Application of the Neutral Zone in Prosthodontics

The authors Joseph J. Massad, DDS, is Associate Professor in the Department of Prosthodontics at the University of Tennessee Health Center, School of Dentistry in Memphis, Tennessee, USA; Adjunct Associate Professor in the Department of Prosthodontics and Operative Dentistry at Tufts University School of Dental Medicine in Boston, Massachusetts, USA; Adjunct Associate Professor in the Department of Comprehensive Dentistry at the University of Texas Health Science Center, School of Dentistry in San Antonio, Texas, USA; Adjunct Associate Professor in the Department of Restorative Dentistry at Loma Linda University School of Dentistry, in Loma Linda, California, USA; Clinical Assistant Professor at the University of Oklahoma College of Dentistry in Oklahoma City, Oklahoma, USA; and Private Practice in Tulsa, Oklahoma, USA. David R. Cagna, DMD, MS, is a Professor in the Department of Prosthodontics, Associate Dean of Postgraduate Affairs & Director of Advanced Prosthodontics at the University of Tennessee Health Science Center, College of Dentistry, Memphis, Tennessee, USA; Diplomate & Director of the American Board of Prosthodontics; and Fellow of the American College of Prosthodontists. Charles J. Goodacre, DDS, MSD, is Distinguished Professor in the Department of Restorative Dentistry at Loma Linda University School of Dentistry in Loma Linda, California, USA; and Diplomate and Past-President of the American Board of Prosthodontics. Russell A. Wicks, DDS, MS, is Professor and Chairman in the Department of Prosthodontics at the University of Tennessee Health Science Center, College of Dentistry in Memphis, Tennessee, USA. Swati A. Ahuja, BDS, MDS, is Adjunct Assistant Professor in the Department of Prosthodontics at the University of Tennessee Health Science Center, College of Dentistry in Memphis, Tennessee, USA; and Prosthodontic Consultant at Lutheran Medical Center in New York City, New York, USA.

Foreword ix

Preface  xi

About the Companion Website xiii

1 Assessment of Edentulous Patients 1

Introduction  1

The Patient Interview 1

Patient Interview: Age 2

Patient Interview: Attitude 2

Patient Interview: Expectations 2

Patient Interview: Chief Complaint 3

Patient Interview: General Health 3

Patient Interview: Complete Denture Experience 3

Patient Interview: Denture Remake Frequency 4

Patient Interview: Patient Satisfaction 4

Patient Interview: Photographs, Diagnostic Casts, and Radiographs 4

The Facial Analysis  4

Facial Analysis: Facial Tissue Tone  5

Facial Analysis: Tooth and Denture Base Display  6

Facial Analysis: Midlines 6

Facial Analysis: Lip Mobility 7

Facial Analysis: Lip Dimension  7

Prosthetic Factors 8

Prosthetic Factors: Vertical Dimensions 8

Prosthetic Factors: Existing Dentures 8

Prosthetic Factors: Skeletal Relationship 9

Prosthetic Factors: Saliva 9

Prosthetic Factors: Oral Tolerance 10

Prosthetic Factors: Temporomandibular Joints 10

Prosthetic Factors: Oral Cancer Review 10

Oral Characteristics 11

Oral Characteristics: Palatal Throat Form 11

Oral Characteristics: Arch Size 11

Oral Characteristics: Maxillary Ridge Height 11

Oral Characteristics: The Palate 12

Oral Characteristics: Maxillary Ridge Contour 13

Oral Characteristics: The Maxillary Denture Foundation 13

Oral Characteristics: Mandibular Ridge Height 14

Oral Characteristics: Mandibular Ridge Contour 14

Oral Characteristics: Mandibular Muscle Attachments 14

Oral Characteristics: Mandibular Denture Foundation  15

Oral Characteristics: Maxillary Tuberosity Curve 15

Oral Characteristics: Vestibule 16

Oral Characteristics: Frenula Attachments 16

Oral Characteristics: Pterygomandibular Raphe 16

Oral Characteristics: Denture Bearing Soft Tissues 16

Oral Characteristics: Retromolar Pads 17

Oral Characteristics: Maxillary Ridge Crest to Resting Lip Length (Esthetic Space) 17

Oral Characteristics: Mandibular Ridge Crest to Resting Lip Length (Esthetic Space) 17

