Fluoride and the Tooth Surface PDF

Fluoride and the Tooth Surface Oral and Dental Science Josh Hudson GDC Learning Outcomes: 1.1.8 Describe the proper0es of relevant medicines and therapeu0c agents and discuss their applica0on to pa0ent management 1.10.2 Provide pa0ents with comprehensive and accurate preventa0ve educa0on...

Fluoride and the Tooth Surface Oral and Dental Science Josh Hudson GDC Learning Outcomes: 1.1.8 Describe the proper0es of relevant medicines and therapeu0c agents and discuss their applica0on to pa0ent management 1.10.2 Provide pa0ents with comprehensive and accurate preventa0ve educa0on and instruc0on in a manner which encourages self care and mo0va0on 1.10.3 Underpin all pa0ent care with a preventa0ve approach that contributes to the pa0ent's long-term oral health and general health 1.10.4 Advise on and apply a range of preventa0ve materials and treatment as appropriate 2.3 Describe and evaluate the role of health promo0on in terms of the changing environment, community and individual behaviours to deliver health gain 2.4 Explain evidence-based preven0on and apply appropriately  Pre-reading Caries ‘Ae0ology of Dental Caries’ Lecture Suscep@ble tooth surface Plaque Bacteria Time Fermentable Carbohydrate Pre-reading ‘Histology of enamel and den0ne’ Lectures Intended learning outcomes By the end of this session you will be able to.. List the key milestones in the history of Ouoride and its use in caries preven0on Outline and describe the stages in Ouoride deposi0on Describe the modes of ac0on of Ouoride Explain how Ouorosis occurs Iden0fy Ouorosis and assess its severity Refresher session… Normal enamel is mainly made up of hydroxyapa0te This makes up 96% of enamel This is made of a laWce structure It is primarily made of phosphate and calcium ions Ca10 (PO4)6 (OH)2 Refresher session.. Decreasing pH As pH lowers below the cri0cal pH (5.5 for hydroxyapa0te), the tooth surface will demineralise Ca 10 (PO4)6 (OH)2 and break down into its component ions. If the pH regularly remains low Demineralisa0on and does not neutralise, extensive demineralisa0on over 0me will lead to caries. Ca 2+ , PO4 3- + OH- (hydroxyl ion) Refresher session.. Infrequent a]acks mean less 0me below cri0cal PH and less demineralisa0on (lower caries Stephen Curves risk) Frequent a]acks mean more 0me below the cri0cal PH and hence more demineraliza0on (higher caries risk) How is Juoride relevant to you as dental professionals? Fluorine Before we can eaec0vely link Ouoride to den0stry, we need to understand what it actually is and its history.. Comes from element fluorine , combines with other elements to become fluoride. Fluorine  Has the symbol F and atomic number 9 Highly reac0ve Is a Halogen within with metals to the periodic table Fluorine form salts or halides (referred to as !uoride) Found naturally in water, rocks, soil and tea  1892 1901 Frederick McKay 1902 1874 Sir James Crichton-Browne Sale of Ouorine compound Dr Erhardt 1909 Inves0ga0on of Colorado Stain 1931 1930 Staining on teeth in Bauxite, Arkansas 1912 Dr HT Dean ‘shoe leather’/ ‘21 McKay inves0gates similar ci0es’ studies 1916 staining in Naples, Italy GV Black paper published on Colorado Stain 1945 1932 First experiment of ar0icial water McKay link between mo]ling Ouorida0on 1933 and caries reduc0on Ainsworth UK water Ouoride 1940 comparison studies 1955 Ar0icial water Ouorida0on tried out in the UK 1960 1964 An0-Ouoride Birmingham Ouoridated campaigns 1976 2000 The Royal College of Physicians‘ The York Study enquiry into water Ouorida0on 1980 Mrs McColl’s opposi0on 1985 of water Ouorida0on KNOX report The Future… Fluoride History 1. Colorado stain iden0ica0on 2. HV Churchill water tes0ng 07 01 7. Cochrane review 02 06 3. Iden0ica0on Ouoride may reduce caries 03 6. York report 05 04 4. Shoe leather surveys/21 ci0es surveys 5. Knox report 