1.DR. PAWAN SINSINWAR DEPARTMENT OF PEDIATRIC AND PREVENTIVE DENTISTRY

2. CONTENT Introduction Historical evolution of fluorides Fluoride chemistry and occurrence Total intake of fluoride From Air From Water From Food Fluoride metabolism and bioavailability Physiologic distribution of fluoride In blood and soft tissue In hard tissue 3. Excretion of fluoride Placental transfer of fluoride Water fluoridation School water fluoridation Fluoride tablets Fluoridated salt Fluoridated milk Fluoridated flour and sugar Toxicity of fluoride Defluoridation 4. HISTORY In 1805, Morichini found fluoride in human Enamel. Fluorine discovered by chemist Scheele in 1771- isolated by Moissan in 1886 First report of fluoride concentration in drinking water quoted in ppm given by Hillebrand. Desirabode in 1847 referred to fluates-(silicate or fluate of lime and alumine, dried and pulverized) First reference to prophylactic role of fluoride made by Erhadt in 1874 Fluoride pills (KF) recommended in England, comes in pleasant tasting form as hunter pills Dr A. Denninger (1896)- Fluoride an agent to combat dental disease and Appendicitis 5. In 1901 Dr. Federick Mckay- Colorodo Stains minute white flecks, yellow or brown spots scattered.. In 1902 Dr. J.M. Eager noticed in Italian emigrants -denti di chiaie 1916, Dr. Green supported Mckay work with histologic evidence an endemic imperfection of the enamel of the tooth In 1918 Dr. O. E. Martin and Mckay- Britton (1898) changed water supply from shallow wells to deep drilled artesian wells. 1931 Mr. H. V. Churchill- spectrographic analysis of Bauxite city water 13.7ppm 6. in 1933, Dr. H. Trendley Dean- conducted Shoe Leather Survey in 97 localities, with a aim to find out minimal threshold level. In 1939 came out with domestic water is primary cause of human mottled enamel ( dental fluorosis) In the same year- hypothesis showing inverse relationship between endemic fluorosis and dental caries 7. Fluoride chemistry & occurrence - Greek floris- destruction Latin fluor- flow or flux Symbol- F Atomic no.- 9 Atomic weight- 18.99 It is a pale yellow, corrosive gas, which reacts with practically all organic and inorganic substances Most electronegative of all elements 8. Reasons for high reactivity:- 1s2, 2s2, 2p5 Most electronegative of all elements Small size of atom High electron affinity Small bond length 9. 17th in order of abundance of all elements Constitutes about 0.032% in earths crust Fluoride containing minerals- Fluorspar (CaF2) - 48.8% Cryolite (Na3AlF6) rare Fluorapetite Ca10(PO4)6F2- 3.8% 10. Fluoride In Air HF or Gaseous F2 Dust of f2 containing soils, gaseous industrial, coal smoke, and volcanic emulsion. Levels of air borne- Aluminum factories: 5micro grams/ m3 11. Fluoride in plants Roots form soil and Leaves form air Camellia sinensis acidic soils, Indian Tea leaves 70 to 375 ppm Vegetables- factories- 10ppm Fruits and vegetables- 0.2 to 0.5 microgram/gram wet wt. grown near aluminums 12. Fluoride In Animal Products Beef, pork and mutton-0.3ppm Higher in Chicken- contamination bone and cartilage fragments Fish products- up to 20ppm Dried sea foods also fluoride rich 84.5ppm (South East Asia) 13. Fluoride In Beverages Ranges from 0.05 to 1.05 ppm Fluoride content in alcoholic beverages generally reflects that of water used. 14. Total daily intake of fluoride Fluoride from Air Minimal Fluoride from Water Most important single source of fluoride Dependent on fluoride concentration and amount Fluctuation climatic and geographical areas Fluoride from food 0.3 to 0.6 mg/day Fluoride intake 6months of life-bottle/breast fed Breast fed infant receives 0.003 to 0.004mg/day- formula fed infants (1.2ppm) fluoride intake increased 50 times 15. Excessive consumption of tea and sea foods- increased flr National Research Council 1980 safe and adequate 1.5 to 4.0 mg/day in adults 0.05 to 0.07 mg/day in children for optimal dental health Threshold level drinking water 2.0ppm- dental fluorosis 16. Fluoride metabolism & Bioavailability Therapeutic action and safety of fluoride kinetic process Mechanism and site of absorption:- Water soluble fluorides- NaF, HF, H2SiF6, Na2PO3F and StF Less soluble fluorides- CaF2 , Ca10(PO4)6F2 Passive in nature Rapid absorption stomach- nonionic diffusion of HF Ph of gastric fluid-free F in the form of HF With milk, F bioavailability