Precipitate Fluoroappetite. It absorbs calcium & phosphate from saliva and makes insoluble precipitate. This will replace the soluble salts of manganese & carbohydrates- what increase the absorption of F in the body; which in fact was already taken out by the bacterial demineralization. So this in fact makes enamel more acid resistance. Not hard per say. Primary mechanism:- Fluoride ion is easily exchanged for hydroxyl ion (OH ion) coz its smaller than hydroxyl. Plus it has affinity for hydroxyappetite this the fluoroappetite transformation. Voila ! It reduces the rate of enamel solubility Remineralization, of incipient, non-cavitated carious lesion. That’s why if caries hasn’t crossed the CEJ, you can go for F application, coz it can induce remineralization. Antimicrobial activity. The function of F releasing GIC. Basically in low conc, it has the ability to reduce microbial adhesion, slow down the ecological succession, by preventing storage of carbs. Fluoride inhibits bacterial intercellular polysaccharide formation

This is the easiest and most common method used to reduce caries in a community level or as among general population. Fluoride in water in ppm — 1 ppm Optimum water fluoridation in mg — 0.5 – 0.8 mg/litre Below optimum- 0.7mm Below optimum = 0.7 ppm in warmer climates Above optimum = 1.2 ppm in colder climates If there’s no community water fluoridation, then next cost effective method for 6-12yr old, is to go for school water fluoridation instead of F tablets, pastes, gel, mouthwash etc.

Rule of 6 If F in water is more than 0.6ppm , no need If patients is less than 6 months, no need If patient is more than 16yrs, no need