Water fluoridation
Water fluoridation is the controlled addition of fluoride to a public water supply for the purpose of reducing tooth decay.[1] Drinking fluoridated water creates low levels of fluoride in saliva, and this reduces the rate at which tooth enamel demineralizes and increases the rate at which it remineralizes in the early stages of cavities.[2] It is currently believed that the optimal level of fluoridation is 0.6 to 1.1 mg/L (milligram per liter), depending on climate.[3] Typically a fluoridated compound is added to drinking water, a process that costs about $0.72 per person per year (range $0.17–$7.62, in 1999 U.S. dollars).[1] Defluoridation is needed when the naturally occurring fluoride level exceeds recommended limits,[4] because fluoride is a cumulative toxin[5]. Bottled water typically has unknown fluoride levels, and some more-expensive household filters remove some or all fluoride.[6] Other methods of fluoride therapy include fluoridation of salt, milk, and toothpaste[7].
