MATERIALS USED IN DENTISTRY 8184735103, 9788184735109

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Materials Used in Dentistry

Materials Used in Dentistry

Senior Commissioning Editor: P. Sangeetha Managing Editor: Dr. Binny Mathur Production Editor: Divya Ganesan Compositor: Olympus Premedia Pvt Ltd. Manager Manufacturing: Anil Kumar Gauniyal Copyright © 2013 by Wolters Kluwer Health (India) 10th Floor, Tower C Building No. 10 Phase – II DLF Cyber City Gurgaon Haryana – 122 002 All rights reserved. T is book is protected by copyright. No part of this book may be reproduced in any form or by any means, including photocopying, or utilized by any information storage and retrieval system without written permission from the copyright owner. T e publisher is not responsible (as a matter of product liability, negligence, or otherwise) for any injury resulting from any material contained herein. T is publication contains information relating to dental materials and their clinical applications that should not be construed as specifi c instructions for individual patients. Manufacturers’ product information and package inserts should be reviewed for current information, including contraindications, dosages, and precautions. All products/brands/names/processes cited in this book are the properties of their respective owners. Reference herein to any specifi c commercial products, processes, or services by trade name, trademark, manufacturer, or otherwise is purely for academic purposes and does not constitute or imply endorsement, recommendation, or favoring by the publisher. T e views and opinions of authors expressed herein do not necessarily state or refl ect those of the publisher, and shall not be used for advertising or product endorsement purposes. Care has been taken to confi rm the accuracy of the information presented and to describe generally accepted practices. However, the authors, editors, and publishers are not responsible for errors or omissions or for any consequences arising from application of the information in this book and make no warranty, expressed or implied, with respect to the currency, completeness, or accuracy of the contents of the publication. Application of this information in a particular situation remains the professional responsibility of the practitioner. Readers are urged to confi rm that the information, especially with regard to drug dose/usage, complies with current legislation and standards of practice. Please consult full prescribing information before issuing prescription for any product mentioned in the publication. T e publishers have made every e ort to trace copyright holders for borrowed material. If they have inadvertently overlooked any, they will be plea sed to make the necessary arrangements at the first opportunity. First Edition, 2013 ISBN-13: 978-81-8473-510-9 Published by Wolters Kluwer (India) Pvt. Ltd., New Delhi. Printed and bound at Sanat Printers, Haryana.

Here is a fundamental book on dental materials for dentists “with a di erence.” Dentists are clinical scientists who handle a plethora of dental materials in their day-to-day practice. A thorough knowledge of the physics, chemistry, and biological reactivity of these materials is necessary for their optimal use and application in clinical practice. T is book is an attempt to handle this complex subject in a simplified manner for better understanding. Good illustrations, diagrams, photographs, and appropriately incorporated flowcharts make it an ideal foundation for budding dentists. T ough it is focussed primarily for use by graduate students, the book promises to be an interesting and inspiring reference text for postgraduate students as well because of its updated content on recent advances and latest techniques. T e entire subject is systematically organized and the chapters are classified into appropriate subheadings which would enable the students to approach their topic of choice with ease. T e chapter on biomaterials traces the evolution of materials over the past five decades and highlights the newer generations which use application of tissue engineering and nanotechnology. T e recent generation of biomaterials mimics nature and is bioinert, making these materials safe to the adjoining tissues, and at the same time is bioresorbable, to be replaced suitably by superior native tissue. T e advent of bioactive materials has been emphasized well in this book; these materials are found helpful in regenerating lost or even diseased tissue. Restorative materials have been classified as direct and indirect with necessary updates, based on their properties and uses. Both traditional and recent materials are discussed in detail. Direct filling gold, which is often neglected in textbooks, finds its place under direct restorative materials. T e chapter on indirect restorative and implant materials provides details about casting alloys, indirect composites, and dental ceramics, with a special mention of implant materials, which are “en vogue.” Here, I would reiterate that restorative dentistry has taken a turn for the good—from a past when the tooth was being modified to suit the material to the present when the material is modified to suit the tooth. Auxiliary materials and techniques are handled extensively in one section, which deals exclusively with materials used in the dental laboratory, with the exception of bonding agents. Also, materials used in preventive dentistry, which form an important aspect of patient management today, are presented independently in a separate section. Materials used in various dental specialties, such as Orthodontics, Periodontics, and Endodontics, are smartly amalgamated into this one book, which is comprehensive. Local anesthetics and suture materials are detailed under the section “Surgical and Periodontal Materials.” T ese additions make this book a “stand-alone text” among its contemporaries. T is is a multiauthor endeavor with experienced academicians and clinicians participating to create a book on applied material sciences. It deals with almost all the common materials used in dentistry, obviating the need of students having to search through various specialty books for the specific materials. T e appendix, on the list of books recommended, will be useful as additional information for the students. T is book is edited and authored by Professor Mahalaxmi, who is well known to me as a dedicated teacher with over two and a half decades of teaching experience in dentistry. She is also an accomplished clinician who specializes in the use of lasers and microscopes in Endodontics. She has to her

vi

Foreword

credit many national and international publications and is a frequently invited speaker at national and international forums. She has active membership in many scientific groups and associations and is also a reviewer for popular international journals. Her organizing and leadership qualities are amply demonstrated in the publication of this comprehensive and contemporary textbook—a fantastic “hybrid composite” of academics and application. T e role of the author as an ever-learning teacher and guide is clearly evident in the studentfriendly nature of this book. Consequently, the book provides appropriate additional information, highlights recent concepts, and includes a list of questions that are frequently asked in competitive entrance examinations at the end of the chapters. I am sure these features will be very useful to any student of dental science. To summarize, I see this book as “an inspirational substructure, the funda menta ls, on which to build your dental future…”

Dr. A. Parameswaran bsc, md s, f r sh Former Principal Tamilnadu Govt. Dental College & Hospital Chennai

T e year was 1980. As a first-year BDS student, thrown into the ocean of dentistry, I was totally clueless about the intricacies of the enormous array of dental materials being taught, not understanding why I needed to be so thorough with so many aspects of physics, chemistry, and other disciplines I thought I had seen the last of! It took me a couple more years, when I started using these very materials clinically, to actually understand the critical importance of their properties and behavior. Probably the seed of this book was sown then. Years later, when I really started appreciating the advantages of di erent materials and respecting their drawbacks, the thought of sharing this understanding with others started taking root within me. In course of time, this thought grew stronger in my mind and eventually resulted in taking the shape of the present book. As Charles William Eliot observed: “Books are the quietest and most constant of friends; they are the most accessible and wisest of counsellors, and most patient of teachers.” T is book endeavors to analyze and review the performance of the materials used in dentistry so that the reader can appreciate the intricate nuances of the materials that he/she uses regularly in dayto-day practice. T is book neither covers all the materials used in dentistry nor does it extensively elaborate on all aspects of the materials covered. Instead, the book focusses on the basics of the most prevalent materials in clinical practice so as to enable the clinician to make the best use of the material in the given clinical situation. Keeping this objective in mind, the use of the materials in some common clinical scenarios has been discussed in considerable detail in order to clearly highlight their di erent ideally required properties as well as their biocompatibility requirements. T e discussion of properties and uses is amply supported with good-resolution photographs of the clinical steps where applicable. T e various uses have also been illustrated so that the student can grasp the applications of the material in an easier manner. Another important feature of this book is the highlighted text in several chapters that helps the students in preparing for the national postgraduate entrance examinations. Further, the book includes relevant materials used in endodontic, preventive, periodontal, and surgical procedures so that students can use this book for all the years of their dental training. T e inputs in this textbook are from various eminent practitioners and specialists who have very kindly contributed chapters on their respective areas; the credit for the salient features of this book goes to all of them. However, any drawbacks are purely the result of my ignorance for which I take the full responsibility. S. Mahalaxmi

Writing a textbook is a formidable challenge; the author or editor’s role a Herculean task worthy of comparison with a gladiator! T e thoughts do not flow, the publisher’s clock is ticking, time is running out, and the contributors are nonresponsive at times; simultaneously, many other issues, related and unrelated, are clamoring for attention… If the gladiator (author) has been able to overcome all the obstacles and deliver the book, it is mainly due to the crucial support provided either directly or indirectly by many people. “What the teacher is, is more important than what he teaches.” Karl Menninger

