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Fluoridation Today

Up until the 1980s the majority of research into the benefits of fluoridation reported substantial reductions (50-60% on average) in the incidence of tooth decay where water supplies had fluoride levels of about one ppm. By the end of the decade however, the extent of this reduction was being viewed more critically. By the 1990s, even some fluoridation proponents suggested that observed tooth decay reduction, directly as a result of water fluoridation, may only have been at levels of around 25%. Other factors, such as education and better dental hygiene, could also be contributing to the overall reduction in tooth decay levels. Fluoride in food, salt, toothpastes, rinses, and tablets, have undoubtedly contributed to the drastic declines in tooth decay during the twentieth century. It also remains unclear as to what, if any, are the side effects of one ppm levels of fluoride in water ingested over many years.

Although it has been argued that any risks associated with fluoridation are small, these risks may not necessarily be acceptable to everyone. The fact that only about 50% of U.S. communities have elected to adopt fluoridation is indicative of people's cautious approach to the issue. In 1993, the National Research Council published a report on the health effects of ingested fluoride and attempted to determine if the maximum recommended level of four ppm for fluoride in drinking water should be modified. The report concluded that this level was appropriate but that further research may indicate a need for revision. The report also found inconsistencies in the scientific studies of fluoride toxicity and recommended further research in this area.



Martin, B. Scientific Knowledge in Controversy: The Social Dynamic of the Fluoridation Debate. Albany, New York: State University of New York Press, 1991.

Whitford, G.M. The Metabolism and Toxicity of Fluoride. Basel, New York: Karger, 1989.


Hileman, B. "Fluoridation of Water." Chemistry and Engineering News 66 (August 1, 1988): pp. 26-42.


National Research Council Committee on Toxicology. Health Effects of Ingested Fluoride. Washington, DC: National Academy Press, 1993.

United States Department of Health and Human Services Committee to Coordinate Environmental Health and Related Programs. Ad Hoc Subcommittee on Fluoride. Review of Fluoride Benefits and Risks: Report of the Ad Hoc Sub-committee on Fluoride. Washington, DC: Public Health Service, Department of Health and Human Services, 1991.

Nicholas C. Thomas


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—A pure substance that can not be changed chemically into a simpler substance.


—The addition to a city's water supply of chemicals that release fluoride into the water.


—The ionic form (negatively charged) of the element fluorine which is soluble in water.

Parts per million (ppm)

—A way to express low concentrations of a substance in water. For example, 1 ppm of fluoride means 1 gram of fluoride is dissolved in 1 million grams of water.

Additional topics

Science EncyclopediaScience & Philosophy: Ferroelectric materials to Form and matterFluoridation - Fluoride And Tooth Decay, Early Fluoridation Studies, To Fluoridate Or Not To Fluoridate, Fluoridation Outside The United States