The scientific consensus that fluoridation is a safe and effective public health measure is based on reviews of the relevant research by relevant science and health experts of over seven decades of studies.

The 34 reviews and studies listed below, published since 2000, have unanimously agreed with the scientific consensus that community water fluoridation reduces dental decay.  None of these reviews reported any health risks from drinking optimally fluoridated water, only an slight increased risk of very mild to mild dental fluorosis. 

The 34 reviews/studies include:

  1. the 2018 National Toxicity Program fluoride study, An Evaluation of Neurotoxicity Following Fluoride Exposure from Gestational Through Adult Ages in Long-Evans Hooded Rats: At these exposure levels, we observed no exposure-related differences in motor, sensory, or learning and memory performance on running wheel, open-field activity, light/dark place preference, elevated plus maze, pre-pulse startle inhibition, passive avoidance, hot-plate latency, Morris water maze acquisition, probe test, reversal learning, and Y-maze. T3, T4, and TSH levels were not altered as a function of 10 or 20 ppm F- in the drinking water. No exposure-related pathology was observed in the heart, liver, kidney, testes, seminal vesicles, or epididymides. Mild inflammation in the prostate gland was observed at 20 ppm F-. No evidence of neuronal death or glial activation was observed in the hippocampus at 20 ppm F-. (McPherson, et al., Neurotox Res. 2018)
  2. the 2018 study, Water Fluoridation and Dental Caries in U.S. Children and Adolescents: These findings confirm a substantial caries-preventive benefit of CWF for U.S. children and that the benefit is most pronounced in primary teeth. (Slade, et al., J Dent Res. 2018)
  3. the 2018 Water Fluoridation Health Monitoring Report for England:
    Dental health:
    • Five-year-olds in areas with water fluoridation schemes were much less likely to experience tooth decay, and less likely to experience more severe decay than in areas without schemes
    • The chances of having a tooth/teeth removed in hospital because of decay were also much lower in areas with water fluoridation schemes
    • Children from both affluent and deprived areas benefitted from fluoridation, but children from relatively deprived areas benefitted the most.
    • Dental fluorosis, at a level that may effect the appearance of teeth, was observed in 10% of children/young people examined in fluoridated cities. However, there was no difference between children and young people surveyed in fluoridated and nonfluoridated cities when asked about their opinion on the appearance of their teeth, taking into account concerns which have resulted from any cause (eg poor alignment, decay, trauma or fluorosis).
    Non-dental health outcomes:  Taken alongside the existing wider research, our results do not provide convincing evidence of higher rates of hip fracture, Down’s syndrome, kidney stones, bladder cancer, or osteosarcoma (a cancer of the bone) due to fluoridation schemes.
    Conclusion: The findings of this report agree with the view that water fluoridation is an effective and safe public health measure to reduce the frequency and severity of dental decay, and narrow differences in dental health between more and less deprived children and young people.
  4. the 2018 study, Contemporary evidence on the effectiveness of water fluoridation in the prevention of childhood caries – Australia: Analysis of contemporary data representative of the Australian child population found consistent associations between %LEFW and childhood caries, which persisted when socioeconomic differences were adjusted across exposure groups, supporting the continued effectiveness of water fluoridation. (Spencer, et al., Community Dent Oral Epidemiol. 2018)
  5. the 2018 Food Safety Authority of Ireland Fluoride Report: Based on the results of this study, the FSAI Scientific Committee concluded that there is currently no scientific basis for concerns about the safety of children and adults in Ireland from exposure to fluoride from foods and beverages.
  6. the 2018 CDC Statement on the Evidence Supporting the Safety and Effectiveness of Community Water Fluoridation: Water fluoridation is beneficial for reducing and controlling tooth decay and promoting oral health across the lifespan. Evidence shows that water fluoridation prevents tooth decay by providing frequent and consistent contact with low levels of fluoride, ultimately reducing tooth decay by 25% in children and adults.  Additional evidence shows that schoolchildren living in communities where water is fluoridated have, on average, 2.25 fewer decayed teeth compared to similar children not living in fluoridated communities.  The safety and benefits of fluoride are well documented and have been reviewed comprehensively by several scientific and public health organizations. The U.S. Public Health Service; the United Kingdom’s National Institute for Health Research, Centre for Reviews and Dissemination, at the University of York; and the National Health and Medical Research Council, Australia have all conducted scientific reviews by expert panels and concluded that community water fluoridation is a safe and effective way to promote good oral health and prevent decay.  The U.S. Community Preventive Services Task Force, on the basis of systematic reviews of scientific literature, issued a strong recommendation in 2001 and again in 2013, for community water fluoridation for the prevention and control of tooth decay
  7. the 2017 Swedish report, Effects of Fluoride in the Drinking Water: Taking all together, we investigate and confirm the long-established positive relationship between fluoride and dental health. Second, we fnd precisely estimated zero-effects on cognitive ability, non-cognitive ability and math test scores for fluoride levels in Swedish drinking water. Third, we find that fluoride improves later labor market outcomes, which indicates that good dental health is a positive factor on the labor market.
  8. the 2017 National Health and Medical Research Council 2017 Public Statement – Water Fluoridation and Human Health in Australia + Questions & Answers: There is reliable evidence that community water fluoridation helps to prevent tooth decay. The consequences of tooth decay are considerable: dental pain, concern about appearance, costs due to time off school and work, and costs of dental treatment. There is no reliable evidence of an association between community water fluoridation at current Australian levels and any health problems. In Australia, community water fluoridation programs are a safe, effective and ethical way of reducing tooth decay across the population.
  9. the 2017 EPA Response:  Fluoride Chemicals in Drinking Water; TSCA Section 21 Petition:  On November 23, 2016, a TSCA section 21 petition was submitted by the Fluoride Action Network [and 10 other organizations and individuals]. The general object of the petition was to urge EPA “to protect the public and susceptible subpopulations from the neurotoxic risks of fluoride by banning the addition of fluoridation chemicals to water”  On February 17, 2017, "after careful consideration, EPA denied the TSCA section 21 petition, primarily because EPA concluded that the petition has not set forth a scientifically defensible basis to conclude that any persons have suffered neurotoxic harm as a result of exposure to fluoride in the U.S. through the purposeful addition of fluoridation chemicals to drinking water or otherwise from fluoride exposure in the U.S."
  10. the 2017 history of public health use of fluorides in caries prevention: We systematically searched the PubMed database on the preventive role of fluorides in public health, published from 1984 to 2014. ... The role of fluorides in public health prevention has changed in accordance with the knowledge about the fluoride cariostatic mechanism. Previously the most important pre-eruptive effect of fluorides was supplemented by the post eruptive effect. Abundant evidence exists to show the effectiveness of systemic and topical fluorides.
  11. the 2016 World Health Organization report: Fluoride and Oral Health:
    —> Fluoride is effective at controlling caries because it acts in several different ways. When present in dental plaque and saliva, it delays the demineralization and promotes the remineralization of incipient enamel lesions, a healing process before cavities become established. Fluoride also interferes with glycolysis, the process by which cariogenic bacteria metabolize sugars to produce acid. In higher concentrations, it has a bactericidal action on cariogenic and other bacteria. Studies suggest that, when fluoride is ingested during the period of tooth development, it makes teeth more resistant to subsequent caries development. Fluoridated water also has a significant topical effect in addition to its systemic effect (Hardwick et al., 1982). It is well known that salivary and plaque fluoride (F) concentrations are directly related to the F concentration in drinking water. This versatility of action adds to fluoride’s value in caries prevention. Aiding remineralization is likely to be fluoride’s most important action.
    —> Studies from many different countries over the past 60 years are remarkably consistent in demonstrating substantial reductions in caries prevalence as a result of water fluoridation. One hundred and thirteen studies into the effectiveness of artificial water fluoridation in 23 countries conducted before 1990, recorded a modal percent caries reduction of 40 to 50% in primary teeth and 50 to 60% in permanent.
    —> More recently, systematic reviews summarizing these extensive databases have confirmed that water fluoridation substantially reduces the prevalence and incidence of dental caries in primary and permanent teeth. Although percent caries reductions recorded have been slightly lower in 59 post-1990 studies compared with the pre-1990 studies, the reductions are still substantial.
    —> The question of possible adverse general health effects caused by exposure to fluorides taken in optimal concentrations throughout life has been the object of thorough medical investigations which have failed to show any impairment of general health.
  12. the 2016 (update) Best Practice Approach - Community Water Fluoridation -  Association of State and Territorial Dental Directors: Community water fluoridation remains an effective public health strategy for delivering fluoride to prevent tooth decay and is the most feasible and cost-effective strategy for reaching entire communities.
  13. the 2016 systematic review of published studies:  Does cessation of community water fluoridation lead to an increase in tooth decay?  We identified 15 instances of CWF cessation (‘intervention’) in 13 countries, which covered a broad time frame (1956–2003) and diverse geographical and political/economic contexts. Overall, results were mixed, but pointed more to an increase in caries postcessation than otherwise. For example, of the 9 studies with at least moderate methodological quality based on criteria we developed for this review, 5 showed an increase in caries postcessation. 3 studies [in Finland, E. Germany & Cuba] did not show an increase in caries postcessation; however, important postcessation changes (eg, implementation of alternative fluoride delivery programmes) and/or large-scale social change may have contributed to those effects. Importantly, in all three interventions, there were other factors which could have contributed to findings observed. In Finland,18 the CWF-cessation community started to provide fluoride tablets to children postcessation. In East Germany,26 postcessation fissure sealants were paid for by statutory health funds. In Cuba,27 postcessation, all children received fluoride mouth rinses fortnightly, and children aged 2–5 years received 1–2 fluoride varnish applications annually. Those initiatives could have offset an impact of cessation on dental caries.
  14. the 2016 Economic Evaluation of Community Water Fluoridation: Recent evidence continues to indicate that the economic benefit of community water fluoridation exceeds the intervention cost. Further, the benefit–cost ratio increases with the community population size.
  15. the 2015 Manual of Dental Practices, Council of European Dentists: Approximately 6 million people in the UK receive water in which the fluoride content has been adjusted to the optimum level for dental health of around one part of fluoride per million parts of water, or that has a naturally occurring fluoride level of around this level. This means that around one in ten of the total population of the UK is currently receiving water with a fluoride level that is capable of providing protection against tooth decay.
  16. the 2015 U.S. Public Health Service Recommendation for Fluoride Concentration in Drinking Water for the Prevention of Dental Caries:  The article demonstrates how the scientific consensus changes based on legitimate evidence – not fear mongering.
    Systematic reviews of the scientific evidence related to fluoride have concluded that community water fluoridation is effective in decreasing dental caries prevalence and severity.  Effects included significant increases in the proportion of children who were caries-free and significant reductions in the number of teeth or tooth surfaces with caries in both children and adults.  When analyses were limited to studies conducted after the introduction of other sources of fluoride, especially fluoride toothpaste, beneficial effects across the lifespan from community water fluoridation were still apparent.
    Fluoride in saliva and dental plaque works to prevent dental caries primarily through topical -remineralization of tooth surfaces. Consuming fluoridated water and beverages, and foods prepared or processed with fluoridated water, throughout the day maintains a low concentration of fluoride in saliva and plaque that enhances remineralization. Although other fluoride-containing products are available and contribute to the prevention and control of dental caries, community water fluoridation has been identified as the most cost-effective method of delivering fluoride to all members of the community regardless of age, educational attainment, or income level.
  17. the 2015 Cochrane Water Fluoridation Review: Fluoride is a mineral that prevents tooth decay. It occurs naturally in water at varying levels.  Our review found that water fluoridation is effective at reducing levels of tooth decay among children. The introduction of water fluoridation resulted in children having 35% fewer decayed, missing and filled baby teeth and 26% fewer decayed, missing and filled permanent teeth. We also found that fluoridation led to a 15% increase in children with no decay in their baby teeth and a 14% increase in children with no decay in their permanent teeth. These results are based predominantly on old studies and may not be applicable today. 
    The Cochrane review is often cited by fluoridation opponents as supporting their agenda because of its complexity and the fact that restrictive criteria for selecting studies to review resulted in the rejection of the majority of relevant studies.  It is important to understand the review limitations - some of which are discussed in the critique below.
    • the 2016 Critique of the review of 'Water fluoridation for the prevention of dental caries' published by the Cochrane Collaboration: The Cochrane Review maintained that the RCT would be the best design for evaluating  the effectiveness of water fluoridation, while simultaneously acknowledging its impracticability in this  instance.  Although RCTs are the method of choice for evaluating the effectiveness of medicines and  some clinical interventions, literature published during the past 20 years has indicated that they are  inappropriate for evaluating public health preventive programmes and other complex interventions. ... While the overall conclusion that water fluoridation is effective in caries prevention is consistent with previous reviews, many important public health questions could not be answered by the Cochrane Review because of the restrictive inclusion criteria used to judge adequacy of study design and risk of bias. The potential benefits of using wider criteria in order to achieve a fuller understanding of the effectiveness of water fluoridation are discussed.
  18. the 2015  Health Effects of water Fluoridation - An Evidence Review.  Ireland Health Research Board:  In summary the literature found no strong evidence that CWF is definitively associated with negative health effects.
  19. the 2015  review, Fluoridation of water: a literature review of risks or benefits for the population in Ireland exposed to the current levels – including a European policy examination of water fluoridation practices:  To date epidemiological studies suggest water fluoridation is effective in lowering dental caries through inhibiting demineralization and promoting re mineralization making teeth stronger and more resistant to decay.  As a community wide public health measure fluoridation is accessible to all regardless of socio-economic status, educatioal attainment or other social variables. ... At levels of 1 mg/L of fluoride in drinking water, no effects have been established, either positively or negatively on disease or death rates. No differences in nephritis, coronary illness, allergic reactions or cirrhosis and includes: Downs Syndrome, senile dementia, nephrolithiasis, stillbirths and congenital abnormalities.
  20. the 2015 Denver Water Board review of its 62 year fluoride policy: In 2015 anti-F activists attempted to “persuade” the Denver Water Board to discontinue fluoridation.  Fortunately, the Denver Water Board was able to evaluate the evidence from a scientific perspective. The resolution the Denver Water Board Commissioners adopted at its August 26, 2015 meeting stated: Nothing has been presented to the Board or learned in our research [Including the testimony of anti-F activist, Paul Connett, who flew in for a presentation] that would justify ignoring the advice of these public health agencies and medical and community organizations, or deviating from the thoroughly researched and documented recommendation of the U.S. Public Health Service.
  21. the 2014 American Academy of Pediatrics Clinical Report: Fluoride Use in Caries Prevention in the Primary Care Setting: Dental caries is the most common chronic disease of childhood, with 59% of 12- to 19-year-olds having at least 1 documented cavity.  Caries is the “silent epidemic” that disproportionately affects poor, young, and minority populations. ...  Community water fluoridation is a safe, efficient, and cost-effective way to prevent tooth decay and has been shown to reduce tooth decay by 29%.  It prevents tooth decay through the provision of low levels of fluoride exposure to the teeth over time and provides both topical and systemic exposure.
  22. the 2014 Royal Society of New Zealand, Health effects of water fluoridation: There is compelling evidence that fluoridation of water at the established and recommended levels produces broad benefits for the dental health of New Zealanders. In this context it is worth noting that dental health remains a major issue for much of the New Zealand population, and that economically and from the equity perspective fluoridation remains the safest and most appropriate approach for promoting dental public health. The only side effect of fluoridation at levels used in NZ is minimal fluorosis, and this is not of major cosmetic significance. There are no reported cases of disfiguring fluorosis associated with levels used for fluoridating water supplies in New Zealand. ... We conclude that the scientific issues raised by those opposed to fluoridation are not supported by the evidence.
  23. the 2013 European Food Safety Authority review, Scientific Opinion on Dietary Reference Values for fluoride: Fluoride has no known essential function in human growth and development and no signs of fluoride deficiency have been identified. Though fluoride is not essential for tooth development, exposure to fluoride leads to incorporation into the hydroxyapatite of the developing tooth enamel and dentin. The resulting fluorohydroxyapatite is more resistant to acids than hydroxyapatite. Thus, teeth which contain fluoroapatite are less likely to develop caries. Apart from incorporation of fluoride into the dentin and enamel of teeth before eruption, dietary fluoride exerts an anticaries effect on erupted teeth through contact with enamel during consumption, excretion into saliva and uptake into biofilms on teeth. In addition, fluoride interferes with the metabolism of oral microbial cells, by directly inhibiting, for example, glycolytic enzymes and cell membrane-associated H+ ATPases in microbial cells after entry of hydrofluoric acid into their cytoplasm. (Summary, page 2)
  24. the 2013 Community Guide Systematic Review, Dental Caries (Cavities): Community Water Fluoridation: The Community Preventive Services Task Force (CPSTF) recommends community water fluoridation to reduce dental caries (tooth decay). Major Findings:
    • After water fluoridation began, communities saw a median increase of 15 percentage points (based on 11 studies) in the percentage of caries-free children compared to communities without water fluoridation.
    • When community water fluoridation was discontinued, an increase in dental caries occurred.
    • A systematic review of the economic evidence found that the economic benefit of community water fluoridation is greater than the cost
  25. the 2011 SCHER Critical review of any new evidence on the hazard profile, health effects, and human exposure to fluoride and the fluoridating agents of drinking water: Conclusions:
    • Fluoridation chemicals – In the pH-range and at the concentrations of hexafluorosilicates/fluoride relevant for drinking water, hydrolysis of hexafluorosilicates to fluoride was rapid and the release of the fluoride ion was essentially complete. Residual fluorosilicate intermediates were not observed by sensitive F-NMR. These calculated concentrations [of impurities in fluoridation chemicals] are at least two orders of magnitude below drinking water guideline values for these metals established by WHO and other organizations, and therefore are not regarded as an additional health risk. Based on the available chemistry of fluoride in solution, the chemistry of lead and lead ions, and the concentrations of fluoride in tap water, it is highly unlikely that there would be an increased release of lead from pipes due to hexafluorosilicic acid.
    • Genotoxicity and Carcinogenicity – SCHER agrees that epidemiological studies do not indicate a clear link between fluoride in drinking water, and osteosarcoma and cancer in general. There is no evidence from animal studies to support the link, thus fluoride cannot be classified as carcinogenic.
    • Neurotoxicity – SCHER agrees that there is not enough evidence to conclude that fluoride in drinking water at concentrations permitted in the EU may impair the IQ of children. SCHER also agrees that a biological plausibility for the link between fluoridated water and IQ has not been established.
    • Reproductive and developmental effects – SCHER concludes that fluoride at concentrations in drinking water permitted in the EU does not influence the reproductive capacity.
    • Summary – Fluoride, either naturally present or intentionally added to water, food and consumer products, e.g. toothpaste, is generally considered beneficial to prevent dental caries. Considering previous opinions from EFSA and SCCP, SCHER has reviewed the newest information in the area on risk and benefit of using fluoridated drinking water and intake of fluoride from all sources.
  26. the 2011 Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Fluoride: Health Canada's Chief Dental Officer has reviewed the available science on dental effects of fluoride, and sought external expert advice from the scientific dental community. Experts provided a recommendation on the optimal level, which was accepted by Health Canada's Chief Dental Officer. As a result, the optimal concentration of fluoride in drinking water for dental health has been determined to be 0.7 mg/L for communities who wish to fluoridate. This concentration provides optimal dental health benefits and is well below the MAC to protect against adverse effects. The weight of evidence from all currently available studies does not support a link between exposure to fluoride in drinking water at 1.5 mg/L and any adverse health effects, including those related to cancer, immunotoxicity, reproductive/developmental toxicity, genotoxicity and/or neurotoxicity. It also does not support a link between fluoride exposure and intelligence quotient deficit, as there are significant concerns regarding the relevant studies, including quality, credibility, and methodological weaknesses.
  27. the 2008 Systematic review of the efficacy and safety of fluoridation Australian NHMRC: RESULTS: In total, 5418 nonduplicate citations were identified. After applying the inclusion and exclusion criteria, 408 citations were considered potentially eligible for inclusion in the review. After the review of the full papers of potentially eligible articles, 77 citations were included in the review. The summary of findings was presented in the context of the research questions (Table 3).
    RECOMMENDATIONS: Fluoridation of drinking water remains the most effective and socially equitable means of achieving community-wide exposure to the caries prevention effects of fluoride.
  28. the 2007 Dutch Ministry of Health and Welfare and Sports:  Economic evaluation of prevention: further evidence: Fluoridation of drinking water in the Netherlands would probably be cost-saving as the costs of fluoridation will be outweighed by the savings due to reduction of caries. However, people would also run the risk of fluorosis (of aesthetic concern). Although practically feasible, the many objections against fluoridation of drinking water make its implementation rather improbable.
  29. the 2007 Findings and Recommendations of the Fluoride Expert Panel – Health Canada:  Community drinking water fluoridation is still an effective public health method to reduce the prevalence of dental caries in the Canadian population.
  30. the 2006 NRC Scientific Review of EPA’s Standards - Fluoride In Drinking Water: The twelve member committee “was asked to evaluate independently the scientific basis of EPA’s MCLG of 4 mg/L and SMCL of 2 mg/L in drinking water and the adequacy of those guidelines to protect children and others from adverse health effects." The ONLY reasons provided in the report for lowering the MCL from 4 ppm (nearly six times higher than optimally fluoridated water) were extremely specific. The report states, Lowering the MCLG will prevent children from developing severe enamel fluorosis and will reduce the lifetime accumulation of fluoride into bone that the majority of the committee concluded is likely to put individuals at increased risk of bone fracture and possibly skeletal fluorosis, which are particular concerns for subpopulations that are prone to accumulating fluoride in their bone.
    The committee made no recommendation to lower the SMCL below 2.0 ppm (nearly three times the fluoride level of optimally fluoridated water) for any reason. If there were any health concerns from drinking water with a fluoride content of 2.0 ppm, those concerns would have been mentioned. Quotes that allege the committee concluded drinking water fluoridation caused harm are taken from out-of-context discussions of specific studies.
  31. the 2003 Update on Fluorides and Fluorosis (Steven M. Levy, Journal of the Canadian Dental Association):
    Water fluoridation and use of fluoride dentifrice are the most efficient and cost-effective ways to prevent dental caries; other modalities should be targeted toward high-risk individuals.
  32. the 2003 Fluoride Technical Study Group Report, Fort Collins, CO:
  33. the 2000 York, Systematic review of water fluoridation:
  34. the 2000 Community Preventive Services Task Force, Preventing Dental Caries: Community Water Fluoridation: