Fluoride is a mineral that occurs naturally in many foods and water. Every day, minerals are added and lost from the enamel layer of a tooth through two processes: demineralization and remineralization. Minerals are lost (demineralization) from the enamel layer of a tooth when acids, formed by plaque bacteria and sugars in the mouth, attack the enamel. Minerals such as fluoride, calcium and phosphate are re-deposited (remineralization) in the enamel layer of the food and water that is consumed. Too much demineralization without sufficient remineralization to repair the enamel layer leads to tooth decay.
Fluoride helps prevent tooth decay by making the tooth more resistant to acid attacks by plaque bacteria and sugars in the mouth. It also reverses early decline. In children younger than 6 years, fluoride is incorporated into the development of permanent teeth, which makes the demineralization of acids difficult. Fluoride also helps accelerate remineralization and also interrupts the production of acid in already erupted teeth of children and adults.