T is book is dedicated to all my teachers, undergraduate students, and postgraduate students of the past and the present, who have taught me the subject and many aspects of life, sometimes in the least expected way. But nevertheless, each and every one of them has contributed to whatever little knowledge that I possess. I am very much still a student eager to learn and share. T is book would never have seen the light of the day, but for the untiring e ort, encouragement, and perseverance of solely one person, the Commissioning Editor, Ms. Sangeetha Parthasarathy. It must have been a good experience for her too, since I have asked her to do a lot of things that her job may not have prepared her for! What I have achieved today is totally due to the sacrifices of my parents, my husband, Dr. K.R. Sekar, and my sons, Pradeep and Anirudh, who have put up with my absence, literally and figuratively, from their lives during the development of this book. My heartfelt gratitude to the SRM University and SRM Dental College, the Chancellor, Chairman, Vice-Chancellor, and the management for providing me an excellent academic platform to nurture my academic interests. T e Dean, Dr. K. Ravi; Vice Principal, Dr. K. Rajkumar; and all faculty members of this institution have never failed to lend a helping hand whenever needed. I will be failing in my duty if I do not acknowledge the immense help from all the sta members of my own department, who have taken care of the department in my virtual absence, contributed extensively to this textbook, and put up with my idiosyncrasies during the book-writing journey! Here, I would like to make a special mention of some sta members who have done more than their share of work in helping me shape this book: Dr. Sujatha, Dr. Karthikeyan, Dr. Srinivasan, and Dr. Madhana. Dr. Ponsekar Abraham took the whole burden of prosthetic materials and also helped in editing many of my own chapters. I would like to personally thank each and every contributor of this book, who have selflessly worked to achieve a high degree of excellence in their work; the contributors on the list and many more o it, such as Dr. Anita Prakash, Dr. Vandana James, Dr. J. Mahendran, Dr. Saranya, Dr. Jwal Banker, Dr. Shailaja, and Dr. M.S. Sathya. T e highlight of this book is the excellent photographs; the credit for this goes to my professional photographers, Dr. Sathyakumar, Associate Professor, and Dr. Nighil Mohan, final-year postgraduate student, who must have clicked a million photos! My sincere thanks also to Dr. Sri Vidhya, who has so painstakingly, and so beautifully, drawn most of the illustrations in this book. I would like to place on record the perfectionistic e orts of Dr. Vijay Amritraj in creating perfect clinical work in the form of cavity preparations, manipulations, restorations, wax patterns, etc., for the photographic illustrations.

x

Acknowledgments

Many friends from across the globe have contributed their excellent work in the form of photographs for this book and I would like to thank each and every one of them: Dr. Antonis Chaniotis, Greece; Dr. Arun K. Velu, Chennai, India; Dr. Edward McLean, USA; Dr. Kenneth Serota, Canada; Dr. Liviu Steier, England; Dr. Marga Ree, Netherlands; Dr. Maxim Belograd, Ukraine; Dr. Sujithra, CADET, Chennai, India; and Dr. Vasudevan, Chennai, India. I also thank all my patients who have generously allowed me to photograph their teeth. Mr. Dhansekar, of Apt Dental Lab, Salem, deserves a special mention for his contribution of excellent photographs to the chapters on indirect restorations. Credit also goes to the dental companies who have been generous in sharing their product photographs such as GC India, Anabond-Stedman, 3M ESPE, and Ivoclar Vivadent. I am ever indebted to my very good friend, Dr. Madhav Murthy, formerly of 3M ESPE, for always lending a helping hand, whenever required. A very special thanks to Mr. Vinod Kumar, Mr. Manoj Kumar, and Mr. Vijay Kumar, of Vijay Dental Depot, and Mr. Muthukumar, of Apt Dental, Chennai, for their immense help and support in fulfilling my various requests. My sincere appreciation of the publishers, Wolters Kluwer India, for having patiently waited for me to finish writing and editing and for having put out an excellent quality product. I would like to specifically mention Ms. Sangeetha Parthasarathy, Dr. Binny Mathur, Ms. Divya Ganesan, Mr. Rajiv Banerji, and Mr. M.S. Mani of Wolters Kluwer India. T ey have been very professional and reliable in their approach and have worked meticulously to bring out this book in its present form. A very special thanks to Dr. Maya Saranathan, the previously anonymous dentistry editor, who meticulously went through each and every word and critically reviewed the chapters. I would like to acknowledge the help rendered by Dr. Arathi Ganesh, Professor, Sri Ramachandra University; Dr. Ida de Noronha de Ataide, Dean, Goa Dental College & Hospitals; and Dr. S. Vidhya, of my own department, for having critically reviewed many of the chapters. S. Mahalaxmi

* Ponsekar Abraham A. md s Professor Department of Prosthodontics and Crown & Bridge SRM Dental College Chennai, Tamil Nadu

Rajesh Ebenezar md s Reader Department of Conservative Dentistry and Endodontics SRM Dental College Chennai, Tamil Nadu

Shifa Shamsudeen Arshad md s Consultant Pediatric Dentist WE Little Coimbatore, Tamil Nadu

Marina Fernandes md s Assistant Professor Department of Conservative Dentistry & Endodontics Goa Dental College and Hospital Bambolim, Goa

Ida de Noronha de Ataide md s Dean, Professor and Head Department of Conservative Dentistry & Endodontics Goa Dental College and Hospital Bambolim, Goa Alka Banker md s, Diplomate of T

Bagavad Gita md s Professor Department of Periodontology Sree Balaji Dental College & Hospital Chennai, Tamil Nadu

e Indian

Board of Orthodontics

Professor and Head Department of Orthodontics Goenka Research Institute of Dental Science Gandhinagar, Gujarat Deepti Bindal md s Reader Department of Conservative Dentistry and Endodontics PDM Dental College & Research Institute Bahadurgarh, Haryana Anil Chandra md s Professor Department of Conservative Dentistry & Endodontics Faculty of Dental Sciences King George’s Medical University Lucknow, Uttar Pradesh *Names are arranged alphabetically by surnames.

Mukesh Hasija md s Chief Resident Department of Conservative Dentistry & Endodontics Faculty of Dental Sciences King George’s Medical University Lucknow, Uttar Pradesh Karthikeyan K. md s Reader Department of Conservative Dentistry and Endodontics SRM Dental College Chennai, Tamil Nadu Rajkumar K. md s Professor Department of Conservative Dentistry and Endodontics SRM Dental College Chennai, Tamil Nadu

xii

Contributors

Anitha K.V. md s Senior Lecturer Department of Prosthodontics and Crown & Bridge SRM Dental College Chennai, Tamil Nadu Madhana Madhubala M. md s Senior Lecturer Department of Conservative Dentistry and Endodontics SRM Dental College Chennai, Tamil Nadu Sneha Mirchandani bd s Private Practitioner Ahmedabad, Gujarat Jeanne Monteiro md s Senior Lecturer Department of Conservative Dentistry & Endodontics Goa Dental College and Hospital Bambolim, Goa

Prakash P.S.G. md s Reader Department of Periodontics SRM Dental College Chennai, Tamil Nadu Hemalatha R. md s Professor and Head Department of Pedodontics & Preventive Dentistry SRM Dental College Chennai, Tamil Nadu Venkat R. md s Senior Lecturer Department of Prosthodontics and Crown & Bridge SRM Dental College Chennai, Tamil Nadu Murali R.V. md s Professor and Head Department of Orthodontics Sree Balaji Dental College & Hospital Chennai, Tamil Nadu

Meena N. md s Professor Department of Conservative Dentistry & Endodontics V.S. Dental College & Hospital Bengaluru, Karnataka

Jaya Ranganathan md s Professor and Head Department of Conservative Dentistry and Endodontics Priyadarshini Dental College and Hospital T iruvallur, Tamil Nadu

Srinivasan N. md s Senior Lecturer Department of Conservative Dentistry and Endodontics SRM Dental College Chennai, Tamil Nadu

Mahalaxmi S. md s Professor and Head Department of Conservative Dentistry and Endodontics SRM Dental College Chennai, Tamil Nadu

Elavenil P. md s Reader Department of Oral & Maxillofacial Surgery SRM Dental College Chennai, Tamil Nadu

Sathyakumar S. md s Reader Department of Conservative Dentistry and Endodontics SRM Dental College Chennai, Tamil Nadu

Contributors

Vasanth S. bd s Private Practitioner Vasanth Dental Center Chennai, Tamil Nadu Vidhya S. md s Reader Department of Conservative Dentistry and Endodontics SRM Dental College Chennai, Tamil Nadu Kavitha Sanjeev md s Professor Department of Conservative Dentistry and Endodontics SRM Dental College Chennai, Tamil Nadu

Sai Shamini md s Reader Department of Conservative Dentistry & Endodontics Madha Dental College & Hospital Chennai, Tamil Nadu Prakash V. md s Professor Department of Conservative Dentistry and Endodontics Sree Balaji Dental College & Hospital Chennai, Tamil Nadu Sujatha V. md s Professor Department of Conservative Dentistry and Endodontics SRM Dental College Chennai, Tamil Nadu

xiii

Foreword Preface Acknowledgments Contributors

v vii ix xi

Introduction to Dental Materials Structure of Matter Properties of Dental Materials Light and Color Metals and Alloys Tarnish and Corrosion Principles of Adhesion Polymers in Dentistry

