Water fluoridation is the controlled adjustment of fluoride to a public water supply solely to reduce tooth decay. Fluoridated water contains fluoride at a level that is effective for preventing cavities; this can occur naturally or by adding fluoride.
Fluoridated water operates on tooth surfaces: in the mouth, it creates low levels of fluoride in saliva, which reduces the rate at which tooth enamel demineralizes and increases the rate at which it remineralizes in the early stages of cavities.[3] Typically a fluoridated compound is added to drinking water, a process that in the U.S. costs an average of about $1.17 per person-year. Defluoridation is needed when the naturally occurring fluoride level exceeds recommended limits.
In 2011, the World Health Organization suggested a level of fluoride from 0.5 to 1.5 mg/L (milligrams per litre), depending on climate, local environment, and other sources of fluoride. Bottled water typically has unknown fluoride levels.
The water fluoridation controversy arises from political, moral, ethical, economic, and safety concerns regarding the water fluoridation of public water supplies. For deprived groups in both maturing and matured countries, international and national agencies and dental associations across the world support the safety and effectiveness of water fluoridation.[3] Authorities' views on the most effective fluoride therapy for community prevention of tooth decay are mixed; some state water fluoridation is most effective, while others see no special advantage and prefer topical application strategies.
Those opposed argue that water fluoridation has no or little cariostatic benefits, may cause serious health problems, is not effective enough to justify the costs, is pharmacologically obsolete, and presents a moral conflict between the common good and individual rights.