What are the proven effects of fluoride?

Strengthen enamel. Every meal, most drinks, and snacks create damage via acids or bacterial acids produced by the sugar intake. This causes demineralizatoin and loss of hydroxide from hydroxyapetite weakening the tooth. Fluoride replaces the lost mineral and forms a stronger fluorapetite. Remineralizes. However too much Fluoride during tooth developement can actually cause damage to the teeth.
Hardens tooth enamel. Enamel has a crystalline structure. Fluoride gets incorporated in and on the enamel to make it harder and less likely to soften when exposed to acid producing bacteria.

Related Questions

What are the proven side effects of using fluoride (at normal doses)?

None. There are no proven side effects of using Fluoride at normal doses. Fluoride is an all natural mineral which occurs in the earth and ground water all over the world. It was discovered by accident that it makes teeth stronger due to a naturally high concentration of Fluoride in ground water in colorado around 1900. Humans have evolved drinking Fluoride since the beginning of time. Read more...