Fluoride

Fluoride is a compound of fluorine with another element or radical. Fluoride compounds are present in drinking water and some foods. Fluoride ions replace hydroxyl ions in hydroxyapatite in teeth, forming fluorapatite, which leads to fewer cavities. Fluoride compounds are therefore added to some toothpastes and dentists may also give a yearly fluoride treatment.

Fluoride, in combination with calcium and vitamin D, also increases bone mass and lowers the risk of backbone fractures associated with osteoporosis.