Fluoride is a chemical that is added to public water supply by many local governments in order to prevent tooth decay. Water fluoridation is the practice of adding supplemental fluoride in the form of sodium fluoride (NaF) to the water supply in order to help prevent dental caries (cavities) and reverse tooth decay in the general population. The Centers for Disease Control and Prevention (CDC) named water fluoridation "one of ten great public health achievements of the 20th Century."
Fluoride is a slightly altered, or ionic, form of the chemical element fluorine, and is considered both an element and a nutrient. In 1951, two researchers from Indiana University published an article in the Journal of Nutrition, which reported that fluoride prevented tooth decay in rats fed corn and sugar. Following this paper, the University sold its fluoridation technology to Procter & Gamble, and the chemical was added to Crest® toothpaste.
Fluoride compounds, such as calcium fluoride, are naturally occurring in drinking water and foods, usually in very small amounts. Today, fluoride is generally consumed in the supplemental form because it is added to drinking water by many municipal governments. Several brands of bottled water also contain added fluoride. While companies are not required to state the fluoride level on the label, the fluoride levels are monitored. The U.S. Food and Drug Administration (FDA) places limits on how much fluoride is allowed in each bottle. Bottles with no fluoride added may contain up to 2.4 milligrams per liter. For those with fluoride added, the limit is 1.7 milligrams per liter.
The American Dental Association and the World Health Organization recommend raising the amount of fluoride in water supplies to an amount slightly above levels currently established by most worldwide municipal governments. Currently, municipal governments add fluoride to water at a rate of 0.7-1.2 parts per million. The U.S. Environmental Protection Agency has stated the maximum amount of fluoride to be added to drinking water is 4 parts per million.
Most major health advocacy organizations and government agencies support adding moderate amounts of fluoride to water in order to lower community rates of dental complications. Although there is strong scientific evidence suggesting that water fluoridation is safe, some individuals and advocacy organizations oppose water fluoridation, citing anecdotal evidence that the ingestion of the chemical may damage the brain and increase the risk for bone cancer in adolescent boys, though quality studies substantiating these concerns are lacking.
The controversy surrounding the potential adverse effects of fluoride is focused upon its addition or reduction in municipal water supplies. Some opponents have argued that long-term health risks of fluoride are unknown and the cost is high compared to the benefit it provides. Others note that the dose may not be precisely controlled when added to the water and that those receiving the water cannot choose to go without fluoride treatment. Those in favor of water fluoridation contend that the level of fluoride allowed in water is not enough to cause any serious adverse effects. They also maintain that the amount of money saved by preventing dental caries makes up for the cost of adding fluoride to water. Australia's National Health and Medical Research Council (NHMRC) conducted a systematic review investigating the safety of water fluoridation and found that when water is fluoridated to optimal levels, it does not appear to increase the risk for bone fractures, cancer, or other adverse health effects.
Fluoridated salt and fluoridated milk are currently being investigated and may be an alternative to fluoridated water. Several countries, such as Jamaica and Colombia, use fluoridated salt and have seen a decline in dental caries since its introduction.

Related Terms

Dental fluorosis, fluoride deficiency, fluoride poisoning, fluoride therapy, fluorosis, stannous fluoride, tooth decay.