Oral Characteristics: Maximal Oral Opening 17

Oral Characteristics: Retromylohyoid Space 18

Oral Characteristics: Tongue Size 19

Oral Characteristics: Tongue Position 19

Oral Characteristics: The Neutral Zone 20

Summary  21

References  21

2 Orthopedic Resolution of Mandibular Posture 25

Introduction 25

Conditioning Abused Tissues and Stabilizing the Existing Prosthesis 26

Materials Properties and Technique 26

Technique 26

Re-establishing Orthopedic Mandibular Position 28

Summary  33

References  33

3 Definitive Impressions 35

Preimpression Considerations 35

Background  35

Impression Fundamentals 35

Impression Materials 36

Edentulous Impression Trays 37

Technique for Making Single Appointment Definitive Impressions for Conventional Complete Dentures 37

Tray Selection and Tray Adaptation 37

Fabrication of Tray Stops 38

Border Molding the Impression Tray 39

Final (Definitive) Impression  41

Techniques for Making Single Appointment Definitive Impressions for Implant-Assisted Complete Dentures and Immediate Dentures  43

Attachment Selection 43

Implant-Retained Overdentures 43

Tray Selection 43

Impression Technique 44

Implant-Retained and Supported Overdentures 45

Immediate Dentures 46

 Master Cast Production 47

Summary  48

References  48

4 Fabricating Record Bases, Occlusal Rims, and Mounting a Central Bearing Device 51

Introduction 51

Fabrication of Record Base and Occlusal Rims 51

Fabrication of Maxillary Wax Occlusal Rim 52

Fabrication of Neutral Zone Mandibular Occlusal Rim 56

Technique 56

Jaw Recorder Device (Central Bearing Device) 59

Jaw Recorder Device Assembly  59

Mounting the Jaw Recorder Device on Record Bases 59

Mounting of the Jaw Recorder for Implant Overdentures 61

Mounting the Jaw Recorder Device on Partially Edentulous Arches 61

Procedure 62

Summary  62

References  64

5 Developing an Esthetic Blueprint  65

Introduction 65

Contouring and Shaping the Maxillary Occlusal Rim 65

Summary  72

References  72

6 Registering the Maxillo-Mandibular Jaw Relationship 75

Introduction 75

Facebow Recording  75

Centric Relation Recording for the Edentulous Patient 76

Centric Relation Recording for the Partially Dentate Patient 83

Summary 86

References  86

7 Neutral-Zone Registration  89

Introduction 89

Recording the Physiologic Neutral Zone for Edentulous Patients 89

Technique 90

Recording the Physiologic Neutral Zone for a Dentate Patient 94

Technique 94

Summary  96

References  96

8 Second Laboratory Procedure: Selection and Arrangement of Prosthetic Teeth 99

Introduction 99

Indexing the Esthetic Blueprint Record 99

Indexing the Neutral Zone Record 100

Selection of Anterior Teeth 101

Maxillary Anterior Teeth Arrangement 102

Mandibular Anterior Teeth Arrangement  103

Selection of Posterior Teeth 105

Mandibular Posterior Teeth Arrangement 106

Maxillary Posterior Tooth Arrangement 108

Tooth Selection and Arrangement for the Partially Edentulous Patient 109

Summary  111

References 111

9 Trial Placement Appointment 113

Trial Placement 113

Evaluation of Esthetics  113

Evaluation of Phonetics 114

Evaluation of Occlusal Vertical Dimension (OVD)  116

Evaluation of Centric Contact Position 116

External Impressions 117

Technique 118

Summary  124

References 125

10 Denture Placement 127

Introduction 127

Placement of Immediate Dentures 127

Placement Procedures 129

Evaluation and Adjustment of Intaglio Surface 129

Technique 129

Evaluation and Adjustment of Denture Borders 131

Evaluating the Cameo Surface 133

Occlusal Evaluation and Correction 133

Subtractive Correction Technique 135

Additive Correction Technique 136

Patient Education and Instructions 137

Technique for Adhesive Application 138

Technique for Adhesive Removal 138

Home Care Instructions for Denture Patients 140

Postplacement Problems with New Dentures 140

Retention Problems 140

Soreness 141

Sore Throat 141

Speech Problems 141

Gagging 141

Summary  142

References 142

11 Use of CAD/CAM Technology for Recording and Fabricating Neutral-Zone Dentures  145

Introduction 145

Registering the Neutral Zone during Impression Making 145

Technique 145

Registering the Neutral Zone during Maxillo-Mandibular Records 147

Technique 147

Registering the Neutral Zone during the Trial Placement 147

Technique 147

Summary  150

References 151

Index 153