3 8 19 42 63 77 91 102

Science of Biomaterials Biocompatibility of Dental Materials

119 129

Denture-Based Materials

149

Dental Amalgam Mercury Dental Cements Glass Ionomer Cements Composite Resins Direct Filling Gold

195 222 230 257 275 306

Dental Casting Alloys Dental Ceramics Indirect Composite Resins Dental Implant Biomaterials

325 339 371 382

xvi

Table of Contents at a Glance

Bibliography Index

Bonding and Bonding Agents Impression Materials and Techniques Gypsum and Die Materials Dental Waxes Investment Materials and Techniques Casting Procedures Finishing and Polishing

397 415 461 483 500 521 539

Antiplaque Agents Materials Used for Remineralization Pit and Fissure Sealants

563 581 593

Soldering and Welding Orthodontic Material Science

607 621

Root Canal Irrigants Intracanal Medicaments Calcium Hydroxide Root Canal Sealers Materials Used for Obturation Retrograde Filling Materials Materials Used for Tooth Whitening

645 656 666 680 695 708 724

Local Anesthetic Agents Suture Materials Biomaterials Used in Periodontology

739 760 778 799 809

Foreword Preface Acknowledgments Contributors

v vii ix xi

Introduction to Dental Materials

3

Historical Perspective Selection of Dental Materials Standards and Specifications for Dental Materials Research Trends in Dental Materials Conclusion

3 4

Structure of Matter

8

5 6 7

Atomic Structure: Fundamental Concepts Periodic Table Interatomic Bonding Interatomic Primary Bonds Interatomic Secondary Bonds Bond Distance and Bond Energy States of Matter Classical States Nonclassical States Unit Cell Atomic Packing Factor Conclusion

9 10 12 12 13 14 14 15 16 17 17 18

Properties of Dental Materials

19

Optical Properties Chemical Properties Solubility Chemical Erosion Leaching Adhesive Properties T ermal Properties Specific Heat T ermal Conductivity T ermal Di usivity Coe cient of T ermal Expansion

20 20 20 21 21 21 21 22 22 23 23

Rheological Properties Flow Creep Viscosity Viscoelasticity Behavior of Liquids T ixotropy Mechanical Properties Stress Strain Poisson’s Ratio Hooke’s Law Physicomechanical Properties Modulus of Elasticity (Elastic Modulus, Young’s Modulus) Proportional Limit Elastic Limit Yield Point Yield Strength Ultimate Tensile Strength Ductility Brittleness Resilience Toughness Other Physical Properties Malleability Hardness and Hardness Testing Tear Strength Transverse Strength (Flexural Strength/Modulus of Rupture) Tensile Strength Diametral Compression Test Compressive Strength Wear Dimensional Change How Alloys A ect Physical Properties Conclusion

24 24 24 25 25 25 26 26 26 28 29 30 31 31 31 32 32 32 32 32 33 33 33 33 33 34 37 38 38 39 39 39 40 41 41

Light and Color

42

Concepts of Color Perception Light Illuminant (Light Source) Interaction of Light Source with an Object Reflection

43 43 43 46 46

xviii

Detailed Table of Contents

Refraction Transmission Di raction Absorption Scattering Color Vision Color of Teeth Factors Influencing Color Perception Repeated Viewing of Colors Age and Sex Surroundings Dimensions of Color Hue Chroma Value Metamerism Fluorescence Additive and Subtractive Colors Opalescence Measurement of Color Munsell System CIE L*a*b System Shade Selection and Natural Teeth Dental Shade Guides and Colorimeters Color Matching in Clinical Practice Factors Influencing Shade Selection Squint Test Steps in Shade Matching Dental Digital Photography and Color Conclusion

46 47 47 48 48 48 48 49 49 49 50 50 50 50 50 52 53 53 53 54 55 55 56 56 57 58 59 59 61 62

Metals and Alloys

63

Periodic Table Atomic Structure of Metals Unit Cell and Lattice Structure Grains and Grain Boundaries Metallic Bonds Properties of Metals Physical Properties Chemical Properties Mechanical Properties Solidification of Metals Nucleus Formation Alloys Classification of Alloys Solid Solutions Types of Solid Solutions Phases of Alloys Properties of Alloys Density Liquidus and Solidus

64 64 64 65 65 65 65 66 66 67 68 68 69 69 69 70 70 70 70

Yield Strength Hardness Noble Metals Gold Platinum Palladium Other Noble Metals Base Metals Silver Copper Zinc Tin Indium Gallium Nickel Phases of Dental Alloys Phase Diagrams Alloy-Strengthening Mechanisms Tempering and Quenching Age Hardening Conclusion

70 71 71 71 71 71 71 72 72 72 72 72 72 72 72 73 73 75 75 76 76

Tarnish and Corrosion

77

Tarnish Causes of Tarnish Corrosion Basic Corrosion Process Causes of Corrosion Factors A ecting Corrosion Classification of Corrosion Chemical/Dry Corrosion Electrochemical/Electrolytic/Wet Corrosion Biological Corrosion Tarnish and Corrosion of Dental Restorations Tarnish and Corrosion of Restorative Materials Noble Metal Base Metal Alloys Stainless Steel Amalgam NiTi Alloys Dental Amalgam Restoration and Crevice Corrosion Evaluation of Tarnish and Corrosion Resistance Clinical Significance of Galvanic Currents Galvanic Shock Biocompatibility Issues

78 78 79 79 79 79 80 80 80 84 85 85 85 85 86 86 87 87 87 88 88 89

Detailed Table of Contents

Protection Against Corrosion Conclusion

89 89

Principles of Adhesion

91

Concept of Adhesion in Dentistry Adhesion Between Solids Adhesion Between Solid and Liquid Criteria for Adhesion Substrate Wettability Surface Energy Viscosity Surface Roughness T eories of Adhesion Mechanical Adhesion T eory Adsorption Adhesion (Chemisorption) T eory Di usion Adhesion T eory Electrostatic Adhesion T eory Failure of Adhesion Clinical Considerations Clinical Applications Factors A ecting Adhesion Adhesion Between Dental Materials and Tooth Substrate Bond Strength Test Methods Macrobond Strength Tests Microbond Strength Tests Conclusion

92 92 92 93 93 93 94 95 95 96 96

Polymers in Dentistry Ideal Properties of Dental Polymers History Classification of Polymers Physical Properties of Polymers Deformation and Recovery Solvation Properties T ermal Properties Chemistry of Polymers Polymerization Reaction Addition Polymerization/Chain Reaction Condensation Polymerization (Step-Growth Polymerization) Copolymerization Significance of Copolymerization Cross-Polymerization Chemical Stages of Polymerization Induction Propagation Chain Transfer

96 97 97 97 98 98 98 99 100 100 100 101

102 102 103 103 104 104 105 105 105 106 106 106 107 107 107 107 107 108 109

xix

Termination Inhibition of Polymerization Applications of Resins in Dentistry Unfilled Resins Direct Filling Resins Maxillofacial Prosthetic Materials Denture Teeth and Acrylic Facings Temporary Crown and Bridge Materials (Temporization Material) Resinous Die Materials Other Applications in Dentistry Adverse E ects of Dental Polymers Conclusion

109 109 109 109 112 112 113

Science of Biomaterials

119

Ideal Requirements of a Biomaterial Surface Characteristics of Biomaterials Classification Bioinert Biomaterials Bioactive Biomaterials Bioresorbable Biomaterials Biomaterial–Tissue Interaction Biomaterials for Dental Applications Metals Ceramics Polymers Natural Materials (Biomimetic Materials) Reinforced Materials Biocompatibility Tissue Engineering Requirements of a Sca old Material Conclusion

120 120 121 121 121 121 121 122 123 123 124

Biocompatibility of Dental Materials Adverse E ects of Dental Materials Systemic Toxicity Local Toxicity Allergic Reactions Other Reactions Methods for Evaluation of Biocompatibility In Vitro Tests Animal Tests Usage Tests

113 114 115 116 116

125 126 127 127 127 128

129 130 130 130 131 131 132 132 133 134

xx

Detailed Table of Contents

Ethical Issues Regarding Animal and Human Usage in Biocompatibility Testing Test Programs for the Biological Testing of Dental Materials Linear Progression of Tests Nonlinear Progression of Tests Biocompatibility Testing Standards Drawbacks of Standards Biocompatibility of Dental Materials Zinc Phosphate Cement Zinc Polycarboxylate Cement Zinc Oxide Eugenol Cement Calcium Hydroxide Glass Ionomer Cement Silver Amalgam Composite Resin Ceramics Dental Casting Alloys Wrought Alloys Denture Base Resins Impression Materials Endodontic Materials Conclusion

