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Related terms
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Related Terms
  • Dental fluorosis, fluoride deficiency, fluoride poisoning, fluoride therapy, fluorosis, stannous fluoride, tooth decay.

  • 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.

Theory / Evidence
  • Hydroxide ions in calcium hydroxyapatite of the teeth, which protect against cavities, are replaced by fluoride ions from water or toothpaste. The resulting chemical is calcium fluoroapatite. This chemical has a lower pH and is considered to be more stable and consequently, fewer cavities are thought to result. From a public health perspective, water fluoridation is encouraged because it is thought to decrease the likelihood of the development of cavities, especially in children who do not receive routine dental care.
  • Anecdotal evidence has associated the consumption of fluoridated water with impaired thyroid function, weakened bones, neurotoxicity and bone cancer in boys. Opponents of water fluoridation claim that the possible risks posed to communities consuming fluoride outweigh the potential benefits.
  • Published evidence of toxicity due to fluoride pertains to industrial accidents and mechanical error. For instance, in 2002, seven children experienced nausea and vomiting after an electrical circuit that energized a school fluoride system deposited too much of the chemical in the water system due to error.
  • A 2009 meta-analysis by Walsh et al. evaluated the efficacy of fluoride containing toothpastes at different concentrations in children and adolescents by reviewing 75 trials. This review found that fluoride-containing toothpaste may better prevent dental caries when compared to placebo, but more significantly at fluoride concentrations of 1000 parts per million or greater.
  • A 2010 meta-analysis by Yengopal, et al. evaluated the use of fluoridated salt in children aged 6-15 years. They concluded that fluoridated salt was effective in preventing dental caries (cavities). They also compared its effects to fluoridated water and found it to be equally as effective.
  • A 2007 meta-analysis of 20 studies by Griffin et al. in the Journal of Dental Research evaluated the effectiveness of fluoride in preventing dental caries in adults. Fluoride was given to treatment subjects through municipal water fluoridation, self-administration, and professional administration. The authors concluded that results of this meta-analysis suggested that fluoride prevents dental caries among adults of all age groups.
  • A 2003 systematic review of 34 trials by Marinho et al. evaluated the efficacy of fluoride mouth rinses for preventing dental caries in children and adolescents. All children and adolescents who used the fluoride mouthwashes experienced a decrease in decayed, missing, or filled tooth surfaces. The authors found a lack of information about adverse effects or the acceptability of the mouthwash treatment regimens.
  • A 2000 systematic review published by McDonagh et al. reviewed 214 human studies to examine the safety and efficacy of fluoridation of drinking water. The authors concluded that water fluoridation could be associated with a reduction in the number of children's teeth affected by dental caries, as well as an increased proportion of children without any caries.


Author information
  • This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (

  1. American Dental Association.
  2. Centers for Disease Control and Prevention (CDC).
  3. Griffin SO, Regnier E, Griffin PM, et al. Effectiveness of fluoride in preventing caries in adults. J Dent Res 2007 May;86(5):410-5.
  4. Jha SK, Singh RK, Damodaran T et al. Fluoride in groundwater: toxicological exposure and remedies. J Toxicol Environ Health B Crit Rev. 2013;16(1):52-66.
  5. Marinho VC, Higgins JP, Logan S, et al. Fluoride mouthrinses for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2003;(3):CD002284.
  6. McDonagh MS, Whiting PF, Wilson PM, et al. Systematic review of water fluoridation. BMJ. 2000 Oct 7;321(7265):855-9.
  7. Muhler JC, Day HG. Effect of stannous fluoride in food and in drinking water on caries prevention in rats on high sucrose and coarse corn diets. J Nutr. 1951 Jul;44(3):413-21.
  8. Natural Standard: The Authority on Integrative Medicine.
  9. Sidhu KS, Kimmer RO. Fluoride overfeed at a well site near an elementary school in Michigan. J Environ Health. 2002 Oct;65(3):16-21, 38.
  10. U.S. Environmental Protection Agency (EPA).
  11. Walsh T, Worthington HV, Glenny AM et al. Fluoride toothpastes of different concentrations for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2010 Jan 20;(1):CD007868.
  12. World Health Organization.
  13. Yengopal V, Chikte UM, Mickenautsch S, Oliveira LB, Bhayat A. Salt fluoridation: a meta-analysis of its efficacy for caries prevention. SADJ. 2010 Mar;65(2):60-4, 66-7.

  • Fluoride is naturally found in very low amounts in the ocean water, some foods, and most sources of drinking water. Fluoride may also be found in groundwater, due to the wear of rocks and sediments containing fluoride-bearing minerals. The natural concentration of fluoride in most water sources is significantly below what is considered an effective amount to prevent cavities, which is estimated to be 0.05 milligrams per kilogram of body weight daily. Therefore, most local governments add fluoride to water supplies above such natural concentrations to prevent the development of cavities, especially in children.
  • Most soft drinks and juices contain detectable levels of fluoride. However, the exact concentration per beverage may not be indicated on the label and may not be standardized.
  • Some individuals at a high risk for dental cavities may receive a prescription form of fluoride. U.S. Food and Drug Administration (FDA) approval of fluoride supplements is currently lacking.

Copyright © 2011 Natural Standard (

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.

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