Fluorine is essential for the normal mineralization of bones and the formation of dental enamel. Thus 96% of the fluoride in the body is found in bones and teeth. Fluorine and calcium have strong affinity and function together, mainly in the outer parts of bones.
Traces of fluorine in teeth help to protect them against decay. Fluorine prevents dental caries, by reducing the solubility of the enamel in acids produced by bacteria. A very small amount of the mineral may help in development of tooth, but excess causes dental fluorosis a condition seen in endemic areas. Defluoridation helps in removing fluorides from water.