Denture-Based Materials History General Uses of Denture Base Resins Ideal Properties of Denture Base Materials Classification Polymethylmethacrylate Properties Heat-Activated Resin Manipulation Chemically Cured Resins Properties Uses Manipulation Fluid/Pour Type Resins Light-Activated Resin Packaging Technique Properties Microwave-Polymerized PMMA Technique Reline Resins

136 137 137 138 138 139 139 140 140 140 140 141 141 142 143 143 143 144 144 145 146

149 150 151 151 152 152 153 154 155 162 162 163 163 164 165 165 166 166 167 167 168

Methods of Relining and Rebasing Denture Liners Classification Properties Tissue Conditioners Temporary/Short-Term/Treatment Resilient Liners Permanent/Long-Term Resilient Liners Repair Resins Materials Denture Teeth Materials Custom Tray Materials Undesirable Properties of PMMA Denture Base Materials Porosities Crazing Fracture Resistance Polymerization Shrinkage Radiolucency Biocompatibility Hypersensitivity Microbial Growth Resins with Enhanced Properties and Applications Reinforced Denture Base Resins Primers for Enhancing Metal– Polymer Adhesion Soft/Flexible Dentures Radiopaque Resins Bisphenol A Glycidyl Methacrylate (Bis-GMA) Resins Hydron (Hydrogels) Polycarbonates Border Molding Material Mouth Guard Materials Splints Maxillofacial Materials Objectives of Maxillofacial Prosthesis Ideal Requisites of Maxillofacial Materials Classification of Maxillofacial Materials Materials Used Denture Cleansers Classification Immersion Denture Cleansers Infection Control for PMMA Denture Bases

168 169 169 169 170 170 171 172 172 172 173 176 176 176 178 179 179 179 179 180 180 180 180 182 183 184 184 184 184 184 184 184 185 186 186 186 186 190 190 190 190

Detailed Table of Contents

Sterilization Disinfection Conclusion

Dental Amalgam History Classification of Dental Amalgam (Adapted from Marzouk, 1997) Components of Dental Amalgam Silver Tin Copper Zinc Noble Metals Composition of Alloys Low Copper Alloys (G.V. Black’s Silver–Tin Alloy or Conventional Amalgam Alloys) High Copper Amalgam Alloys (Copper-Enriched Alloys) Zinc-Containing Alloys Manufacture of Alloy Powder Lathe-Cut Filings Spherical/Spheroidal/Atomized Powder Particle Size Amalgamation Reaction/Setting Reaction Symbols and Stoichiometry Low Copper Conventional Amalgam Alloys High Copper Admixed Alloys High Copper Single Compositional Alloys Elimination of g2 Phase Properties Strength Dimensional Changes Creep and Flow Tarnish and Corrosion Self-Sealing Ability of Amalgam Clinical Considerations of Dental Amalgam Selection of Alloys Mode of Supply Proportioning Dispensing of Alloy and Mercury

190 190 191

195 196 198 198 198 199 199 199 199 199

199 199 200 200 200 201 201 201 201 201 203 203 204 204 204 206 207 208 209 209 209 209 209 211

xxi

Trituration Mulling Undertriturated Mix, Normal Mix, and Overtriturated Mix Condensation Pre-Carve Burnishing Carving Post-Carve Burnishing Finishing and Polishing Quality of Dental Amalgam Factors Under Control of the Manufacturer Factors Under Control of the Operator Failure of Amalgam Restorations Reasons for Failure of Amalgam Restorations Uses of Silver Amalgam Gallium Alloys Bonded Amalgam Restorations Amalgam Bonding Agents Conclusion

219 219 220 220 220 221

Mercury

222

Properties Manufacture of Mercury Chemical Forms of Mercury Concentration of Mercury Mercury Toxicity Mercury Exposure in Dentistry Sources of Mercury Exposure in Dental O ce Mercury Allergy Symptoms of Chronic Mercury Exposure Mercury Hygiene Recommendations in Dentistry Management of Mercury Vapor Release in Dental O ce During Insertion of Amalgam During Amalgam Finishing and Polishing Procedures During Amalgam Removal During Instrument Sterilization Mercury Spills Recycling Scrap Amalgam Conclusion

222 223 223 223 223 224

228 228 228 228 228 229

Dental Cements

230

General Properties of Dental Cements Classification of Dental Cements

211 213 213 214 216 217 217 217 218 218 218 219

224 224 225 226 227 227

231 232

xxii

Detailed Table of Contents

Liners, Bases, and Sub-Bases Cavity Liners Cavity Bases Sub-Bases Luting Cements Temporary Restorations Interim Restorations Water-Based Cements Silicate Cement Zinc Phosphate Cement Copper Phosphate Cement Zinc Polycarboxylate Cement Zinc Oxide Eugenol Cement Modifications of Zinc Oxide Eugenol Cement Noneugenol Cements Calcium Hydroxide Cements Mechanism of Action Available Forms Silicophosphate Cement Glass Ionomer Cement Resin Luting Cements Composition Manipulation Compomer Mineral Trioxide Aggregate Types Composition Setting Reaction Properties and Mechanism of Action Clinical Applications Some Uses of MTA as Dental Cement Conclusion

232 233 235 236 236 238 238 238 238 240 244 245 247 250 251 251 251 251 252 252 253 253 253 254 254 254 254 255 255 255 255 255

Glass Ionomer Cements

257

Conventional Glass Ionomer Cements Composition Mode of Supply Setting Reaction Mechanism of Adhesion Types Properties Modifications of Glass Ionomer Cements Highly Viscous Glass Ionomers Metal-Modified Glass Ionomers Resin-Modified Glass Ionomers Compomers Clinical Considerations of Glass Ionomer Cements

257 257 259 259 262 263 263 265 265 266 267 269 270

Commercial Mode of Supply Manipulation Tooth Preparation and Restoration Durability of Glass Ionomer Restorations Conclusion

270 270 272

Composite Resins

275

History General Applications of Composites in Dentistry Composition Resin Matrix Fillers Coupling Agent Activator-Initiator-Accelerator Systems Other Components Polymerization Reaction Curing Lights Oxygen Inhibition Depth of Cure Degree of Conversion Modes of Curing Classification of Composites Traditional Composite Resins Based on Filler Particle Size Distribution Properties of the Composites Physical Properties Mechanical Properties Posterior Composites Nanocomposites Composites for Special Applications Packable Composites Flowable Composites Clinical Considerations Manipulation of Composite Resins Placement of Composites Configuration Factor (C-Factor) Postoperative Sensitivity Finishing and Polishing of Composites Repair of Composite Resin Restorations Bonding of Composite to Alloys and Ceramics Failure of Composite Restorations Conclusion

276

Direct Filling Gold

306

Characteristics of Gold as a Restorative Material Fineness and Purity of Gold

307 308

273 274

277 277 277 278 280 280 281 282 282 284 284 286 286 286 288 289 289 295 296 297 297 297 297 298 298 299 301 302 302 302 303 303 304

Detailed Table of Contents

Application of Gold in Operative Dentistry 308 Classification (Based on the Mode of Supply) 309 Physical Properties of DFG 309 Manufacture of Gold for Restorative Purposes 310 Gold Foil 310 Varieties of Gold for Restorative Purposes 310 Fibrous Gold/Gold Foil 310 Crystalline Gold 312 Other Types of Gold Foil 312 Supply of Gold Foils 312 Annealing/Degassing of Gold Foil 314 Alcohol Flame 314 Bulk Annealing 315 Condensation/Compaction of DFG 315 Objectives of Condensation 315 Rationale of Condensing Gold Foil 316 Factors Influencing Condensation of DFG 317 Technique of Compaction/Condensation of DFG 317 Clinical Considerations 318 Cavity Preparation 318 Use of Liners and Bases 318 Gold Placement and Condensation 318 Conclusion 320

Dental Casting Alloys

325

History of Metals in Dentistry Ideal Properties of Dental Casting Alloys Composition of Dental Casting Alloys Noble Metal Alloys Classification of Noble Metal Alloys Metal– Ceramic Alloys for Porcelain Bonding Base Metal Alloys Nickel– Chromium Alloy Cobalt– Chromium Alloy Titanium Alloys Longevity of Bonding of Metals to Ceramic/Porcelain Surface Oxide Layer Melting Range of Alloys T ermal Compatibility

