin location 128 Retention 99 Margin geometry 130 Vital teeth – clinical practice 102 Preparation design 131 Pre-assessment for cores on vital Maintenance of dental hard tissue teeth 102 integrity 133 Radiographic evaluation 102 Cutting efficiency 135 Intra-oral evaluation 102 Clinical practice 135 Clinical sequalae for cores on vital Anterior tooth preparation 135 teeth 102 Assessment 136 Non-vital teeth – scientific rationale 103 Planning 136 Post materials 103 Treatment 137 Casting alloys 103 Posterior tooth preparation 140 Prefabricated metal 103 Assessment 140 Ceramics 104 Planning 140 Fibre 104 Treatment 141 Contents vii 7 Therapeutic temporary Impression materials 169 restorations 145 Primary determinant 172 Patient factors (risk assessment) 173 Introduction 145 Operator factors 174 Scientific rationale 145 Clinical practice 177 Health 145 Dental biological impressions 177 Function 147 Gingival biological impressions 179 Aesthetics 147 Biocompatibility 151 Strength 151 9 Try-in procedures 185 Palliative 151 Marginal integrity 152 Clinical practice 186 Preventing plaque accumulation 153 Extra-oral evaluation 186 Chromatic stability 155 Inspection of restoration on Handling characteristics and ease of trimmed die 187 fabrication 155 Inspection of restoration on Material selection 155 untrimmed die 188 Polymethyl methacrylate (PMMA) 156 Intra-oral evaluation 189 Polyvinyl ethylmethacrylate (PVEMA) 156 Bis-GMA resin 157 10 Cementation and dentine Bis-acryl resin composite 157 bonding agents 191 Urethane dimethacrylate (UDMA) Scientific rationale 191 resin 157 Types and properties of luting Clinical practice 157 agents 191 Fabrication 157 Zinc oxide eugenol (ZOE) 191 Matrices 158 Zinc phosphate (ZP) 192 Existing anatomical form 158 Polycarboxylate (PC) 192 Proposed anatomical form 158 Glass ionomer (GI) 192 Preformed metal and plastic Resin-modified glass ionomer crown forms 159 (RGI) 192 Techniques 159 Dual-polymerisation resins (DR) 192 Direct technique 160 Self-adhesive,dual-polymerisation Indirect technique 162 resins (SADR) 192 Direct–indirect technique 162 Self adhesive,auto-polymerisation resins (SAAR) 193 8 Biological impressions 165 Ceramic primers (CP) 193 Introduction 165 Efficacy of cementing agents 193 Scientific rationale 165 Adhesion 193 Secondary determinants 166 Occlusal stresses 194 Stock vs.custom trays 166 Marginal integrity and leakage 195 Inter- vs.intra-arch 166 Retention 196 Closed vs.open tray 167 Pre-treatment of abutment 197 One vs.two stages 167 Dentine bonding agents 197 Passive vs.non-passive 168 Efficacy 201 Warm vs.cold environment 168 Pre-treatment of intaglio surface 202 Manual vs.automated mixing 168 Clinical practice 203 Physical vs.chemical gingival retraction 168 Index 211 Dedication To my wife and soul companion, Samar, and my son Zayan. Foreword I have always thought that any teacher of beauty, tional and an esthetic result. Thus it is both including cosmetic dentistry, should have an refreshing and a true learning experience to dis- artistic “eye.” In my opinion, Irfan Ahmad falls cover Dr Ahmad’s unique way of how to accom- within this requirement. The first time I saw him plish his esthetic goals. lecture I was quite impressed with his under- It has been over thirty years since I wrote the standing and attention to all that is classified first edition of Esthetics in Dentistry. This was as esthetic. So, it is appropriate that Dr Ahmad the very first comprehensive textbook describing has authored Protocolsfor Predictable Aesthetic esthetic techniques both as an entity as well as a Dental Restorations. His approach to basic and vital part of interdisciplinary dentistry. Working advanced principles of esthetics is well grounded. with specialists for virtually all disciplines of Although each of us may have our own way of dentistry, this concept has now been finally doing a particular procedure we should never- accepted into what we consider the prevailing theless realize that there is more than one way to standard of care in both diagnosis and treatment achieve the same goal and therefore Dr Ahmad’s planning. unique approach to problems is well worth our Dr Ahmad understands