AN IN VITRO AND IN VIVO STUDY OF FLUORIDE UPTAKE BY DENTINE FOLLOWING APPLICATION OF VARIOUS TOPICAL FLUORIDE REGIMENS Nicola Jane Woodley A thesis submitted for the degree of Doctor of Philosophy in the Faculty of Dentistry University of London Departments of Biomaterials and Prosthetic Dentistry Eastman Dental Institute for Oral Health Care Sciences -1999- ProQuest Number: U641832 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest. ProQuest U641832 Published by ProQuest LLC(2015). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. Microform Edition © ProQuest LLC. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 ABSTRACT Restoration of severely worn dentitions frequently involves the use of overlay dentures. Such treatment can lead to the rapid development of caries. Topical fluoride regimens, including sodium fluoride, amine fluoride or stannous fluoride, have been used to reduce this risk. Sodium fluoride is regarded as effective but the other two compounds to be evaluated have benefits such as deposition of acid insoluble salts on the tooth surface. However stannous fluoride can be unstable and it has been suggested that amine fluoride/stannous fluoride combinations may be more effective. This study investigated the three fluoride containing compounds both alone and in combination to measure the effects on the fluoride content of dentine both in vitro and in vivo. The effect in vivo on caries incidence and on bacteria flora in plaque and saliva (Appendix 7) in patients wearing overlay dentures was also evaluated. Techniques for biopsy of dentine were assessed and a novel method was developed and evaluated for harvesting dentine in vitro and in vivo for fluoride analysis. The in vitro study examined the uptake of the three materials in paste and rinse, gel or solution. The results showed that all the regimens significantly increased the fluoride content of dentine except an amine fluoride/stannous fluoride (AmF/SnF:) gel. SEM analysis of the treated dentine surface showed deposition of solid material except following the AmF/SnF2 gel. The latter behaved inconsistently. This suggested that complexing of the fluoride ion might occur. The in vitro study also found that demineralised dentine took up fluoride ions but in this instance the AmF/SnF: gel produced a greater fluoride uptake. The in vivo investigation showed that in a double blind trial using patients wearing overlay dentures, biopsied dentine samples exhibited significantly increased fluoride levels following sodium fluoride and Amf/SnF 2 paste and rinse regimens. No statistical difference was apparent between the treatments. The use of the products in vivo resulted in a significant increase in new cavitated carious lesions in patients using the AmF/SnF2 regimen compared to the sodium fluoride regimen. The three monthly evaluation of plaque and saliva samples indicated no statistical difference in bacterial counts between the treatments. DECLARATION I hereby declare that the work embodied in this thesis is the result of my own investigations except where otherwise stated. The plating of plaque and saliva samples and counting of colony forming units that formed part of the investigation in Appendix 7 were carried out by Dr Tracy Burns and Mr Paul Bhuvanenthiran of the Department of Microbiology, Eastman Dental Institute for Oral Health Care Sciences, 256 Gray’s Inn Road, London. ACKNOWLEDGEMENTS I would like to thank Professor Gavin Pearson and Dr Brigitte Griffiths for their support, guidance and encouragement not only during the supervision of this thesis but over the last decade. You have been true mentors. Thank you also to Dr Bieri and his colleagues at GABA International Ltd. both for their financial sponsorship of this project and for their willing and rapid supply of information and materials. My gratitude for their generous advice and support goes also to: Professor Hubert Newman Professor Mike Wilson Dr Tracy Burns and Mr Paul Bhuvanenthiran - thank you for your patience and all your hard work My colleagues in the Biomaterials Department - especially Mr Ted Davies and Mr Graham Palmer My colleagues in the Prosthetics Department Finally, many, many thanks to Pamela, Jim and Caroline Woodley, Joanne Hill, Claire Price, Ruth, William and Alison Hooper and especially to David, Thomas, Robert and Sophie Hooper. I am truly grateful for your help and forbearance. INDEX OF CONTENTS ABSTRACT..........................................................................................................2 DECLARATION....................................................................................................3 ACKNOWLEDGEMENTS.................................................................................... 4 INDEX OF CONTENTS........................................................................................5 LIST OF FIGURES...............................................................................................9 LIST OF TABLES....................................... 11 STRUCTURE OF THESIS..................................................................................13 CHAPTER 1 LITERATURE REVIEW...................................................................................... 14 1. The Management of Tooth Wear with Removable Partial Dentures ................. 15 2. The Incidence of Caries in Patients Wearing Dentures to Restore Tooth WearlS 3. The Development of Topical Fluorides ...............................................................29 4. The Development of Amine Fluoride, Stabilised Stannous Fluoride and Amino- Stannous Fluoride Preparations........................................................................ 38 4.1 The Development of Amine Fluorides Preparations ........................................... 38 4.2 The Development of Stabilised Stannous Fluoride Preparations ......................42 4.3 The Development of Preparations Combining Amine and Stannous Fluorides. .................................................................................................................................44 5. The Anti-Caries Activity of Stannous Fluorides, Amine Fluorides and Amino- Stannous Fluoride Regimens ............................................................................ 46 5.1 Inhibition of Demineralisation ................................................................................ 46 5.2 Promotion of Remineralisation .............................................................................. 48 5.3 The Formation of Calcium Fluoride ...................................................................... 49 5.4 Promotion of Fluoride Uptake by Dental Mineralised Tissues ........................... 54 5.5 Surfactant Activity of Amine Fluorides ..................................................................59 5.6 Anti-Microbial Properties........................................................................................60 5.7 Caries Inhibition...................................................................................................... 72 6. The Measurement of Fluoride Content of Dental Mineralised Tissues ...............78 6.1 Techniques for Biopsy of Dental Mineralised Tissues ........................................78 6.2 Techniques for the Analysis of the Fluoride Content of Dental Mineralised Tissues................................................................................................................... 89 6.3 The Analysis of the Fluoride Content of Dentine .................................................96 6.4 Altemative Approaches to the Analysis of the Fluoride Content of Dental Mineralised Tissues............................................................................................. 96 7. Statement of the Problem ................................................................................... 97 8. Aims and Objectives ...........................................................................................9^ CHAPTER 2 MEASUREMENT OF THE FLUORIDE CONTENT OF DENTINE DEVELOPMENT OF METHOD.............................................................................. 100 1. Preparation and Storage of Teeth for In Vitro Investigations............................101 2. Biopsy Techniques........................................................................................... 103 2.1. An Evaluation of the Use of Trephines to Biopsy Dentine .......................................104 2.2. Evaluation of the Use of a Diamond Bur to Biopsy Dentine In vitro....................... 105 3. Methods of Fluoride Analysis...........................................................................109 3.1 Dissolution of Dentine in One Molar Hydrochloric Acid .......................................... 109 3.2 Analysis of Fluoride..................................................................................................... 112 4. Topical Fluoride Preparations ............... 116 5. Statistical Analysis............................................................................................ 122 CHAPTER 3 MEASUREMENT OF FLUORIDE UPTAKE BY DENTINE FOLLOWING TOPICAL FLUORIDE