326 326 329 329 330 331 334 334 335 335 336 336 336 337

xxiii

Clinical Selection of Alloys Conclusion

337 337

Dental Ceramics

339

Porcelain or Ceramics History Basic Procedure in Firing of a Ceramic Material Classification of Dental Ceramics Clinical Applications of Ceramics Composition Basic Oxides Additional Oxides Fluxes Opacifiers Pigments Ceramics for Ceramometal Restorations Requirements of a Metal– Ceramic System Conventional Feldspathic Porcelain Bonding of Ceramic to Metal Methods of Strengthening Ceramics Development of Residual Stresses Within the Surface of the Material Interruption of Crack Propagation All-Ceramic Materials/Systems Ceramics Based on T eir Microstructural Phase Ceramics Based on T eir Processing Technique Fabrication of Ceramic Prosthesis Conventional Powder/Liquid System Pressable/Cast Ceramic Restorations Zirconia Core/Ceramic Buildup Selection Criteria for Dental Ceramics Longevity of Ceramic Restoration Conclusion

340 340 341 343 343 343 344 344 344 345 345 345 346 346 349 350 351 352 353 354 358 361 361 365 367 367 369 370

Indirect Composite Resins

371

Need for IRC Restorations Porcelain Versus Indirect Composite Restorations Classification of IRC First-Generation IRC Materials Direct– Indirect Method Indirect Method Properties Second-Generation IRC Materials Properties

371 373 373 373 374 374 374 374 374

xxiv

Detailed Table of Contents

Improvements in Polymerization Techniques Nitrogen Atmosphere Soft Start or Slow Curing Electron Beam Irradiation Processing Mechanism Fiber Reinforcement Clinical Considerations Conclusion

375 375 375 375 379 379 379 381

Dental Implant Biomaterials

382

History Osseointegration Parts of an Implant Classification of Dental Implants Steps in Surgical Implant Placement Single-Stage Implants Two-Stage Implants Materials Used for Dental Implants Titanium and Its Alloys Iron-Chromium-Nickel– Based Alloys: Stainless Steel Cobalt-Chromium-Molybdenum Alloy Ceramics Polymers Surface Characteristics of an Implant Roughness Ultrastructural Characterization Nanotechnology in Implants Conclusion

382 383 384 385 386 386 386 389 389 389 389 389 390 391 391 393 394 394

Classification Based on Treatment of the Smear Layer Conclusion

Impression Materials and Techniques History Ideal Requirements of Impression Materials Guidelines for a Good Impression Classification of Impression Materials Inelastic Impression Materials Impression Plaster Impression Waxes Impression Compound Zinc Oxide Eugenol Impression Paste Elastic Impression Materials Hydrocolloid Impression Materials Nonaqueous Elastomeric Impression Materials Steps in Impression Making with Elastomers Impression Techniques Disinfection of Elastomeric Impressions Preparation of Custom Tray Fabrication Technique Functional Impression Materials Conclusion

Gypsum and Die Materials Recommended Properties of Model and Die Materials Materials Used for Making Models, Casts, and Dies Gypsum (CaSO 4 2H 2O) Uses of Gypsum Gypsum Products (CaSO 4 ½H 2O) Modifications of Gypsum Materials Used in Fabrication of Die Type IV and Type V Gypsum Other Materials Used in Fabrication of Dental Die Die Spacers Conclusion

411 414

415 415 417 417 418 418 418 420 423 427 430 431 441 452 452 454 455 456 457 458

461 461

Bonding and Bonding Agents

397

Development of Adhesives Enamel Bonding Dentin Bonding Classification of Bonding Agents First-Generation Bonding Agents Second-Generation Bonding Agents T ird-Generation Bonding Agents Fourth-Generation Bonding Agents Fifth-Generation Bonding Agents Sixth-Generation Bonding Agents Seventh-Generation Bonding Agents Current Classification of Bonding Agents Classification Based on Adhesion Strategy

397 398 399 399 399 399 399 401 405 407 409 410

Dental Waxes

483

411

History Uses of Waxes in Dentistry

484 485

462 462 462 463 479 480 480 480 481 482

Detailed Table of Contents

Classification of Waxes Composition of Waxes Individual Component Waxes Para n Wax Beeswax Carnauba Wax Microcrystalline Waxes Gum Dammar Synthetic Waxes and Resins Other Waxes Properties of Waxes Mechanical Properties T ermal Properties and Dimensional Changes Rheological Properties Inlay Wax Ideal Requirements Manipulation Properties Casting Wax Composition Properties Uses Baseplate Wax or Modeling Wax Ideal Requirements of Baseplate Wax Composition Types Uses Sticky Wax Composition Properties Uses Utility Wax Composition Properties and Indication Disclosing Wax Boxing Wax Composition Properties and Indication Low-Fusing Impression Wax Composition Properties and Indication Corrective Impression Wax (Korecta Wax, Iowa Wax) Composition Properties and Indication Bite Registration Wax Composition Steps of Bite Registration Conclusion

485 485 486 486 486 486 486 487 487 487 487 487 487 489 489 489 489 493 494 494 494 494 495 495 495 495 496 496 496 496 496 497 497 497 497 497 497 498 498 498 498 498 498 498 498 498 498 498

Investment Materials and Techniques

xxv

500

Investing and Investment Material Ideal Requirements of an Investment Material Components of an Investment Material Types/Classification of Investment Materials Setting Expansion of Investment Material Normal Setting Expansion Hygroscopic Expansion (Low Heat Technique) T ermal Expansion (High Heat Technique) Gypsum-/Calcium Sulfate-Bonded Investment Composition Chemistry of Setting Setting Time Expansion Phosphate-Bonded Investments Composition Chemistry of Setting Setting Time Expansion Ethyl Silicate-Bonded Investment Composition Chemistry of Setting Expansion General Criteria for Selection of Investment Materials Strength of Investment Material Accuracy of Investment Material Composition of Investment Material Applications of Investment Materials Brazing Investments Investing Procedures Sprue Former/Sprue Materials Used Dimensions of a Sprue Former Venting Investing the Wax Pattern Treatment of the Wax Pattern Investing Controlled Water-Added Technique Conclusion

501

512 512 512 512 513 513 513 514 514 514 515 515 518 518 519 519

Casting Procedures

521

Wax Burnout Preparation of Ring Before Placement

521 522

501 502 502 502 503 503 503 503 503 505 505 505 508 508 509 510 510 510 511 511 511

xxvi

Detailed Table of Contents

Placement of Ring in Burnout Furnace Wax Elimination Two-Stage Burnout Procedure Time Lapse Between Burnout and Casting Casting Crucibles Melting of the Alloy Flame Parts of the Flame Casting Machines Types of Casting Machines Divesting Noble Alloys Palladium-Based Alloys and Base Metal Alloys Inspection and Finishing of the Casting Laws of Casting Casting Defects Distortion Surface Discoloration, Irregularities, and Roughness Incomplete Castings Porosity Other Casting Defects Conclusion

522 523 523 524 524 524 525 526 526 526 527 527

Modification of the Abrasive Instrument Truing and Dressing Procedure Polishing Health Hazards During Finishing and Polishing Finishing and Polishing Procedures for Acrylic Dentures Finishing and Polishing Procedures for Restorations Amalgam Composite Resin Cast Metals Ceramics Conclusion

550 550 550

Antiplaque Agents

563

History Preventive Periodontal T erapy Primary Prevention Secondary Prevention Tertiary Prevention Dental Plaque as a Biofilm Structure and Properties of Biofilm Communities Plaque Concept—From Gingivitis to Periodontitis Clinical Importance Ideal Properties of Antiplaque Agents Mechanical Plaque Control Toothbrushes Detergents/Toothpaste Interdental Aids Oral Irrigation Devices Chemical Plaque Control Rationale for the Use of Chemical Mouth Rinses in Plaque Control Classification of Antiplaque Agents Some Antiplaque Agents Supragingival Plaque Control Subgingival Plaque Control Conclusion

564 564 564 564 565 565

550 552 552 552 552 554 556 560

528 528 528 532 532 533 534 535 536 538

Finishing and Polishing

539

Objectives of Finishing and Polishing Rationale for Smooth Surface of Restoration Rationale for Finishing and Polishing Terminology Associated with Finishing and Polishing Abrasion Hardness and Durability Factors Determining Finishing and Polishing Procedures Steps in Finishing and Polishing Speeds Used in Finishing and Polishing Instruments and T eir Designs Abrasive Instrument Design Abrasive Motion Bonded Abrasives Carbide Compounds Diamond Finishing Points Dental Stones Coated Abrasive Disks and Strips Abrasive-Impregnated Brushes and Felt Devices Nonbonded Abrasives

