1945
Historic marker commemorating water fluoridation's start in Grand Rapids, MI. Reproduced with permission from the West Michigan District Dental Society.
- Fluoridation of community water supplies began
Background
The association between fluoride in drinking water and reduction of dental caries (tooth decay) was first documented in the 1930s in communities with naturally occurring fluoride. Dr. Frederick McKay and Dr. Henry Trendly Dean developed a fluorosis index by comparing fluoride dosage rates in communities with naturally occurring fluoride to the extent of discoloration (mottled enamel) in residents’ teeth. Through this work, they established a standard of one part of fluoride per million gallons of water for reducing dental caries while avoiding discoloration.
In 1945 and 1946, independent studies of fluoride concentration ranging from negligible levels to 1.0 to 1.2 ppm to assess the effectiveness of water fluoridation were initiated in four communities in the United States and Canada (Evanston, IL; Grand Rapids, MI; Newburgh, NY; and Brantford, Ontario). Four nearby and demographically similar communities were selected for comparison. Following fluoridation for 13–15 years, the prevalence of caries decreased by 48 percent to 70 percent among children and adolescents ages 12–14 in the four communities with fluoridated water, compared with those in the communities that did not have fluoridated water.
Impact
In 2018, community water systems that contain enough fluoride to protect teeth served more than 200 million people or 73 percent of the U.S. population. Fluoridation is one of the greatest public health and disease-prevention measures of all time. Its advantages include effectiveness for all, ease of delivery, safety, equity, and low cost. Previously observed caries reductions of one-half to two-thirds are no longer attainable in the United States because other fluoride methods and products have reduced caries prevalence in all areas, thus diluting the measurement of effectiveness, and because benefits of fluoridation are dispersed in many ways to persons in nonfluoridated areas. Water fluoridation itself, however, remains as effective as it ever was among groups at high risk for dental caries. Water fluoridation also provides an important source of topical fluoride and facilitates tooth remineralization.
Sources
Allukian M (ed.). 2006. Oral Health. In Pfizer. Milestones in Public Health: Accomplishments in Public Health Over the Last 100 Years (pp. 167–189). New York, NY: Pfizer.
Center for Disease Control and Prevention. 1992. Public health focus: Fluoridation of community water systems. Morbidity and Mortality Weekly Report 41(21):372–375, 381.
Centers for Disease Control and Prevention. 2024. About Community Water Fluoridation [webpage].
Centers for Disease Control and Prevention. Water Fluoridation Reporting System [website].
Horowitz HS. 1996. The effectiveness of community water fluoridation in the United States. Journal of Public Health Dentistry 56(5):253–258.
Moss ME, Zero DT. Fluoride and Caries Prevention. In Mascarenhas AK, Okunseri C, Dye BA (eds). 2021. Burt and Eklund's Dentistry, Dental Practice, and the Community (7th ed.). St. Louis, MO: Elsevier.
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