Edited by Theodore Eliades, DDS, MS, Dr Med Sci, PhD, DSc, FDS RCS(Ed) is Professor and Director of the Clinic of Orthodontics and Pediatric Dentistry, Director of Research, and Interim Director of the Institute of Oral Biology at the Center of Dental Medicine at University of Zurich in Switzerland. Christos Katsaros, DDS, Dr med dent, Dr hc, Odont Dr/PhD is Professor and Chair of the Department of Orthodontics and Dentofacial Orthopedics at the University of Bern in Switzerland.

• List of Contributors xiiiPreface xviiSection A Debonding 11 Cutting with Rotating Instruments and Cutting Efficiency of Burs 3María Arregui, Lluís Giner-Tarrida, Teresa Flores, Angélica Iglesias, and Andreu Puigdollers1.1 Introduction 31.2 Enamel Surface and Damage Associated with Debonding Techniques: Burs and Polishing 41.2.1 Design and Type of Burs 71.2.1.1 Diamond Burs 71.2.1.2 Tungsten Carbide Burs 81.2.2 Cutting Efficiency 101.2.2.1 Diamond and Carbide Burs 101.2.2.2 Rotating Instruments: Turbines and Electric Motor Handpieces 121.2.2.3 Other Factors Related to Cutting Efficiency 141.2.3 Effect of the Debonding Technique on the Enamel 161.3 Preservation and Remineralization 191.4 Clinical Considerations 20References 212 Debonding Protocols 28Eser Tüfekçi and William Brantley2.1 Introduction 282.2 Bond Failure Locations during Debonding 292.3 Protocols for Bracket Removal 302.4 Ultrasonic Debonding 332.5 Electrothermal Debonding 332.6 Use of Lasers for Debonding 342.7 Guidelines from Manufacturers 362.a Appendix: Units for Debonding Stress and Consideration of Debonding Force 37References 383 Bonding and Debonding Considerations in Orthodontic Patients Presenting Enamel Structural Defects 43Despina Koletsi, T. Gerald Bradley, and Katerina Kavvadia3.1 Introduction 433.2 General Considerations and Challenges of Bonding and Debonding Strategies 443.3 Enamel Structural Defects 473.3.1 Bonding/Debonding Considerations for AI Subtypes 503.3.2 Enamel Hypoplasia and Molar Incisor Hypomineralisation 523.3.3 Fluorosis 563.4 Concluding Remarks 58References 594 Enamel Colour, Roughness and Gloss Changes after Debonding 63Andreas Karamouzos, Effimia Koumpia, and Anastasios A. Zafeiriadis4.1 Introduction 634.2 Tooth Colour Changes Associated with Orthodontic Treatment 664.2.1 Colour Definitions – Vision and Specification 664.2.2 Tooth Optical Properties 684.2.3 Tooth Colour Measurement and Quantification Thresholds 694.2.4 Tooth Colour Changes Related to Orthodontic Treatment 704.2.5 Aetiology of Colour Changes 714.2.6 In Vitro vs. In Vivo Studies 724.2.7 ΔΕ and CIELAB Colour Parameter Changes 794.2.8 Long-Term Enamel Colour Changes 804.2.9 Types of Teeth 804.2.10 Gender and Age 814.2.11 Etching Pattern 814.2.12 Adhesives 824.2.13 Resin Removal Techniques 834.2.14 Quality Assessment of Studies 844.2.15 Conclusions 864.3 Tooth Bleaching Considerations After Debonding 874.4 Enamel Roughness Changes After Debonding 894.5 Tooth Gloss Changes After Debonding 94References 995 Aerosol Production during Resin Removal with Rotary Instruments 116Anthony J. Ireland, Christian J. Day, and Jonathan R. Sandy5.1 Introduction 1165.1.1 What Are Airborne Particulates, and Where Might They End Up? 1175.1.2 Why Do Airborne Particulates Present a Potential Health Risk? 1205.1.2.1 Aerodynamic Diameter and Lung Clearance 1215.1.2.2 Chemical Composition and Solubility 1225.1.2.3 Bioaerosols 1225.1.2.4 Dental Bioaerosols 1235.1.3 What Are the Occupational Health Risks? 1235.1.4 Are Dental Personnel at Risk from Particulate Inhalation? 