1. F LUORIDES By Dr. Shahzadi Tayyaba Hashmi DNT 353

2. LEARNING OBJECTIVES Historical background of fluorides in relation to dentistry Natural occurrence of fluorides Mechanism of action of fluoride Methods of introducing fluoride to prevent dental caries

3. H ISTORICAL BACKGROUND OF FLUORIDES The man who had the greatest impact on the early history of water fluoridation was Dr. Frederick McKay who arrived in Colorado in 1901 He noticed that many of his patients, particularly those who had lived in the area all their lives, had an apparently permanent stain on their teeth which was known to their local inhabitants as ‘Colorado stain’

4. H ISTORICAL BACKGROUND OF FLUORIDES He called the stain ‘mottled enamel ’ and said that it was characterized by, minute white flecks, or yellow or brown spots, scattered irregularly over the surface of tooth and entire tooth surface is of a dead paper white colour McKay and his fellow doctor, Dr.Isaac Binton examined the children in public schools of Colorado Springs In all schools, they discovered that 87.5 percent of the children who were living in this area had mottled teeth When the sample of water from that area had been examined, the results showed that in all these areas the fluoride levels were very high So fluorine was the element that was the real cause of enamel mottling

5. N ATURAL OCCURRENCE OF FLUORIDES Fluorides in minerals and earth’s crust (Fluoroapatite, Cryolite) Fluorides in water Fluorides in food Sea food ( salmon and other fish contain 20 ppm of fluoride) Rock salt (40-200 ppm fluoride) Tea (100-400 ppm fluorides) Leafy plants Fluoride drinks ( fresh and fruit juices contain little amount of fluoride) Fluorides in pharmaceutical products ( e.g sodium fluoride tablets and fluoride gels)

7. M ECHANISM OF ACTION OF FLUORIDES 1. Topical 2. Systemic 3. antibacterial

10. M ECHANISM OF ACTION OF FLUORIDES 1) TOPICAL: Inhibits Demineralization Promotes Remineralization FLUORIDES ROLE IN REMINERALIZATION: When bacteria metabolize carbohydrate and produce acid, fluoride is released from dental plaque in response to lower pH levels at the tooth interface To be more acid resistant and contain more fluoride, the demineralized enamel crystal structure takes up released plaque fluoride and salivary fluoride along with calcium phosphate The pH in the oral cavity falls within seconds of ingestion of dietary sugars Low pH leads to demineralization of the tooth structure

11. FLUORIDES ROLE IN REMINERALIZATION When pH returns to normal/neutral, remineralization can occur The original mineral apatite structure of teeth is rich in carbonate, has relatively little fluoride and is relatively soluble Enamel which mineralizes under the influence of fluoride has a low carbonate content, thus giving a reduced solubility ( formation of Fluoroapatite)

12. M ECHANISM OF ACTION OF FLUORIDES 2) Systemic improves enamel crystallinity ( strengthens teeth by the formation of harder enamel by converting Hydroxyapatite crystals to Fluoroapatite a) Fluoroapatite is less vulnerable to damage from plaque acids b) reduces acid solubility c) improves tooth morphology d) Several studies have reported that teeth formed in fluoridated communities or exposed to fluoride supplements pre-eruptively tend to be smaller and have shallower pits and fissures than teeth formed in non-fluoridated communities or not exposed to pre- eruptive fluoride supplements

13. M ECHANISM OF ACTION OF FLUORIDES 3) ANTIBACTERIAL: Fluoride concentrates in plaque disrupts enzyme systems Fluoride inhibits bacterial metabolization of carbohydrates to produce acid and affects the bacterial production of adhesive polysaccharides When fluoride is constantly present, streptococcus mutans produce less acid