1) Colorado Stain - 1916 Dr Frederik McKay documented a ‘stain’ on some teeth when working in Colorado springs He was the irst to document this appearance and went on to inves0gate its cause Enlisted the help of GV Black to inves0gate GV Black published a paper on the Colorado Stain 2) Water Sampling - 1931 Following iden0ica0on of this stain by McKay, Churchill, who was a chemist for a local mining company in Arkansas, realised local children developed a similar eaect following their water source changing Concerned this may be linked to his companies aluminium mine, he inves0gated the water He iden0ied higher Ouoride content in water where mo]ling was present Advised although there is higher Ouoride in these areas, no deini0ve link to the mo]ling 3) Iden@Tca@on Fluoride may reduce caries - 1932 Although this had been postulated previously, in 1932 McKay suggested that the same compound that caused the mo]ling may reduce caries McKay had iden0ied although mo]led, these teeth developed no greater chance of decay that teeth which are normally calciied 4) Shoe leather studies/21 ci@es studies – 1930-1940 Following McKay’s claims, the head of the US public health service assigned Dr H Trendley- Dean to research the links between Ouoride in water, mo]ling and caries reduc0on. His subsequent studies demonstrated; Increased mo]ling with increased Ouoride Decreased caries if water Ouoridated 1ppm Ouoride appeared to be the op0mal level He developed an ‘Index for Fluorosis’ to classify the severity of this tooth mo]ling  Beneits discovered Water Fluoridated Caries reduc0on Campaigns against ‘mass medica0on’ 5) Knox Report - 1985 Review of papers looking at the links between Ouoride and cancer Concluded that there is no link and Ouoridated drinking water is safe 6) York Report - 2000 Reviewed evidence from hundreds of studies into water Ouorida0on No associa0on found between water Ouorida0on and bone fractures, or water Ouorida0on and cancer  Based on older research (no Fluorida0on increased the modern research percentage of children with no available) decay in deciduous teeth by 15% Insupcient evidence on eaect in adults 73% of studies focussed on areas with natural =uorida>on Cochrane Review 2015 Fluoridated water reduces caries in children's permanent Fluorida0on increased teeth by 26% the percentage of children with no decay in Fluorida0on of 0.7ppm gives permanent teeth by 14% a 12% chance of Fluorosis Fluoridated water reduces (mo]ling) that may cause caries in deciduous (baby) aesthe0c concerns teeth by 35% Modern Day Controversy s0ll remains for ar0icial water Ouorida0on Currently in the UK approximately 10% of the popula0on has Ouoride in the water Have you lived in an area with Ouoride in the water? Click this link to ind out Modern Day Luckily, although water Ouorida0on is not universal, the beneits of Ouoride use are well researched and well advocated in caries preven0on Cochrane Studies Delivering Be]er Oral Health NHS Website NHS Review of Water Fluorida0on Pa0ents will s0ll ques0on its use! So how does Juoride prevent caries? How does it work? - Uptake into the tooth Ingested fluoride Topical fluoride Pre-erup0ve Post-erup0ve Ul0mately, Ouoride is stage (systemic stage (topical absorbed into the tooth Juoride) Juoride) surface making it more resistant to demineralisa0on from the Matrix caries process. This occurs Secre0on at mul0ple stages; Matura0on Stage How is it absorbed? – Matrix Secre@on Stage Fluoride absorbed from systemic sources (swallowed Ouoride) Travels to developing tooth buds via blood and surrounding 0ssue Ouid Deposited into the tooth during enamel forma0on as Ouoroape0te This Ouoroape0te replaces the usual hydroxyape0te Excess Ouoride can inhibit ameloblast Motteling ac0vity aaec0ng enamel development This may result in ‘mo]ling’ termed Ouorosis  How is it absorbed? - Matura@on