AADR supports community water fluoridation as a safe and effective, evidence-based intervention for the prevention of dental caries. While fluoride occurs naturally in water, fluoridation is the controlled addition of fluoride to community water systems to the level recommended for caries prevention. The practice of adding fluoride to community water supplies began after Dr. H. Trendley Dean – the first director of what later became the National Institute of Dental and Craniofacial Research – observed that residents of communities who drank from naturally fluoridated water supplies experienced less tooth decay than those living in communities without naturally fluoridated water.  What began as a small trial of the controlled addition of fluoride to water in Grand Rapids, Michigan has now reached 75% of the United States population who drink from a community water system and has resulted in a significant decrease in dental caries.1, 2

Dental caries – the destruction of dental hard tissues – can result in pain, infection and tooth loss. Caries is caused by acidic byproducts produced from bacterial fermentation of sugar. Dental caries is a very common disease that affects both adults and children. Over one-third of children ages 2-8 experience caries in their primary teeth. One in 5 children ages 6-11 and over half of adolescents ages 12-19 experience caries in their permanent teeth. On average older adults can expect at least one new decayed tooth surface per year.  Children with poor oral health are more likely to miss school and suffer academically. Parents may also accrue absences from school or work to seek treatment for their children. Both children and adults with caries may experience embarrassment, exhibit withdrawal, have difficulty eating and sleeping, and limit facial expressions and behaviors that facilitate social interaction. 3-9

Many studies point to the effectiveness of community water fluoridation in decreasing dental caries. A systematic review of 20 studies by Cochrane, an independent group that reviews medical research to inform evidence-based policies and health guidelines, showed that water fluoridation decreased tooth decay in both the primary and permanent teeth of children and increased the number of children free of decay in primary and permanent teeth.10, 11* Another review by the Community Preventive Services Task Force (CPSTF), an independent panel of public health experts appointed by the Director of the Centers for Disease Control and Prevention (CDC), found that starting water fluoridation decreased caries in children ages 4-17 by 30-50% and that stopping water fluoridation increased caries by 18%. 12 Furthermore, reducing childhood caries experience and severity may have benefits into adulthood by halting disease progression that can result in adult tooth loss. Lifelong exposure to fluoridated water has been associated with reduced tooth decay in adults.13, 14

Community water fluoridation is a cost-effective method of delivering caries prevention to a large population. A systematic review by the CPSTF compared the cost of fluoridation to the money saved on dental restorations in communities that drink from fluoridated water sources. CPSTF found that water fluoridation is cost saving. In other words, the savings from fewer dental restorations are greater than the cost of fluoridation for communities of greater than 1,000 people, and the larger the community, the greater the cost saving.15 A 2016 analysis confirmed this finding.16

Community water fluoridation may also reduce oral health disparities. Children and adults from socioeconomically disadvantaged backgrounds are more likely to suffer from dental caries and are less likely to be treated for the disease.6, 17  When added to drinking water, fluoride can be delivered to community residents regardless of socioeconomic status or ability to access dental services. Some studies have shown decreased inequalities in caries in communities that drink from a fluoridated community water source, revealing  that children of a lower socioeconomic status who have access to a fluoridated water source have less severe tooth decay and require less expensive care than children of lower socioeconomic status who do not drink fluoridated water. More research is needed to determine the circumstances in which water fluoridation reduces disparities, as not all fluoridated communities show reduced disparities.10, 18

Community water fluoridation is a safe method of delivering fluoride on a population level. There have been numerous systematic reviews on claims of the potential adverse health effects of water fluoridation. None has concluded that there is a significant or consistent association between water fluoridation and the outcomes examined, including neurologic conditions, cancer or osteoporosis.19-23  Dental fluorosis resulting in tooth discoloration is the only known adverse health effect of water fluoridation. Teeth are only at risk of fluorosis until about age 8 during enamel formation. The United States Public Health Service recommends a concentration of 0.7 milligrams of fluoride per liter of water to achieve caries prevention while minimizing the risk of dental fluorosis.24 While people who drink from fluoridated water sources are at greater risk of dental fluorosis, most people who drink fluoridated water do not develop dental fluorosis.  The cases of dental fluorosis that do develop are very mild, such that discoloration is not usually visible to the naked eye and does not affect the function of the teeth. Severe cases of dental fluorosis are rare. Some studies have shown that Black/African-American and Mexican-American children are at greater risk of developing dental fluorosis. However, this has not been clearly linked to fluoridated water and may be due to cumulative fluoride intake from various sources, such as toothpaste, supplements and food and beverages prepared with fluoridated water.10, 17, 25

Community water fluoridation is supported by various groups, including the American Association of Public Health Dentistry, the American Public Health Association, the American Dental Association and the American Academy of Pediatrics, among others. Additionally, in 1999, the CDC identified community water fluoridation as one of 10 great public health achievements of the 20th century because of its effectiveness and ability to distribute fluoride equitably and cost-effectively.26 Information about the fluoride concentration of communities participating in water fluoridation can be found on the CDC website “My Water’s Fluoride”.27

While AADR always welcomes research on water fluoridation safety and effectiveness in the current context of fluoride availability, the balance of evidence currently shows that community water fluoridation is safe, effective and cost-saving and in some communities, reduces oral health disparities. Therefore, AADR supports community water fluoridation and recommends the fluoridation of community water sources to a level of 0.7 milligrams of fluoride per liter of water.


