Water fluoridation is the controlled addition of fluoride to a public water supply to reduce tooth decay. Fluoridated water has 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. Typically a fluoridated compound is added to drinking water, a process that in the U.S. costs an average of about $0.95 per person-year. Defluoridation is needed when the naturally occurring fluoride level exceeds recommended limits. A 1994 World Health Organization expert committee suggested a level of fluoride from 0.5 to 1.0 mg/L (milligrams per litre), depending on climate. Bottled water typically has unknown fluoride levels, and some domestic water filters remove some or all fluoride.
Water fluoridation: The addition of fluoride to water supplies that are low in fluoride in order to prevent dental caries without curing light. For years now, water fluoridation has reduced pain and suffering related to tooth decay, reduced tooth loss, reduced time lost from school and work and money spent on dental care. A significant advantage of water fluoridation is that anyone, regardless of socioeconomic level, can enjoy its benefits.
The effectiveness of water fluoridation has been fully documented in the scientific literature. Numerous studies have proven fluoride's effectiveness in decay prevention in the primary teeth of infants and children, as well as in the permanent teeth of children, adolescents and adults, including senior citizens. As with other nutrients, fluoride is safe and effective when used and consumed properly. Fluoridating community water supplies, dental supplies at optimal levels, is an effective and safe method for preventing tooth decay.
The goal of water fluoridation is to prevent a chronic disease whose burdens particularly fall on children and on the poor. Its use presents a conflict between the common good and individual rights. It is controversial, and opposition to it has been based on ethical, legal, safety, and efficacy grounds. Health and dental organizations worldwide have endorsed its safety and effectiveness. Its use began in 1945, following studies of children in a region where higher levels of fluoride occur naturally in the water. Researchers discovered that moderate fluoridation prevents tooth decay, and as of 2004 about 400 million people worldwide received fluoridated water.