F-; Fluoride is an anionic form of fluorine. According to EFSA it “has no known essential function in human growth and development and no signs of fluoride deficiency have been identified.” Although not being essential for tooth development, fluoride is known for its anti-caries effect: “(…) exposure to fluoride leads to incorporation into the hydroxyapatite of the developing tooth enamel and dentin. The resulting fluorohydroxyapatite is more resistant to acids than hydroxyapatite. Thus, teeth which contain fluoroapatite are less likely to develop caries.”; “In bone, the partial substitution of fluoride for hydroxyl groups of apatite alters the mineral structure of the bone. In excessive doses, fluoride can delay mineralisation.” (EFSA NDA. 2013).