decreased.. Formation of low soluble calcium fluoride Binding to casein and colloidal calcium phosphate Clotting of milk (acidity)-physical barrier over mucosal 17. Absorption from solid foods is less compare to liquid 80% of ingested is absorbed From fluoride preparation and dental materials:- Dentifrices- less Alginate (4450 to 24,240 ppm)- systemic absorption peak in 30 min Single impression Zelgan- 119ng/ml in plasma level Double impression -200ng/ml 150 ng/ml from 3mg F in aqueous solution Fluoridated anesthesia- halothane, Methoxyfluorane, Enflurane -630ng/ml 18. PHYSIOLOGIC DISTRIBUTION OF FLUORIDE Fluoride in Blood:- Blood plasma is most reliable indicator in plasma and in RBC Fluoride exists in both forms -bounded from -ionic form- varies concentration F in drinking water Increase in plasma F with age and in presence of renal failure Drinking water 0.25 or 1.25 ppm plasma level 0.01 or 0.025ppm Increased reactive sites and voids in old bone is more saturated and filled with F than young bone 19. Fluoride In Soft Tissue Tissue/ plasma ratio = 0.4 to 1 Ectopic calcification loci- F accumulation in Aorta, tendon, cartilage and placenta 20. Effects On Kidney Fluoride is normally cleared from the blood by deposition in bone, excretion in urine- unable to find toxic effect on kidney endemic fluorosis. Patients with chronic renal failure- dialysed with fluoridated have additional load of fluoride So fluoride free water is used for kidney dialysis 21. Bone:- Total amount-2.6mg Most of F in the body retained in the skeleton-vary according to the renal clearance F enter in mineralized tissue-replacing 0H-, C03 2- and HC03 - Remodeling bones deposit more fluoride than older people Fluoride deposition is a reversible process 22. Teeth:- Deposition occurs in successive stages. Initial deposition organic and mineral phases are laid down Pre-eruptive maturation phase-before eruption Post eruptive maturation and aging period Dentine contains 4 times more than enamel Fluoride concentration not uniform Fluoride concentration initial stages is higher than on completion ( mineralization process- release of F to the bathing fluid) Primary teeth less fluoride concentration than permanent teeth 23. Permanent teeth Primary teeth Non-fluoridated areas Fluoridated areas 1100ppm 2200ppm 670ppm 950ppm 24. F concentration in newly erupted teeth- higher in in incisal than cervical margin Diffusion of F in enamel NaF and monoflurophosphate(100pmm)- 10-9cm2/sec Speed at which F penetrates in enamel- 38 micrometer/ hour (186micrometer/ day) 25. Concentration in dentin:- more than enamel-apatite crystals are smaller -surface area and capacity to take is much larger In permanent teeth: Highest near the pulpal surface low in secondary dentin In primary teeth complicated physiologic resorption occurs towards pulpal side greatest rise and fall Pulpal surface of multirooted teeth 26. Fluoride concentration in Cementum:- Higher than any skeleton or dental tissue Tissue is very thin Near the tissue surface- accessible to fluoride present in blood Increases with age 27. Mechanism Of Action Of Fluoride In Caries Reduction. Increased enamel resistance (or) reduction in enamel solubility Increased rate of post eruptive maturation Remineralization of incipient lesions Interference with plaque microorganisms Modification in tooth morphology 28. Enamel Fluorosis Enamel mottling described by Eager in 1901 in Naples & Italy Black and Mckay In 1916 in Colorodo and Arizona Relationship between enamel mottling & excessive intake of fluoride in 1931 by Smith etal, Churchill JV, and Velu R etal H. Trendley Dean and Arnold Mottling : Concentration of fluoride in drinking water Moderate to severely pitting and staining: pre-eruptively induced enamel porosity 29. 2 to 10 ppm- direct inhibitory effect on enzymatic function of Ameloblasts: resulting in defective matrix formation and subsequent hypominerlization Hypocalcified enamel easily becomes hypoplastic after eruption due to abrasion and wear No fluorosis- additional intake of F once crown formed and topical applications 30. CRITERIA FOR DIAGNOSIS OF ENAMEL FLUOROSIS Dean score Criteria 0 0.5 1.0 2.0 3.0 4.0 -Normal enamel -Questionable mottling: normal translucency is varied by a few white flecks or white spots. -very mild mottling: white opaque areas are scattered over the teeth;