this concept and thus attention. His stunning photography is both cre- he spends most of his text dealing with the details ative and educational, making step-by-step pro- of how he, and we, should be achieving greater cedures easier to comprehend. All too often we success with all ceramic crowns and bridges. Just see self-styled clinicians who both lecture and as I did in my first text, Dr Ahmad devotes a write as if they originated every single technique chapter to each of the essential six steps to a suc- they show and with little or no evidence to back cessful restoration. There is an important lesson up their claims. Therefore it is refreshing to see in spending an entire chapter on each step, and that Dr Ahmad relies on evidenced-based princi- that is not only to learn new tips on being more ples to back up his artistic talent. The uniqueness efficient and seeing if another method is better of our profession is that we are not all “clones,” than the one you currently use, but also that each each of us has his or her own “tricks” or tech- of the steps is a separate entity. This helps us con- nique to accomplish a common goal – that of stantly remember to spend an adequate amount pleasing the patient and achieving both a func- of time with attention to detail, so that in the end x Foreword we will have done our very best in each phase of this difference and I am so pleased he chose to the restoration. It is this attention to detail that share that “difference” with all of us. can make the difference between an ordinary and an extraordinary restoration. Dr Ahmad knows Roland E. Goldstein, DDS Preface The aim of this book is to furnish the clinician transport the reader through successive stages for with knowledge for providing aesthetic dental providing aesthetic dental restorations. Most restorations that are virtually indistinguishable chapters commence with scientific rationale and from natural teeth. Dental aesthetics is intangi- finish with clinical practice, applying theory to a ble, influenced by the wishes of the patient, ex- practical scenario. Whilst the learning curve at perience of the clinician, and the artistic and times seems onerous, once mastered the tech- technical skills of the ceramist. Aesthetics lies in niques can be expedited for making aesthetic the murky twilight between art and science. Art restorations that are predictable, functional is not enough to create aesthetic restorations, and long lasting. Furthermore, the systematic while science alone is inadequate for pleasing approach adopted in this book gains patient results. However, the clinical protocols necessary gratitude and creates clinical satisfaction. for aesthetic restorations are tangible, relying on I am indebted to Ronald Goldstein, who is biological concepts combined with scientific undoubtedly regarded as the pioneer of aesthetic research. Using the health, function and aesthetic dentistry. The two people who have spurred me (HFA) triad, the clinician and ceramist can on: Bernard Touati and Nitzan Bichacho, as well deliver prostheses that are durable and har- as eminent clinicians who have helped, directly monise with surrounding soft and hard tissues. or indirectly, with this project, including Avishai The appearance of dental restorations is subjec- Sadan, Gerard Chiche, Markus Blatz, Tom tive: one person’s Xanadu may be another’s Trinkner, William Liebenberg, Alan Gluskin, Inferno. Aesthetics is a passion, not a craft, and Homa Zadeh, Fereidoun Daftary, Stefano one that has to be sought rather than taught. Gracis, Mauro Fradeani, Douglas Terry, Stephen According to Carl Jung, ‘A man who has not Hancocks, RafiRomano, Galip Gürel, Alan Sidi, passed through the inferno of his passions has Eric van Doreen, Youval Elyat, Ervin Weiss, never overcome them’. Nitzan Fuhrer, Ilan Gilboa, members of the The layout of the book is a chronological European Academy of Esthetic Dentistry and clinical journey, starting with treatment planning Dentology study group, especially Sanjay Sethi, and ending with cementation. The intervening who founded Dentology five years ago for like- chapters between these start and end points minded clinicians.