Stage Fluoride absorbed from systemic 1 sources (swallowed Juoride) Occurs acer calciTca@on but 2 prior to erup@on Deposi@on of Juoride con@nues at the 3 enamel surface from the @ssue Juid around the tooth 4 More Juoride is taken up by outer layer 5 Also forms Juoroape@te How is it absorbed? - Post-Erup@ve Stage Deminerlization Drop in PH due Loss of calcium and Healthy tooth to bacterial acid Demineralised phosphate from surface tooth surface hydroxyapa0te Addi0on of Increase in calcium and Remineralisa0on PH phosphate from saliva to reform hydroxyapa0te Reminerlization How is it absorbed? - Post-Erup@ve Stage Drop in PH due Loss of calcium and Healthy tooth to bacterial acid Demineralised phosphate from surface tooth surface hydroxyapa0te Addi0on of calcium Increase in and phosphate and Remineralisa0on PH Juoride from saliva to form Juoroape@te How is it absorbed? - Post-Erup@ve Stage Key Points The most Ouoride is acquired during the 2-3 years post-erup0on This is because it is more porous which facilitates diausion and uptake Demineralised enamel also absorbs Ouoride more easily for this reason Fluoride reacts strongly with calcium so does not penetrate deeply if used topically Maximum uptake cannot be exceeded but Ouoride can be replaced as the surface is abraded It is therefore more essen@al for Juoride to be used to reduce the progression of caries rather than purely prevent it. This is because it is more easily absorbed once the process has started. So it works by producing Juoroape@te but why is this important? Why is Juoroape@te important? Formed by Ouoride ions replacing hydroxyl ions during remineralisa0on This newly formed molecule is more stable due to improved hydrogen bonds, fewer imperfec0ons and larger crystals Helps inhibit demineralisa0on Fluoroapetite’s critical and promote remineralisa0on PH = 4.5 Why is Juoroape@te important? Due to the lower cri0cal PH, Ouoroape0te is less soluble. This makes the tooth more resistant to future acid a]acks This, therefore, reduces demineralisa0on This ul0mately reduces caries incidence Where does the Juoride come from? Toothpaste Topical applica0ons of Ouoride create a reservoir of Ouoride in saliva This Ouoride bonds to calcium in saliva forming CaF2 When an acid a]ack occurs and PH drops, the Ouoride is released This can then enter the tooth during remineralisa0on It is therefore essen@al that there is a regular supply of low-level Juoride to replace the ions lost. This forms the basis of caries preven@on with Juoride. Ways to ensure this regular supply is maintained are summarised here Topical Fluoride Source Fluoride Level Prescrip@on? Toothpaste (Stannous/Sodium 1450-5000ppm YES if 2800 or 5000ppm Fluoride) Mouth rinse 225ppm EITHER Restora0ve materials (e.g. Glass 0.8-1.2ppm dropping over - Ionomer Cements) 0me Fluoride Varnish 22,600ppm YES Water Fluorida0on 0.7-1ppm generally NO Fluoride Tablets Made up to 0.3-0.7ppm YES How does that work in real life?  Ca Fluoride present in saliva Ca Ca PH Ca DROP F Ca = Hydroxyapa0te Ca = Fluoroapa0te Ca  pH RISE F = Hydroxyapa0te = Fluoroapa0te Does Juoride have any other mechanisms of ac@on?  Bacteria H H H H H H Fluoride is taken in by bacteria and over time this becomes toxic H to bacteria H Ac@on on bacterial plaque At concentra0ons over 1% (such as professionally applied Ouoride), a bactericidal eaect is demonstrated This means Ouoride can be toxic to bacteria such as strep mutans When the PH drops, H+ and F- bond to form HF which then diauses across the bacterial cell wall This then inhibits glycolysis by preven0ng the uptake of glucose through the cell wall and its breakdown. It also inhibits enzyme systems involved in the conversion and transport of sugars This cuts of the bacteria’s food supply meaning it cannot metabolise sugars into acid F When fluoride present on teeth bacteria