540 540 541 541 541 542 542 543 544 545 545 545 546 546 547 548 548 549 549

Materials Used for Remineralization Demineralization and Remineralization

565 566 567 567 567 567 568 569 571 571 572 572 572 572 577 579

581 581

Detailed Table of Contents

Ideal Requirements of Remineralization Agents Traditional Techniques in Remineralization Fluorides Systemic Fluoridation Topical Fluorides Sodium Fluoride Stannous Fluoride Acidulated Phosphate Fluoride Amine Fluorides Contemporary Techniques CPP-ACP (Recaldent™, GC Tooth Mousse™, MI Paste™) CPP-ACFP (GC Tooth Mousse Plus™) Beta Tricalcium Phosphate (Clinpro™ Tooth Crème) NovaMin™ Pronamel Enamelon™ Xylitol Conclusion

xxvii

582 583 583 583 584 585 586 587 587 589

589 590 590 590 591 591 591 591

Pit and Fissure Sealants

593

History Pit and Fissure Morphology Types of Fissures Ideal Requirements of Pit and Fissure Sealants Classification of Pit and Fissure Sealants Mode of Action Factors Responsible for Retention of Sealants Sealant Placement: Indications and Contraindications Clinical Applications Placement Techniques Procedure for Application of a Light-Cured Sealant Procedure for Application of a Chemically Cured Sealant Failure of Pit and Fissure Sealant Restorations Extended Fissure Sealing (Fissure Blocking) Preventive Resin Restoration Conclusion

594 594 595 596 596 598 598

Soldering and Welding

607

Soldering History Types of Soldering Components of a Soldered Joint Steps in Soldering Factors Leading to Failure of a Soldered Joint Clinical Applications of Soldering in Orthodontics Newer Developments in Soldering Welding History Types of Welding Principle of Orthodontic Welding Steps in Welding Failures in Welding Clinical Applications Conclusion

607 608 608 608 613

Orthodontic Material Science

621

Metals Stainless Steel Chrome– Cobalt Alloy Titanium and Its Alloys Gold Nonmetals Ceramics Plastics Futuristic Archwires Elastomers Conclusion

623 623 627 629 635 636 636 638 639 639 641

614 615 616 617 617 617 617 618 619 619 620

599 601 601 601 601 601 601 603 604

Root Canal Irrigants Purpose of Irrigation Factors Influencing the E cacy of Irrigants Classification of Irrigants Irrigants Distilled Water, Anesthetic Solutions, and Normal Sterile Saline Hydrogen Peroxide

645 645 646 647 648 648 648

xxviii

Detailed Table of Contents

Chlorhexidine Sodium Hypochlorite Combination Irrigation with Sodium Hypochlorite and Other Irrigants MTAD (Mixture of Tetracycline, Acid, and Detergent) EDTA (Ethylene Diamine Tetra Acetic Acid) Electrochemically Activated Water Iodine Potassium Iodide Clinical Procedure of Irrigation Conclusion

649 650

650 652 653 653 654 654 655

Intracanal Medicaments

656

Ideal Requirements of an ICM Classification of ICMs Phenolic Agents Phenol Camphorated Phenol Camphorated Monochlorophenol (CMCP) Cresatin Mixture T ymol Halogens Iodine Compounds Chloramine T Iodine– Potassium Iodide Sodium Hypochlorite Nonphenolic Biocides Aldehydes Biguanides—Chlorhexidine Digluconate Quaternary Ammonium Compounds Calcium Hydroxide Limitations of Calcium Hydroxide Corticosteroids Antibiotics Rationale for Use as ICM Clinical Considerations Technique of ICM Placement Conclusion

657 657 657 657 658 658 658 658 659 659 659 659 659 660 660 660 661 661 661 662 663 663 663 664 664

Calcium Hydroxide

666

Manufacture of Calcium Hydroxide Mode of Action Healing with High pH (11– 13) Calcium Hydroxide

667 667 667

Healing with Low pH (9– 10) Calcium Hydroxide Properties Strength Modulus of Elasticity Solubility, Disintegration, and Microleakage T ermal Insulation Biological Reaction Biological Properties Classification Applications of Calcium Hydroxide Calcium Hydroxide in Vital Pulp T erapy Calcium Hydroxide in Pulpotomy Calcium Hydroxide in Apexification Calcium Hydroxide as an Intracanal Medicament Other Applications of Calcium Hydroxide Conclusion

670 670 670 670 670 670 670 670 672 673 674 675 675 675 678 679

Root Canal Sealers

680

Ideal Requirements of Root Canal Sealer Functions of a Sealer Classification Composition Zinc-Oxide– Based Sealer Eugenol-Containing Sealers Non– Eugenol-Containing Sealers Iodoform-Based Sealers Iodoform Paste Calcium-Hydroxide– Based Sealers Calciobiotic Root Canal Sealer Sealapex Apexit ® Plus Vitapex® Polyacrylic-Acid– Based Sealer Polycarboxylate Cement Glass Ionomer Sealers Resin-Based Sealers Polyvinyl-Resin– Based Sealer Epoxy-Based Resin Sealers Methacrylate-Based Sealers Silicone-Based Root Canal Sealers Endofill RoekoSeal GuttaFlow®

680 681 681 681 681 682 687 687 687 688 688 688 688 688 688 688 689 689 689 689 690 693 693 693 693

Detailed Table of Contents

Clinical Considerations for Choosing a Sealer Conclusion

Materials Used for Obturation Ideal Requirements of Obturation Material Classification Metal Obturating Material Silver Points Plastic Obturating Materials Gutta-Percha Resilon Paste Filling Materials Iodoform Biocalex N2 (RC2B) Mineral Trioxide Aggregate Pediatric Obturation Materials Zinc Oxide Eugenol Iodoform Paste Calcium Hydroxide Materials Used in Removal of Gutta-Percha Chloroform (CHCl3) Eucalyptol (C10H 18O) Xylene Halothane Rectified Turpentine Orange Wood Oil Conclusion

Retrograde Filling Materials Ideal Requirements of a Root-End Filling Material Classification of Retrograde Materials Metals and Alloys Silver Amalgam Alloy Other Metals Cements Zinc-Oxide-Eugenol– Based Cements Glass Ionomer Cement Mineral Trioxide Aggregate Calcium-Enriched Mixture Calcium Phosphate Cement Resins Composite Resins Compomers

694 694

695 695 695 696 696 696 696 702 702 702 703 703 703 704 705 705 705 705 706 706 706 706 707 707 707

708

Diaket Epoxy-Resin– Based Materials Polymethylmethacrylate Bone Cement Castor Oil Polymer Conclusion

Materials Used for Tooth Whitening History Ideal Requirements of Bleaching Materials Factors A ecting the Rate of Color Change E ects of Bleaching Materials on Oral Tissues Common Bleaching Materials Hydrogen Peroxide Carbamide Peroxide Sodium Perborate McInnes Solution Types of Bleaching Procedures Vital Bleaching Nonvital Bleaching Clinical Assessment of Tooth Whitening Facts and Prognosis of Bleaching Precautions When Using Bleaching Materials Methods to Overcome the Complications/Drawbacks of Bleaching Conclusion

xxix

721 721 722 722 723

724 724 725 725 726 726 726 727 728 728 730 730 733 734 734 734

735 735

708 709 709 709 710 710

Local Anesthetic Agents

739

710 712 712 719 719 720 720 720

History Physiology of Pain and LA Local Anesthesia—Indications Local Anesthetic Armamentarium Features of an Ideal Anesthetic Composition of LA Solutions Classification of LA Agents T eories of LA Action Chemistry of LA Agents

740 740 741 741 741 742 742 744 746

xxx

Detailed Table of Contents

Physical Properties of LA Agents pH of LA Solution Concentration pKa Lipid Solubility Protein Binding Nonnervous Tissue Di usibility Vasodilator Action Biotransformation Excretion E ects of LA on Systems Local E ects Systemic E ects Contraindications of Local Anesthesia Absolute Contraindication Relative Contraindication Dosage of Local Anesthesia Calculation of Dosage Factors A ecting Dosage Local Anesthetic Overdose Vasoconstrictors Clinical Significance Chemistry Source Classification Dose Availability Contraindications Clinical Actions Anesthetics for Topical Application Chemistry Concentration Toxicity Duration of Application Depth of Anesthesia Forms of Topical Anesthetics EMLA LA Toxicity—Antidote Reversal of Cardiomyotoxicity Reversal of Soft Tissue Anesthesia Clinically Relevant Points Conclusion

746 746 747 747 747 747 747 748 748 748 748 748 749 750 750 750 751 751 751 752 752 752 752 754 754 755 755 755 755 756 756 756 757 757 757 757 757 757 757 758 758 758

Suture Materials

760

Wound Healing Healing by Primary Intention Healing by Secondary Intention Rationale for Suturing Suturing Armamentarium

761 762 763 763 763

History Ideal Requirements of Suture Materials Suture Size USP System EP System Brown and Sharpe Gauge E ect of Suture Size on Clinical Outcome Types of Suture Materials Based on the Source of Material Based on Degradability/Absorbability Based on the Number of Filaments Composition Basis of Suture Selection Common Suture Materials Suture Removal Tissue Response to Suture Materials Innovations in Suturing Technology Surgical Staples Surgical Tapes Adhesive Strips Fibrin Sealant Skin Adhesives/Cyanoacrylates Conclusion

