Basics of Dental Technology

About the Companion Website ix

Chapter 1 Introduction 1

1.1 Introduction 1

1.2 How to use this book 1

1.3 Equipment and instruments 1

1.4 Health and safety in the dental laboratory 5

1.5 Sterilisation and impression handling 6

1.6 Introduction to model making 8

1.7 Models for prosthodontics - casting primary impressions 9

1.8 Models for prosthodontics - boxing-in impressions 12

1.9 Models for prosthodontics - casting working (secondary) impressions 13

1.10 Models for prosthodontics - models for cobalt-chromium frameworks 13

1.11 Orthodontic study models 14

1.12 Introduction to sectional models 16

1.13 Producing a sectional model using a tray system (Figure 1.13.1) 17

1.14 Producing a sectional model using a pinned system 19

1.15 Sectioning the model 20

1.16 Introduction to articulating models 22

1.17 Articulating models on a simple hinge articulator 22

1.18 Articulating dentate models using the average position 23

1.19 Articulating edentulous models using the average position 25

1.20 Articulating models using a facebow 26

Chapter 2 Complete Prosthetics 31

2.1 Introduction to complete prosthetics 31

2.2 Construction of a close-fitting custom impression tray 32

2.3 Construction of a tray with spacer for edentulous cases 34

2.4 Construction of a tray for dentate or partially dentate cases 35

2.5 Construction of a windowed close-fitting tray 37

2.6 Construction of occlusal registration rims 38

2.7 Setting up denture teeth 42

2.8 Denture processing 47

2.9 Grinding and finishing the dentures 53

2.10 Denture repair 57

2.11 Relining a denture in the laboratory 60

2.12 Copy dentures 62

Chapter 3 Partial Prosthetics 65

3.1 Introduction to partial prosthetics 65

3.2 Classification 65

3.3 Component parts of partial dentures 66

3.4 Surveying 68

3.5 Designing partial dentures 71

3.6 Partial denture construction - acrylic resin 75

3.7 Partial denture construction - cobalt-chromium 77

Chapter 4 Fixed Prosthodontics 85

4.1 Restoration design 85

4.2 Metal restorations 86

4.3 Ditching the die 88

4.4 Producing a wax pattern 88

4.5 Investing the wax pattern 90

4.6 Casting and de-vesting the pattern 92

4.7 Finishing the casting 94

4.8 Metal-ceramic restorations 98

4.9 Producing a wax pattern for a metal bonded to ceramic framework 99

4.10 Investing the wax pattern 102

4.11 Casting the pattern 102

4.12 De-vesting and surface preparation 104

4.13 Ceramic application and build-up 105

4.14 Ceramic restorations 112

4.15 Producing a high-strength ceramic substructure 114

4.16 Veneering a high-strength ceramic substructure 115

4.17 Producing a resin-bonded crown on a refractory die 115

4.18 Post crowns 117

4.19 Bridges 118

4.20 Producing a cast metal fixed-fixed restoration 121

4.21 Producing a soldered metal fixed-fixed restoration 122

4.22 Soldering 123

4.23 Minimal preparation bridges 125

4.24 Producing a minimal preparation bridge (Maryland technique) 126

4.25 Digital dentistry 128

4.26 Using a laboratory-based CAD-CAM system 131

4.27 Producing a posterior single-unit substructure or restoration using a reduction technique 132

4.28 Producing a bridge substructure 134

4.29 Removable Partial Denture Design 134

4.30 Implant-supported prosthodontics 139

Chapter 5 Orthodontics 141

5.1 Introduction to orthodontics 141

5.2 Classification of malocclusions 142

5.3 Theory of tooth movement 143

5.4 Basic wire bending techniques 144

5.5 Making passive components 146

5.6 Producing ball-ended clasps 146

5.7 The Adams clasp 147

5.8 Producing a southend clasp 148

5.9 Active appliances 149

5.10 Palatal finger spring (guarded) 150

5.11 Making a T-spring 152

5.12 Double cantilever or Z-spring 152

5.13 Buccal canine retractor 153

5.14 The Roberts retractor 154

5.15 Producing baseplates 155

5.16 Producing biteplanes 156

5.17 Extra-oral anchorage 156

5.18 Functional appliance design 157

5.19 Producing an Andresen appliance 157

5.20 Twin-block appliance 158

5.21 Fixed orthodontic appliances 160

5.22 Retainer appliance design 160

5.23 Repair and modification of orthodontic appliances 162

5.24 Making tooth positioners 164

5.25 Sports Mouthguards 165

Chapter 6 Occlusion 167

6.1 Introduction to occlusion 167

6.2 Occlusal schemes 168

6.3 Articulators 170

6.4 Facebows 171

6.5 Summary 171

Chapter 7 Shade, Colour and Size Determination for Dental Appliances 173

7.1 Introduction to aesthetics 173

7.2 Colour terminology 173

7.3 Shade guides 173

7.4 Selecting teeth for complete denture patients 175

Appendix Tooth Morphology 177

Glossary 179

Index 181