*The authors of the Cochrane systematic review determined that the evidence for community water fluoridation for the prevention of dental caries was low quality and that many studies were conducted before 1975. The Cochrane review method considers randomized clinical trials as the gold standard of evidence and automatically rates common methods for evaluating public health interventions as low. However, randomized trials are usually not feasible for interventions at the population level. The authors noted this gap in their evidence grading system and that the evidence pointed in the same direction of fluoridation reducing tooth decay.

References

  1. Centers for Disease Control and Prevention. Water Fluoridation Basics. Atlanta: Centers for Disease Control and Prevention, US Department of Health and Human Services; [accessed 8 September 2017]. https://www.cdc.gov/fluoridation/basics/index.htm.
  2. Gutmann JL. The Evolution of America's Scientific Advancements in Dentistry in the Past 150 Years. The Journal of the American Dental Association. 140:11S-15S.
  3. Low W, Tan S, Schwartz S. 1999. The effect of severe caries on the quality of life in young children. Pediatr Dent. 21(6):325-326.
  4. Seirawan H, Faust S, Mulligan R. 2012. The Impact of Oral Health on the Academic Performance of Disadvantaged Children. American Journal of Public Health. 102(9):1729-1734.
  5. Jackson SL, Vann WF, Kotch JB, Pahel BT, Lee JY. 2011. Impact of Poor Oral Health on Children's School Attendance and Performance. American Journal of Public Health. 101(10):1900-1906.
  6. Griffin SO, Jones JA, Brunson D, Griffin PM, Bailey WD. 2012. Burden of Oral Disease Among Older Adults and Implications for Public Health Priorities. American Journal of Public Health. 102(3):411-418.
  7. Griffin SO, Griffin PM, Swann JL, Zlobin N. 2004. Estimating Rates of New Root Caries in Older Adults. Journal of Dental Research. 83(8):634-638.
  8. Griffin SO, Griffin PM, Swann JL, Zlobin N. 2005. New Coronal Caries in Older Adults: Implications for Prevention. Journal of Dental Research. 84(8):715-720.
  9. Dye B, Thornton-Evans G, Li X, Iafolla T. 2015. Dental caries and sealant prevalence in children and adolescents in the United States, 2011-2012.  NCHS Data Brief, no. 191. Hyattsville, MD: National Center for Health Statistics.
  10. Iheozor-Ejiofor Z, Worthington HV, Walsh T, O'Malley L, Clarkson JE, Macey R, Alam R, Tugwell P, Welch V, Glenny A-M. 2015. Water fluoridation for the prevention of dental caries. Cochrane Database of Systematic Reviews. (6).
  11. Rugg-Gunn AJ, Spencer AJ, Whelton HP, Jones C, Beal JF, Castle P, Cooney PV, Johnson J, Kelly MP, Lennon MA et al. 2016. Critique of the review of 'Water fluoridation for the prevention of dental caries' published by the Cochrane Collaboration in 2015. Br Dent J. 220(7):335-340.
  12. Truman BI, Gooch BF, Sulemana I, Gift HC, Horowitz AM, Evans CA, Jr., Griffin SO, Carande-Kulis VG. 2002. Reviews of evidence on interventions to prevent dental caries, oral and pharyngeal cancers, and sports-related craniofacial injuries. American Journal of Preventive Medicine. 23(1):21-54.
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  15. Ran T, Chattopadhyay SK. Economic Evaluation of Community Water Fluoridation. American Journal of Preventive Medicine. 50(6):790-796.
  16. O’Connell J, Rockell J, Ouellet J, Tomar SL, Maas W. 2016. Costs And Savings Associated With Community Water Fluoridation In The United States. Health Affairs. 35(12):2224-2232.
  17. Beltrán-Aguilar ED, Barker LK, Canto MT, Dye BA, Gooch BF, Griffin SO, Hyman J, Jaramillo F, Kingman A, NowjackRaymer R et al. 2005. Surveillance for Dental Caries, Dental Sealants, Tooth Retention, Edentulism, and Enamel Fluorosis United States, 1988-1994 and 1999-2002. Surveillance Summaries. 54(03):1-44.
  18. Burt BA. 2002. Fluoridation and Social Equity. Journal of Public Health Dentistry. 62(4):195-200.
  19. McDonagh MS, Whiting PF, Wilson PM, Sutton AJ, Chestnutt I, Cooper J, Misso K, Bradley M, Treasure E, Kleijnen J. 2000. Systematic review of water fluoridation. BMJ. 321:855-859.
  20. Jones G, Riley M, Couper D, Dwyer T. 1999. Water fluoridation, bone mass and fracture: a quantitative overview of the literature. Australian and New Zealand Journal of Public Health. 23(1):34-40.
  21. Demos LL, Kazda H, Cicuttini FM, Sinclair MI, Fairley CK. 2001. Water fluoridation, osteoporosis, fractures—recent developments. Australian Dental Journal. 46(2):80-87.
  22. Whiting P, McDonagh M, Kleijnen J. 2001. Association of Down's syndrome and water fluoride level: a systematic review of the evidence. BMC Public Health. 1(1):6.
  23. Agency for Toxic Substances and Disease Registry (ATSDR). 2001. Toxicological profile for Fluorides, Hydrogen Fluoride, and Fluorine. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service. 
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  25. Martinez-Mier EA, Soto-Rojas AE. 2010. Differences in exposure and biological markers of fluoride among White and African American children. Journal of Public Health Dentistry. 70(3):234-240.
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(adopted 2018)