Water fluoridation is the practice of adding fluoride compounds to water with the intended purpose of reducing tooth decay in the general population. Many North American and Australian municipalities fluoridate their water supplies, believing that this practice will reduce tooth decay at a low cost. Currently 66% of United States residents on public water supplies have fluoridated water.

Water purveyors typically add a fluoride, in the form of sodium hexafluosilicate or hexafluosilicic acid, at a level between 0.7 and 1.2 ppm. Fluorides such as sodium fluoride (NaF), sodium monofluorophosphate (SMFP), tin(II) fluoride (SnF2), and amine fluorides are also common ingredients in toothpaste.

Water fluoridation has provoked controversy, though opponents of fluoridation are a minority in the scientific community. Whether for health concerns, concerns of consent, or because their people are receiving fluoride through other means, some governments have ceased or decided not to start fluoridating their water.

While the use of fluorides for prevention of dental caries was discussed already in the 19th century in Europe, community water fluoridation owes its origin in part to the research of Dr. Frederick McKay, who pressed the dental community for an investigation into what was then known as "Colorado stain." In 1909, of the 2,945 children seen by Dr. McKay, 87.5% had some degree of stain or mottling. All the affected children were from the Pikes Peak region. Despite having a negative impact on the physical appearance of their teeth, the children with stained or mottled teeth also had fewer cavities than other children. McKay brought the problem to the attention of Dr. G.V. Black, who later became known as the father of modern dentistry, and Black's interest into the Colorado stain led to greater interest throughout the dental profession.

Initial hypotheses for the staining included poor nutrition, overconsumption of pork or milk, radium exposure, childhood diseases, or a calcium deficiency in the local drinking water. In 1931, researchers finally concluded that the cause of the Colorado stain was a high concentration of fluoride ions (above 1 ppm) in the region's drinking water. Pikes Peak's rock formations contained the mineral cryolite, one of whose constituents is fluoride. As the rain and snow fell, the resulting runoff water picked up the fluoride as it migrated to the water supply.

Dental research then moved toward determining a safe level for fluoride in water supplies. The research had two goals: (1) to warn communities with a high concentration of fluoride of the danger, initiating a reduction of the fluoride levels in order to prevent the Colorado stain, currently known as dental fluorosis, and (2) to encourage communities with a low concentration of fluoride in drinking water to increase the fluoride levels in order to help prevent tooth decay.

The classic epidemiological study to attempt to determine the optimal level of fluoride in water was led by Dr. H. Trendley Dean, a dental officer of the U.S. Public Health Service, in 1934. His research on the fluoride - dental caries relationship, published in 1942, included 7,000 children from 21 cities in Colorado, Illinois, Indiana, and Ohio. The study concluded that the optimal level of fluoride which minimized the risk of severe fluorosis but had positive benefits for tooth decay was 1 part per million (ppm). In 1939, Dr. Gerald J. Cox conducted laboratory tests on fluoride and suggested to add fluoride to drinking water (or other media such as milk or bottled water) in order to improve oral health. In 1937 already, dentists Henry Klein and Carroll E. Palmer had considered the possibility of fluoridation to prevent cavities, after their evaluation of data gathered by a Public Health Service team at dental examinations of American Indian children. In a series of papers published afterwards (1937-1941), yet disregarded by his colleagues within the U.S.P.H.S., Klein summarized his findings on tooth development in children and related problems in epidemiological investigations on caries prevalence.

In the mid 1940s, four widely-cited studies were conducted. The researchers investigated cities that had both fluoridated and unfluoridated water. The first pair was Muskegon, Michigan and Grand Rapids, Michigan, making Grand Rapids the first community in the world to modify its fluoride levels in drinking water to benefit dental health on January 25, 1945. Kingston, New York was paired with Newburgh, New York. Oak Park, Illinois was paired with Evanston, Illinois. Sarnia, Ontario was paired with Brantford, Ontario, Canada. The research found a decrease in the incidence of tooth decay in cities which had added fluoride to water supplies.

Water fluoridation has also received some attention in popular culture. Stanley Kubrick's 1964 film Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb satirized an urban legend declaring water fluoridation to be a communist conspiracy.

Currently, there is some concern among dental professionals that the growing use of bottled water may decrease the amount of fluoride exposure people will receive. Some bottlers such as Dannon have begun adding fluoride to their water. Most bottlers, however, do not add fluoride, and fluoride concentrations are not usually labelled on the bottle. As a result, people who have fluoridated water supplies may receive less than amounts of fluoride that fluoride proponents recommend if they choose bottled water over tap water.

As of May 2000, 42 of the 50 largest U.S. cities have water fluoridation. 67% of Americans are living in communities with fluoridated water according to a 2002 study. As of 2001, 19 states have at least 75% of their population receiving fluoridated water. There is a CDC database for researching the water fluoridation status of neighborhood water.

Water fluoridation is generally supported by the public. In 1998, 70% of people polled believed community water should be fluoridated, with 18% disagreeing and the rest undecided.