771 771 771 773 774 774 775 775 775 775 775 776 777

Biomaterials Used in Periodontology

778

Biomaterials Used in Periodontal and Implant Surgery Regeneration Bone Replacement Grafts Mechanisms of Bone Regeneration and Augmentation Types of Graft Materials Membranes Used in Guided Tissue and Guided Bone Regenerations Objectives Functions of a Membrane Materials Used for Barrier Membrane Techniques Classification Nonresorbable Membranes Resorbable Membranes Materials Used for Root Coverage Acellular Dermal Allografts Laminar Bone Membranes Freeze-Dried Dura Mater

764 765 766 766 767 768 768 769 769 770

779 779 779 779 780 783 784 784 784 785 785 786 787 787 789 789

Detailed Table of Contents

Oxidized Cellulose Mesh Root Surface Biomodification Materials Socket Preservation Materials Cyanoacrylates Local Drug Delivery Systems Locally Delivered Drugs Used in Periodontology Periodontal Dressings Types of Dressings

789 789 790 790 790 790 792 792

Application of a Periodontal Dressing Periodontal Splints Types of Splints Gum Veneers Conclusion

Bibliography Index

xxxi

793 793 794 796 797

799 809

S ECTION

I

Fu n d a m e n ta ls o f De n ta l Ma te ria ls

Ma h a la xm i S . • Ka rth ike ya n K. • S rin iva s a n N. • Sa thya ku m a r S . • Ka vith a Sa n je e v • Po n s e ka r Ab ra h a m A. • Ve n ka t R.

Chapter 1

Introduction to Dental Materials

3

Chapter 2

Structure of Matter

8

Chapter 3

Properties of Dental Materials

19

Chapter 4

Light and Color

42

Chapter 5

Metals and Alloys

63

Chapter 6

Tarnish and Corrosion

77

Chapter 7

Principles of Adhesion

91

Chapter 8

Polymers in Dentistry

102

In tro d u ctio n to De n ta l Ma te ria ls CHAPTER

1

Chapter outline Historical Perspective Selection of Dental Materials Standards and Specifications for

Dental Materials Research Trends in Dental Materials Conclusion

Every tooth in a man’s head is more valuable than a diamond. Miguel de Cervantes, Don Quixote, 1605

Dentistry is an art and a branch of medical science that deals with the study, diagnosis, prevention, and treatment of diseases of the teeth, other parts of oral cavity, maxillofacial area, and the adjacent and associated structures. T ere are varieties of materials that are used in aiding each and every above-mentioned state. T e science of dental materials deals with the chemical composition, properties, manipulation, chemical reaction, mechanism of action, indications, contraindications, and clinical applications of the materials used in dentistry. Since any material placed in contact with the human body is termed biomaterial, most of the materials used in dentistry can be called biomaterials. Materials used in dentistry can be broadly categorized under two major groups: (a) materials that will remain in intimate contact with the oral tissues and (b) auxiliary materials that are used as an adjunct to the restorative materials and do not remain in direct contact with the oral structure.

Rome wa s not built in a day. John Heywood, 1497– 1580

T e evolution of dental materials started from various materials that had been used for other purposes. Either the same material or the concept that was used for other purposes was introduced into dentistry at di erent periods. For example, restorative materials have evolved over the decades from nonesthetic materials with mechanical adhesion to tooth-colored materials with chemical or micromechanical adhesion. T e thirst for attaining the ideal restorative material has led to constant evolution of materials and the associated technology. Materials such as gold, silver, lead, tin, platinum, and aluminum were used as restorative materials in di erent periods. Many of them were discontinued because of their drawbacks. Lead fillings became unpopular because of their softness (even before lead poisoning was understood).

4

Section I * Fundamentals of Dental Materials

Platinum was not used since it was too hard, inflexible, and di cult to form into foil. Aluminum failed because of its lack of malleability. In those days, restorations were made with metal foils rolled, condensed, shaped, and polished in the cavity. T e fillings were left slightly high so that the final condensation occurred on mastication. Gold foil, though being processed and filled through a laborious procedure, became popular since it did not corrode, was highly malleable and ductile, had excellent durability, and was safe. Tin and amalgam were also popular due to low cost but were held in low regard. Moreover, tin restorations oxidized easily and often warranted replacement. T e first dental amalgam alloy (1800—D’ Arcets mineral cement [France]) was composed of bismuth, lead, tin, and mercury; it was plasticized at 100°C. T e first room-temperature– mixed amalgam Bell’s putty was introduced in 1819. In 1833, the Crawcour brothers brought amalgam (Royal Mineral Succedaneum) to the United States. Amalgam has faced a lot of controversies; its use was restricted at various periods (Amalgam Wars I, II, and III). In 1843, the use of dental amalgam was declared to be a malpractice by the American Society of Dental Surgeons (ASDS). In 1845, this society also forced all of its members to sign a pledge to abstain from using mercury-containing fillings. T is was the beginning of the first dental amalgam war. T e war ended in 1856 with the rescission of the society. In the late 1800s, improved amalgams of Elisha Townsend, J.F. Flag, and G.V. Black were widely used. T ere has been a continued e ort on improving the properties, bonding, and esthetics of the restorative materials from time to time. During the first half of the twentieth century, silicates were the only tooth-colored esthetic materials available. Although silicates had good fluoride release, they are no longer used because they severely erode and easily discolor. Acrylic resins (polymethylmethacrylate [PMMA] based) replaced the silicates during the late 1940s because of their tooth-like appearance, insolubility in oral fluids, ease of manipulation, and low cost. But their

drawbacks included high coe cient of thermal expansion, high polymerization shrinkage, and lack of color stability. In 1955, Michael Buonocore introduced the concept of bonding acrylic resin to teeth by acid etching. In 1962, Dr. Raphael Bowen began experiments on reinforcing epoxy resin with filler particles. Wilson and Kent (1971) developed glass ionomer cement which bonds chemically with the tooth structure. Dentistry as a specialty is believed to have begun about 3000 bc . Modern dentistry began in 1728 after Pierre Fauchard published di erent treatment modalities describing many types of dental restorations, including a method for the construction of artificial dentures made from ivory. Gold shell crowns were described by Mouton in 1746. T e first porcelain tooth material was patented in 1789 by a French dentist de Chemant. In 1885, Logan patented porcelain fused to platinum post replacing the unsatisfactory wooden post previously used to build up intraradicular areas of teeth. T e first ceramic crowns were fabricated by Dr. Charles Land in 1903. T e lost wax technique has been used for centuries, but its use in dentistry was not common until W.H. Taggart introduced his technique with the casting machine in 1907. In 1959, the porcelain fused-to-metal technique was introduced. T e United States abandoned the gold standard in 1971. Gold then became a commodity freely traded in the open markets. In response to the increasing price of gold, the gold in the alloys was replaced by palladium and later by platinum. When the prices of all the noble metals further increased, base metal alloys such as Ni-Cr were introduced.

T e dentist must be aware of and understand the requirements, properties (biological and physical), performance, and applications of the dental materials. T e properties of the materials tend to di er in relationship to the type of use, the period of use in the oral cavity, the proximity

Chapter 1 * Introduction to Dental Materials

5

Dentist

Clinical requirements

Selection of dental material Based on

Physical properties

Biological properties and biocompatibility

Applications

Performance

Figure 1.1 Selection of dental materials.

of the material to the oral hard and soft tissues, etc. T e biocompatibility requirements also vary according to this. Nowadays, in most of the developed countries, all-ceramic restorations are preferred to metal–ceramic restorations. Even if metal ceramic is selected for a particular clinical situation, a noble metal (e.g., gold) is preferred to the base metal, since it has many advantages such as superior esthetics, better bonding, and unmatched biocompatibility. However, in spite of so many advantages of the ideal material of choice for the particular clinical situation, the next material in order is often used because of factors such as economy or the availability of the material. For example, the base metal is being used mostly for metal– ceramic restorations in developing countries. In some instances where the patient has metal (e.g., nickel) allergy, only all-ceramic or noble metal– ceramic restoration is indicated.