1245.1.5 What Is the Evidence that Airborne Particulates Are Created during Orthodontic Appliance Removal with Rotary Instruments? 1255.1.6 What Are Workplace Exposure Limits (WELs), and How Do Particulates Produced During Orthodontic Debonding Compare with Them? 1295.1.7 What Methods Can Be Used to Reduce the Orthodontist’s Exposure to Airborne Particulates Produced During Appliance Debonding and Enamel Clean-Up? 1315.1.8 What about Bioaerosols Produced During Orthodontic Debond and Enamel Clean-Up? 1335.1.9 How Can the Risk of Inhalation of Dental Particulates during Orthodontic Debond and Enamel Clean-Up Be Minimised? 135References 1366 Evidence on Airborne Pathogen Management from Aerosol-Inducing Practices in Dentistry – How to Handle the Risk 143Despina Koletsi, Georgios N. Belibasakis, and Theodore Eliades6.1 Introduction 1436.2 Existing Evidence 1456.2.1 Existing Evidence from Synthesized Data Including Direct and Indirect Comparisons of Interventions 1546.2.2 Evidence Based on Single Study Estimates 1606.2.3 Quality and Confidence of Existing Evidence 1616.3 Findings in Context 1616.3.1 Use of Chlorhexine (CHX) as Pre-Procedural Mouth Rinse 1656.3.2 Alternative Effects and Actions of Povidone Iodine (PI), Ozone (OZ), and Chlorine Dioxide (ClO2) 1666.3.3 Aerosolized Pathogens and Dental Procedures 1686.3.4 Strengths and Limitations Stemming from Existing Evidence 1706.4 Concluding Remarks and Implications for Research 171References 1717 Future Material Development for Efficient Debonding 178Theodore Eliades7.1 Command-Debond Adhesives 1797.2 BPA-Free Monomers 1807.3 Biomimetic Adhesives 182Further Reading 1838 The Use of Attachments in Aligner Treatment: Analyzing the ‘Innovation’ of Expanding the Use of Acid Etching- Mediated Bonding of Composites to Enamel and Its Consequences 185Theodore Eliades, Spyridon N. Papageorgiou, and Anthony J. Ireland8.1 Enamel Involvement 1868.2 In Vivo-Induced Alterations of Aligners and Attachments 1888.3 Release of Compounds 1928.4 Debonding and Grinding 1948.4.1 Aerosol Hazards 1948.4.2 Xenoestrogenic Action (Bulk and Ground Particles) and Other Biologic Effects 1978.5 Concluding Remarks 198References 199Section B Fixed Retainer Bonding 2059 Composite Resins Used for Retainer Bonding 207Iosif Sifakakis9.1 Introduction 2079.2 Hardness 2089.3 Wear Resistance 2119.4 Bond Strength 2139.5 Microleakage 2159.6 Water Sorption 2199.7 Ageing 219References 22110 Wires Used in Fixed Retainers 227Iosif Sifakakis, Masahiro Iijima, and William Brantley10.1 Introduction 22710.2 Desirable Properties of Retainer Wires 23010.2.1 Stiffness 23010.2.2 Strength 23310.2.3 Range 23410.3 Clinical Selection of Retainer Wire 23610.4 Recent Research 241References 24211 Release of Bisphenol-A from Materials Used for Fixed Retainer Bonding 248Iosif Sifakakis11.1 Introduction 24811.2 BPA and Fixed Retainers – Clinical Considerations 25011.3 In Vitro Research 25211.4 BPA-Free Orthodontic Adhesives 25311.5 Conclusions 255References 25512 Clinical Effectiveness of Bonded Mandibular Fixed Retainers 259Thaleia Kouskoura, Dimitrios Kloukos, Pawel Pazera, and Christos Katsaros12.1 Introduction 25912.2 Short-Term Alignment Stabilisation 26012.3 Long-Term Alignment Stabilisation 26212.4 Failure Rates 26512.5 Periodontal Effects 26912.6 Side Effects of Fixed Retainers – Unwanted Tooth Movement 272References 27513 Masticatory Forces and Deformation of Fixed Retainers 283Iosif Sifakakis and Christoph Bourauel13.1 Introduction 28313.2 Clinical Observations 28313.3 Retainer Properties 28613.4 In Vitro Loading of Fixed Retainer Wires 288References 292Index 296