Protocols for Predictable Aesthetic Dental Restorations

Irfan Ahmad has a private dental practice on the outskirts of London, UK. He is an active member of the European Academy of Esthetic Dentistry. He writes extensively on the topic of aesthetic restorations and is a popular invited speaker at dental conferences across the world. His publications number over 120 in peer reviewed international dental journals, and he is the sole author of two books, Digital and Conventional Photography: A Practical Clinical Manual and A Clinical Guide to Anterior Dental Aesthetics.

Dedication viii

Foreword by Ronald E. Goldstein ix

Preface xi

1 Treatment planning – assessment, planning and treatment 1

Assessment 1

Planning 3

Diagnosis 3

Risk assessment 3

Evidence-based decision making and treatment 6

Presenting treatment plan proposals to the patient 9

Treatment 11

Clinical case study 12

Assessment 12

Planning 13

Treatment 16

2 The health, function and aesthetic triad 21

Health 21

The periodontium 22

Restorative implications 29

Implants 29

Function 30

Occlusion 30

Phonetics 36

Aesthetics 37

Facial composition 38

Dentofacial composition 41

Dental composition 45

Gingival composition 48

3 Choice of all-ceramic systems 55

Scientific rationale 55

Rationale for all-ceramic restorations 55

Physical and mechanical properties of ceramic 58

Uni-layer and bi-layer all-ceramic systems 58

Aetiology of fractures 59

Dental ceramics 60

Silica-based ceramics 61

Alumina-based ceramics 65

Zirconia-based ceramics 68

Longevity 69

Metal–ceramic 69

Dicor and Cerestore 70

IPS-Empress 1 70

In-Ceram Alumina 70

Procera 70

Ceramic bridges (FPDs) 70

Clinical practice 73

4 Colour and shade analysis 77

Scientific rationale 77

The stimulus for colour 78

The illuminant 78

The object 79

Sensation (the detector) 81

Synopsis of the stimulus for colour 83

Perception 83

Tooth colour determination 85

Physical variables 85

Physiological variables 86

Psychological variables 86

Dental variables 87

Other optical variables influencing colour 89

Shade guides 90

Types of shade guide 91

Limitations of shade guides 93

Instrumental assessment 93

Spectrophotometer 94

Colorimeter 94

Digital camera and red, green, blue (RGB) devices 94

Clinical practice 94

Ocular shade assessment 95

Instrumental shade assessment 96

5 Foundations and intra-radicular support 98

Introduction 98

Vital teeth – scientific rationale 98

Vital teeth 98

Retention 99

Vital teeth – clinical practice 102

Pre-assessment for cores on vital teeth 102

Radiographic evaluation 102

Intra-oral evaluation 102

Clinical sequalae for cores on vital teeth 102

Non-vital teeth – scientific rationale 103

Post materials 103

Casting alloys 103

Prefabricated metal 103

Ceramics 104

Fibre 104

Criteria for intra-radicular post selection 106

Coronal dentine and the ferrule effect 106

Tapered vs. parallel 106

Smooth vs. serrated 107

Passive vs. active 107

Direct vs. indirect technique 107

Single- vs. multi-rooted teeth 109

Choice of luting agents 109

Aesthetics 110

Types of cores 113

Modes of failure 114

Loss of retention 115

Post fractures 115

Root fractures 116

Pre-post placement assessment 117

Endodontic factors 117

Periodontal factors 117

Choice of definitive restoration 118

Remaining coronal dentine 118

Tooth location 118

Summary 118

Non-vital teeth – clinical practice 118

6 Tooth preparation 125

Scientific rationale 125

Reasons for extra-coronal restorations 125

Biologic width 127

Margin location 128

Margin geometry 130

Preparation design 131

Maintenance of dental hard tissue integrity 133

Cutting efficiency 135

Clinical practice 135

Anterior tooth preparation 135

Assessment 136

Planning 136

Treatment 137

Posterior tooth preparation 140

Assessment 140

Planning 140

Treatment 141

7 Therapeutic temporary restorations 145

Introduction 145

Scientific rationale 145

Health 145

Function 147

Aesthetics 147

Biocompatibility 151

Strength 151

Palliative 151

Marginal integrity 152

Preventing plaque accumulation 153

Chromatic stability 155

Handling characteristics and ease of fabrication 155

Material selection 155

Polymethyl methacrylate (PMMA) 156

Polyvinyl ethylmethacrylate (PVEMA) 156

Bis-GMA resin 157

Bis-acryl resin composite 157

Urethane dimethacrylate (UDMA) resin 157

Clinical practice 157

Fabrication 157

Matrices 158

Existing anatomical form 158

Proposed anatomical form 158

Preformed metal and plastic crown forms 159

Techniques 159

Direct technique 160

Indirect technique 162

Direct–indirect technique 162

8 Biological impressions 165

Introduction 165

Scientific rationale 165

Secondary determinants 166

Stock vs. custom trays 166

Inter- vs. intra-arch 166

Closed vs. open tray 167

One vs. two stages 167

Passive vs. non-passive 168

Warm vs. cold environment 168

Manual vs. automated mixing 168

Physical vs. chemical gingival retraction 168

Impression materials 169

Primary determinant 172

Patient factors (risk assessment) 173

Operator factors 174

Clinical practice 177

Dental biological impressions 177

Gingival biological impressions 179

9 Try-in procedures 185

Clinical practice 186

Extra-oral evaluation 186

Inspection of restoration on trimmed die 187

Inspection of restoration on untrimmed die 188

Intra-oral evaluation 189

10 Cementation and dentine bonding agents 191

Scientific rationale 191

Types and properties of luting agents 191

Zinc oxide eugenol (ZOE) 191

Zinc phosphate (ZP) 192

Polycarboxylate (PC) 192

Glass ionomer (GI) 192

Resin-modified glass ionomer (RGI) 192

Dual-polymerisation resins (DR) 192

Self-adhesive, dual-polymerisation resins (SADR) 192

Self adhesive, auto-polymerisation resins (SAAR) 193

Ceramic primers (CP) 193

Efficacy of cementing agents 193

Adhesion 193

Occlusal stresses 194

Marginal integrity and leakage 195

Retention 196

Pre-treatment of abutment 197

Dentine bonding agents 197

Efficacy 201

Pre-treatment of intaglio surface 202

Clinical practice 203

Index 211