During the evolution of various dental materials, many studies were undertaken to understand their properties and e ects on oral tissues. It was di cult to compare the results of

di erent studies in several situations. T e dentists had di culty in choosing the right material for their clinical use. Hence, in order to standardize the testing protocols, the International Organization for Standardization (ISO) was formed. T e seed for standardization was sowed as early as the beginning of the twentieth century. Although there are many organizations that handle standardization of dental materials, most of the countries accept and follow only ANSI/ADA and ISO specification. T e American Dental Association (ADA) Seal of Acceptance program began in 1930. It has become an important symbol of a dental product’s safety and e ectiveness. ADA standards have been accredited by American National Standards Institute (ANSI) and thus they are designated as ANSI/ADA Standards. T ey also serve as the o cial United States representative for the International Organization for Standardization (ISO) Technical Committee 106 Dentistry (TC 106). T e ADA Standards Administration Department (DSA) manages two consensus bodies for development of standards, namely, the ADA Standards Committee on Dental Informatics (SCDI) and the ADA Standards Committee on Dental Products (SCDP). T is organization standardizes the properties of the materials—ideal requirements of material used for a particular application—and

6

Section I * Fundamentals of Dental Materials

New material

Physical properties Fulf lls ANSI/ADA or ISO specif cations Yes

No

Biocompatibility test

Rejected

Primary test Secondary test Usage test

Usage test: Improvement of the material to fulf ll specif cations

Education is a progressive discovery of our own ignorance. Will Durant

Wait for approval ANSI/ADA or ISO Accepted

them from the hazardous devices. T ese standardizations are reviewed regularly after a fixed time period or when there is a change in the concept or technology. T e various steps involved in the evolution of a new material from its introduction till its commercial availability are depicted in Figure 1.2.

Rejected

Comes to market with acceptance seal

Figure 1.2 Steps involved in the acceptance of a new material.

also develops newer materials, equipment, and testing methods. Before purchasing equipment, instruments, or materials, the dentist can consult the latest standards and reports issued by the ADA SCDP. T e present international standard is ISO, which began its standardization after the Federation Dentaire Internationale (FDI) requested ISO to consider its specification as ISO specification. T is led to the formation of International Organization for Standardization (ISO) Technical Committee 106 Dentistry (TC 106). Many countries (26) including the United States are the members of this committee, which is responsible for the standards in dental terminologies, specifications of dental materials, instruments, and equipment. T e Medical Devices Amendments law was formulated in 1976 for the welfare of public for protecting

It is also said that research is the first step to a journey of a thousand miles. Research starts with a simple word “why.” A research helps in the expansion or refinement of the past work in the field. T e principal purposes of basic research are discovery, interpretation, and documentation. Research in the medical field has always focused on three major aspects, namely, etiology, diagnosis, and treatment. In dentistry, much research is being conducted nowadays to compare and improve the properties, bond strength, and esthetics of dental restorations. T e body is capable of self-healing, tissue build-up, and reconstruction to a certain extent. But most of our body parts lost due to disease or accidents need to be replaced with prostheses to regain the lost form and function of the part. What about dental tissues? Enamel and dentin have building blocks similar to those of the bone, i.e., hydroxyapatite is the basic structural unit of bone, enamel, and dentin. But a bone, when fractured and adapted together, unites whereas enamel and dentin cannot repair on their own. T is may be due to the rich vasculature associated with the bone. It is better to preserve than to repair, better to repair than to restore, better to restore than to reconstruct. A.N. Didron, archaeologist, Bulletin Archeologique, Vol. 1, 1839

Chapter 1 * Introduction to Dental Materials

Tooth structures once lost can be replaced or repaired only with artificial materials that can mimic the tooth structure to a certain level. However, recent dental research is focused more on biomaterial science, especially on remineralization, stem cell therapy, revascularization/ regeneration, nanotechnology in dental science, improvements in bonding, etc., that may help in regeneration of dental hard and soft tissues.

An aching tooth is better out than in. To lose a rotting member is a gain.

7

Nowadays, these old statements do not hold true since progressive improvements have been made in material science and techniques. A teamwork of specialized dentists, general dentists, dental assistants, dental hygienists, and dental technicians is needed in providing good oral health services. A bad workman always blames his tools. It is mandatory that the associated dental personnels have adequate knowledge of the material science. T is not only enables them to select and handle the appropriate materials for the given clinical situation, but also ensures optimal properties of the material.

Richard Baxter, Poetical Fragments

Questions 1. Discuss the evolution of dental materials. 2. Enumerate and discuss various standards and specifications of dental materials. 3. Describe the various stages that every dental material undergoes before it comes to the market.

S tru ctu re o f Ma tte r CHAPTER

2

Chapter outline Atomic Structure: Fundamental Concepts Periodic Table Interatomic Bonding • Interatomic Primary Bonds • Interatomic Secondary Bonds

T e discipline of Dental Material Science involves investigation of the relationships that exist between the structures and properties of dental materials. T e structure of any material, including materials used in dentistry, usually reflects its individual components and their arrangement within the material. At the atomic level, the interaction between the di erent atoms, between electrons within the atoms and with other atoms, between the electrons and the nuclei, etc., all influence the basic structure of any material. T e interaction of electrons with the nuclei within the atoms only constitutes the subatomic structure. At an atomic level, the structure is made up of arrangement of atoms within the molecules and molecules with a component unit. At a microscopic level, groups of atoms or molecules agglomerate together forming a larger structure.

Bond Distance and Bond Energy States of Matter • Classical States • Nonclassical States Unit Cell Atomic Packing Factor Conclusion

T is can be observed under some type of microscope, hence termed microscopic. Finally, such microscopic structures together constitute the larger structural element that may be viewed with the naked eye and are termed macroscopic. To summarize, • • • •

Subatomic level: Interaction of electrons and nuclei within the atom Atomic level: Several atoms interact to form molecules Microscopic level: Several molecules group together to form microscopic structures Macroscopic level: T e structural component visible to the naked eye comprising many microscopic structures

When a material is subjected to external stimuli in any form—force, temperature, pressure, etc.—there

Chapter 2 * Structure of Matter

will be some form of response. For example, when force is applied to a material it will deform; heating a material changes its atomic position causing a change in its state. T e type and magnitude of a material’s response to a specific controlled stimulus constitute its properties. Generally, the properties of a material are independent of its shape and size. In addition to structure and properties, two other important aspects in the science of materials are manufacturing/processing and application/ performance. T ese four aspects of a material are interlinked since the structure of a material will depend on how it is processed. Moreover, its applications and performance in a situation will depend upon its properties. T us, the interrelationship among processing, structure, properties, and performance is linear. Why study atomic structure and interatomic bonding? A material’s properties can be better understood if its atomic arrangements and interatomic bonding is known. Some properties of solid materials depend upon the geometrical arrangements of the atoms and the type of interatomic bonding. Take for example carbon that exists in nature as both graphite and diamond. While graphite is relatively soft and has a “greasy” feel to it, diamond is the hardest known material. T is extreme di erence in the properties of both these forms of carbon can be directly attributed to the type of interatomic bonding found in them. T is chapter deals with several fundamental and important concepts such as the atomic structure, electron configurations of atoms, and the various types of primary and secondary interatomic bonds. A short description of the periodic table is also given.

It was not until the early twentieth century when an atom was considered as the basic building block of matter. History reveals that people in ancient times believed that all matter

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is a variation of earth, air, fire, and water. However, in the modern science era, it is known that atoms are made up of even more fundamental entities (protons and neutrons made of elementary particles known as quarks). Figure 2.1 depicts an increasing magnification of an ordinary matter down to an imaginary level. Each atom consists of protons, neutrons, and electrons. T e protons and neutrons are present in the nucleus at the center of the atom while the electrons revolve around the atom in what are known as orbits. Both electrons (negative) and protons (positive) are electrically charged while neutrons are electrically neutral. T e mass of protons (1.6726 × 10−27 kg) is 1836 times that of electrons while that of neutrons (1.6929 × 10−27) is 1839 times that of electrons; the mass of an electron is 9.109 × 10−31 kg. Each element is denoted by their atomic number (Z), which is the number of protons in the nucleus. In a neutral or complete atom, the number of electrons is the same as the atomic number. T is atomic number ranges in integral units from 1 for hydrogen to 118 for ununoctium, consisting of all elements, natural and synthesized. T e atomic mass (A) of a specific atom is expressed as the sum of the masses of protons and neutrons within the nucleus. T ough most of the atoms of a given element have the same number of protons, the number of neutrons may vary. Atoms with the same number of protons but di erent number of neutrons are known as isotopes. Since the atomic mass is constituted of the masses of protons and neutrons (electrons do not possess mass), isotopes have the same atomic number but di erent atomic masses. T e protons and neutrons are held together inside the nucleus by a strong internal force which is 6 × 1039 times more powerful than the gravitational force. T e electrons (negatively charged) are held in their respective orbits by the protons (positively charged). Valence electrons are the electrons in the outermost shell of the atom. T ey are typically the electrons which are involved in forming bonds to other atoms as opposed to the “core”

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Section I * Fundamentals of Dental Materials

Matter Macro: >10–8 m

Quark Subnano: 10–20 m Quark

Proton Subnano: