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The Legislative Insider is published during the Legislative Session by the Georgia Dental Association. It contains updates on the activities of GDA's Government Affairs team as well as information about bills relevant to dentists and patient care.

Community Water Fluoridation is Still a Good Idea!

Apr 22, 2025 by Dr. Scott L. Tomar
Community water fluoridation is a safe, effective, and cost-saving public health measure inspired by natural fluoride levels that significantly reduces dental caries and promotes oral health equity.

 

Nature Thought of It First

A reporter recently called me to discuss community water fluoridation and her first question was, “what is fluoride, and why is it in our water?” Apparently, much of the public is unaware that fluoride is a ubiquitous mineral found at some level in rocks, soil, and nearly all bodies of water and that its role in preventing dental caries came from observing natural conditions.

The history of fluoridation started in the early 20th century with the clinical observations of Dr. Frederick McKay, a young dentist from the East Coast who moved west to Colorado Springs to set up his practice. Dr. McKay immediately noticed a prevalent brown staining on his patients’ teeth and started investigating the prevalence and etiology of what was then called “mottled enamel.” Several decades later, high levels of fluoride in the water supply were identified as the agent responsible for the condition subsequently called fluorosis.

Fluoride’s role in caries prevention was first hypothesized by Dr. Henry Klein, the Public Health Service dentist who developed the Decayed, Missing or Filled Teeth (DMFT) index still in use today. In the early 1930s, Dr. Klein led a study of more than 8,200 Native American children living on 76 reservations across six regions of the country and observed that children in the Southwestern region had the lowest caries attack rate (1). That was also an area that had endemic fluorosis, leading him to speculate, “perhaps a measure of the responsibility for the low caries attack rates…may be the result of the drinking of fluoride waters.”

The associations between fluoride concentrations in drinking water, dental caries prevalence, and fluorosis were confirmed in a study conducted by Dr. H. Trendley Dean among 12–14year-olds living in 21 cities in the Midwest and Southwest (2, 3). The findings from that observational study indicated a “sweet spot” of fluoride concentration in drinking water of 1.0 mg/L, at which dental caries severity was substantially lower than in communities with a negligible amount of fluoride in their water, while the prevalence of fluorosis remained relatively low and very mild. That observation led to the hypothesis that communities might be able reproduce nature’s preventive effect by adjusting the fluoride concentration in its water supply to 1.0 mg/L (the recommended fluoride concentration in the United States is now 0.7 mg/L).

The pioneering fluoridation trials in four cities began in 1945, with four nearby cities serving as control communities. After 15 years, the mean DMFT in the fluoridated communities had dropped by 50%–70% relative to the control cities (4). Community water fluoridation grew rapidly during the following decades, and now reaches about 72% of Americans on public water. More than 95% of Georgians on community water systems receive fluoridated water.

Several recent events and reports highlighted in the press have raised questions about the safety and effectiveness of community water fluoridation. However, the science behind the headlines indicates that community water fluoridation is still a safe, effective, and cost-saving measure for reducing the burden of oral disease.


Community Water Fluoridation is Safe

The National Toxicology Program (NTP) issued a monograph on fluoride exposure and neurodevelopment in August 2024 (5). The primary authors of that monograph published a meta-analysis that had been removed from an earlier draft of the NTP Monograph as a stand-alone paper in January 2025 (6), but the monograph and paper shared the same fundamental weakness: of the 72 studies that assessed the association between fluoride exposure and IQ, almost three-fourths of them were ranked as low quality and high risk for bias, and nearly all were from parts of China, India, and Iran with very high levels of fluoride and unknown contaminants in the water. Additional concerns about the study have been noted in an editorial published in the same journal issue (7).

Importantly, the NTP Monograph and meta-analysis found no association between exposure to fluoride at the levels used in community water fluoridation and children’s IQ. A more recent prospective cohort study from Australia also found no association between water fluoridation and children’s IQ (8), nor did other recent systematic reviews on IQ and levels of fluoride exposure relevant to water fluoridation (9, 10). The judge in the recent court case brought against the Environmental Protection Agency relied heavily on the flawed NTP report but acknowledged that there was no evidence of any harm associated with the levels of fluoride used in community water fluoridation. The available evidence indicates that the level of fluoride used in community water fluoridation is not associated with changes in IQ or any other measure of neurodevelopment.


Community Water Fluoridation is Effective

The Cochrane Library issued its latest systematic review on the effectiveness of water fluoridation in October 2023 (11). That review’s stringent inclusion criteria limited it to prospective cohort studies that were started before the initiation of a new fluoridation program, and just one new study was added to its 2015 systematic review on the topic. The authors concluded that contemporary studies of initiation of community water fluoridation show slightly greater reduction in the severity of dental caries and a slightly greater increase in the proportion of caries‐free children, but with smaller effect sizes than pre‐1975 studies. That conclusion has been misinterpreted as meaning that community water fluoridation is no longer effective, but recent studies suggest the proportion of disease incidence prevented by water fluoridation is still in the range of 25%–40% in studies conducted during a time of widespread use of fluoride toothpaste. The absolute number of teeth or tooth surfaces spared from caries may be smaller than it once was, but the prevented fraction remains clinically and financially significant. Many recent cross-sectional studies that did not meet the stringent inclusion criteria for the main analysis were summarized in the report’s Discussion section. The studies were remarkably consistent across countries in showing significantly lower caries severity in fluoridated communities compared with non-fluoridated comparison communities, for both primary and permanent dentitions. As has been shown in U.S. studies, community water fluoridation substantially reduces socioeconomic disparities in caries incidence.


Community Water Fluoridation Saves Money

At contemporary estimates of the prevented fraction of dental caries associated with community water fluoridation, it still saves money. On average, each dollar spent on community water fluoridation saves an average of about $20 in averted treatment (12). Consistent with that finding, recent evidence from Israel and Alaska indicates that discontinuation of community water fluoridation was associated with increased rates of treatment services and costs of care (13, 14).


Bottom Line

Despite recent headlines and fearmongering, the best available evidence indicates that community water fluoridation is a safe, effective, and cost-saving approach to caries prevention. Dentistry should be very proud to champion a public health measure that reduces the need for restorative care, seemingly working against dentists’ economic self-interest. To me, that commitment to disease prevention and health promotion is part of what makes us a true health profession.

 

Dr. Scott L. Tomar is Professor and Associate Dean for Prevention and Public Health Sciences at University of Illinois Chicago College of Dentistry. He is a member of ADA’s National Fluoridation Advisory Committee. CE sessions from Dr. Tomar will be offered at the Annual Convention in June, Fall CE Conference in September and virtually via webinar on May 16.


References

1. Klein H, Palmer CE. Dental caries in American Indian children. Washington, DC: Government Printing Office; 1937.
2. Dean HT, Jay P, Arnold FA, Jr., Elvove E. Domestic water and dental caries. II. A study of 2,832 white children, aged 12-14 years, of 8 suburban Chicago communities, including Lactobacillus acidophilus studies of 1,761 children. Public Health Rep. 1941;56(4):761-92.
3. Dean HT, Arnold FAJ, Elvove E. Domestic water and dental caries: V. Additional studies of the relation of fluoride domestic waters to dental caries experience in 4,425 white children, aged 12 to 14 years, of 13 cities in 4 states. Public Health Rep. 1942;57(32):1155-79.
4. Ast DB, Fitzgerald B. Effectiveness of water fluoridation. J Am Dent Assoc. 1962;65:581-7.
5. National Toxicology Program. NTP monograph on the state of the science concerning fluoride exposure and neurodevelopment and cognition: a systematic review. 2024 Aug. Report No.: 2330-1279 (Print) Contract No.: 8.
6. Taylor KW, Eftim SE, Sibrizzi CA, Blain RB, Magnuson K, Hartman PA, et al. Fluoride exposure and children's IQ scores: a systematic review and meta-analysis. JAMA Pediatr. 2025;179(3):282-292.
7. Levy SM. Caution needed in interpreting the evidence base on fluoride and IQ. JAMA Pediatr. 2025;179(3):231-4.
8. Do LG, Sawyer A, John Spencer A, Leary S, Kuring JK, Jones AL, et al. Early childhood exposures to fluorides and cognitive neurodevelopment: a population-based longitudinal study. J Dent Res. 2024;104(3):243-50.
9. Kumar JV, Moss ME, Liu H, Fisher-Owens S. Association between low fluoride exposure and children's intelligence: a meta-analysis relevant to community water fluoridation. Public Health. 2023;219:73-84.
10. Miranda GHN, Alvarenga MOP, Ferreira MKM, Puty B, Bittencourt LO, Fagundes NCF, et al. A systematic review and meta-analysis of the association between fluoride exposure and neurological disorders. Sci Rep. 2021;11(1):22659.
11. Iheozor-Ejiofor Z, Walsh T, Lewis SR, Riley P, Boyers D, Clarkson JE, et al. Water fluoridation for the prevention of dental caries. Cochrane Database Syst Rev. 2024;10(10):Cd010856.
12. O'Connell J, Rockell J, Ouellet J, Tomar SL, Maas W. Costs And Savings Associated With Community Water Fluoridation In The United States. Health Aff (Millwood). 2016;35(12):2224-32.
13. Meyer J, Margaritis V, Jacob M. The Impact of Water Fluoridation on Medicaid-Eligible Children and Adolescents in Alaska. J Prev. 2022;43(1):111-23.
14. Nezihovski SS, Findler M, Chackartchi T, Mann J, Haim D, Tobias G. The effect of cessation of drinking water fluoridation on dental restorations and crowns in children aged 3-5 years in Israel - a retrospective study. Isr J Health Policy Res. 2024;13(1):50.