Fluoride is a chemical that helps prevent tooth decay. It is added to local water supplies, toothpastes, and other mouth care products.

Fluoride controls bacteria and makes teeth stronger and more resistant to decay. Fluoride also helps repair teeth that have already been slightly damaged by plaque.

Fluoride supplements are available by prescription if concentrations in the local water supply are too low. Usually, fluoride levels are only low in well water and some water supplies in rural areas.