struggle to adhere to the toooth. Ac@on on enamel surface Fluoride reduces the surface It has also been energy of enamel. This has the 0 suggested that Ouoride eaect of decreasing the 03 on the tooth surface can we]ability of enamel and 1 ‘push away’ proteins hence ability for bacteria to which reduces pellicle adhere forma0on Less pellicle This prevents the forma0on, less forma0on of pellicle plaque and less so plaque cannot 02 04 bacterial adhesion accumulate as easily leads to a reduced likelihood of caries Ac@on on tooth morphology Some evidence suggests that systemic Ouoride 0 may alter tooth 1 morphology during their development These may 03 therefore make the tooth more cleansable This can result in; Shallower pits Reduced issure 02 depth Lower cusp height What about the other tooth surfaces? (Den@ne and Cementum) Root Caries Recap As these are Gingival recession mineralised surfaces, exposes den0ne and these are also cementum suscep0ble to decay This is root caries This is more common in; As they are less xerostomia pa0ents mineralised, decay can (pa0ents with limited progress saliva) and radiotherapy faster pa0ents  How does Juoride prevent root caries? 1. Incorpora0ng into surface during remineralisa0on 2. Reducing surface we]ability 3. An0bacterial eaects (Kato et al, 1997) What does the research say? Topical Fluoride to Prevent Root Caries: Systema@c Review with Network Meta-a nalysis Professionally applied Ouoride (Silver diamine Ouoride, Ouoride varnish) reduces risk of root caries at 2 years Self-applied Ouoride (various concentra0ons of sodium Ouoride mouth rinse, and Ouoride tooth paste) reduces risk of root caries at 1 year Therefore, professionally and self-applied Ouoride is essen0al for caries preven0on in pa0ents with exposed root surfaces (den0ne and cementum) at risk of caries. Will become more of an issue as the popula0on con0nues to age. Fluorosis What is Juorosis and how does it form? What is it? “The term given to changes in the enamel which are associated with excess inges0on of Ouoride…it can vary from white opaci0es, lines or Oecks to more severe brown-yellow mo]ling of the enamel. The precise eaect depends on the dose of Ouoride (from all sources), dura0on for which it was taken, and the age of the pa0ent at the 0me of inges0on.” Clinical Textbook of Dental Hygiene and Therapy (Edited by Robert Ireland, 2006) Mechanism of Juorosis If excess Ouoride is present it is thought to inhibit normal ameloblast ac0vity during the matrix forma0on and matura0on phases, and hypomineralised (and hypoplas0c) enamel will form. Due to the hypomineralisa0on, the enamel becomes more porous and hence more readily takes up stain which can cause more obvious discoloura0on. It is important to remember that enamel defects can result from other causes, not just Ouorosis. For example: trauma, disease, drugs and gene0cs. What are the ae@ological agents? The inges0on of the below can cause Ouorosis; 1. Dietary Juoride supplements 2. Drinking water 3. Toothpaste 4. Topical applica@ons The most cri0cal 0me is from 0-8 years as the teeth develop Due to the staggered nature of tooth development, not all teeth will always be aaected depending on the 0ming of the Ouoride exposure Is it Juorosis? Indices for recording Juorosis The two main indices are the Dean Index (1942) and the Thylstrup and Fejerskov index (1978) The Thylstrup and Fejerskov index is shown to the right Score 0 the enamel has normal translucency Scores 1-4 has increasing levels of Ouorosis with no loss of the outermost enamel Scores 5-9 has increasing degrees of loss of the outermost enamel Summary Summary Ac0on on hydroxyapa0te Ac0on on tooth Ac0on on bacterial Mode of Ac@on of Fluoride morphology enzymes Ac0on on enamel surface Summary h]ps://www.youtube.com/watch?v=TyVV0UDQ_f4 h]ps://www.youtube.com/watch?v=TyVV0UDQ_f4 Thank You!