The issue of whether or not to fluoridate waters supplies occasionally arises in local governments. For example, on November 8, 2005, citizens of Mt. Pleasant, Michigan voted 63% to 37% in favor of reinstating fluoridation in public drinking water after a 2004 ballot initiative ceased water fluoridation in the city.[21] At the same time, voters in Xenia, Ohio; Springfield, Ohio; Bellingham, Washington; and Tooele City, Utah all rejected water fluoridation.

The cost of fluoridating water supplies in the United States has been researched. In cities with a population of over 50,000 people, fluoridation costs 31 cents per person per year. The cost rises to $2.12 per person in cities with a population below 10,000.

Approximately 40% of the Canadian population receives fluoridated water.

Implementation of fluoridation usually lies with provincial or city governments. Brantford, Ontario became the first city in Canada to fluoridate its water supplies in 1945. In 1955, Toronto approved water fluoridation, but delayed implementation of the program until 1963 due to a campaign against fluoridation by broadcaster Gordon Sinclair. The city continues to fluoridate its water today. Historically, British Columbia has been the province with least percentage of its population receiving fluoridated water. Montreal may be the last major city in Canada which does not fluoridate its water supplies.

Most of Europe does not fluoridate their water supply.

The Republic of Ireland is the only EU nation to have mandatory fluoridation. In the United Kingdom 10% of the population receives optimally fluoridated water - including two major cities: Birmingham and Newcastle upon Tyne.

After a consultation on children's oral health, Scotland retained permissive legislation allowing health authorites to request fluoridation of the water supply.

France does not fluoridate their water supply. As "fluoride chemicals are not included in the list of 'chemicals for drinking water treatment'. This is due to ethical as well as medical considerations.", Directeur de la Protection de l'Environment, August 25, 2000). However, the use of fluoridated salt is widespread.

Germany has rejected water fluoridation. As the German Federal Minster of Health "generally, in Germany fluoridation of drinking water is forbidden. The relevant German law allows exceptions to the fluoridation ban on application (as was the case in the Kassel-Wahlershausen experiment in the 1950´s). The argumentation, in 1999, of the Federal Ministry of Health against a general permission of fluoridation of drinking water is the problematic nature of compulsory medication." (Gerda Hankel-Khan, Embassy of Federal Republic of Germany, September 16, 1999). However, experience shows that opinions change with the official in charge. In common with France and Switzerland, the use of fluoridated salt is widespread in Germany.

In Switzerland since 1962 two fluoridation programmes had operated in tandem: water fluoridation in the City of Basle, and salt fluoridation in the rest of Switzerland (around 83% of domestic salt sold had fluoride added). However it became increasingly difficult to keep the two programmes separate. As a result some of the population of Basle were assumed to use both fluoridated salt and fluoridated water. In order to correct that situation, in April 2003 the State Parliament agreed to cease water fluoridation and officially expand salt fluoridation to Basle.

The government of South Africa supports the fluoridation of water supplies.

In Brazil, about 45% of the cities have a fluoridated water supply. Government studies reported a decrease in cavities on the affected population between 40% and 80%.

In Chile 70.5% of the population receive optimally fluoridated water (10.1 million adjusted, 604,000 naturally ocurring).

Australia has fluoridation in all but one state, Queensland, in which water fluoridation is under local government control. The City of Geelong, west of Melbourne, does not fluoridate its water supplies. This is depsite the fact that all of Melbournes water is flouridated Many regional centres in Queensland do fluoridate their water supply, however Brisbane, the state capital, currently does not add fluoride to its drinking water. The first town to fluoridate the water supply in Australia was Beaconsfield, Tasmania in 1953.

Water fluoridation equipment has, on occasion, malfunctioned in the United States. Perhaps the worst incident in the United States occurred in Hooper Bay, Alaska in 1992. When fluoridation equipment failed, a large amount of fluoride was released into the drinking water supply and "296 people were poisoned; 1 person died," marking the "first reported death due to fluoride toxicity caused by drinking water from a community water system."

Water fluoridation by public authorities has occasionally provoked controversy, though opposition to fluoridation is a minority viewpoint. Advocates of water fluoridation say that fluoridation is similar to fortifying salt with iodine, milk with vitamin D and orange juice with vitamin C and say it is an effective way to prevent tooth decay and improve oral health over a lifetime, for both children and adults. Those opposed to public fluoridation of drinking water say that water fluoridation can have negative health effects such as dental fluorosis which outweighs the purported benefits of water fluoridation. Some opponents claim that releasing fluoride compounds into municipal water takes away individual choice as to the substances a person ingests and amounts to mass medication. Some suggest water fluoridation is part of a scheme to dispose of a toxic industrial byproduct or administer mind control drugs to the population.Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts.
Virtual Magic is a human knowledge database blog. Text Based On Information From Wikipedia, Under The GNU Free Documentation License. Copyright (c) 2007 Virtual Magic. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".

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