As an oral health advocate and practicing dentist for more than 40 years, I am deeply concerned by a recent story on the Public Radio International (PRI) show "Living on Earth." The story, entitled "Health Risks of Water Fluoridation Raise Concerns," represented an incomplete view of water fluoridation that gives the false impression that there is little or no recent research to support this public health practice.
In fact, the U.S. Department of Health and Human Services Federal Panel on Community Water Fluoridation reported in 2015 their review of the evidence supporting what the Centers for Disease Control and Prevention (CDC) has described as one of 10 great public health achievements of the 20th century. More than 70 years of the best available scientific evidence shows community water fluoridation is safe, effective, and economical in preventing tooth decay.
Howard Pollick, BDS, MPH, is a health sciences clinical professor at the University of California, San Francisco School of Dentistry and a member of the American Dental Association’s National Fluoridation Advisory Committee.The story mentioned the research of Philippe Grandjean, MD, which actually showed that while higher levels of fluoride have been associated with IQ, lower levels of community water fluoridation, such as the optimal level in the U.S., have no effect on IQ. Despite Dr. Grandjean's claim that the fluoride levels were "just a bit" different from those in the U.S., they were actually double or triple and higher than the concentration in U.S. water systems. In addition, British researchers who evaluated these studies from China and other countries found "basic errors." These researchers pointed out that the lower IQs could be traced to other factors, such as arsenic exposure and the burning of high-fluoride coal inside homes.
Stephen Peckham, a professor of health policy from the University of Kent in the U.K., stated in the story that he and his colleagues "found an association or a risk, of higher levels of hypothyroidism in practices in fluoridated areas."
However, Peckham's study has recently been criticized for containing serious biases and flaws with the recommendation that "the paper's conclusions can and should be dismissed." Similarly, another critical review of Peckham's article found that "this study provides no evidence of a causal relationship between water fluoride concentration and hypothyroidism."
The story mentioned the Cochrane Collaboration review findings on fluoridation, which were shaped by its unusually narrow inclusion criteria, excluding 97% of the more than 4,000 relevant studies that it identified, including many published in reputable, peer-reviewed journals. The authors of the Cochrane review acknowledged significant limitations, saying there is much debate around the approach used to assess the quality of evidence within their review when applied to public health interventions, particularly for research questions where evidence from randomized controlled trials will never be available. Nevertheless, they did conclude that there were fewer teeth affected by cavities and a higher percentage of caries-free children in fluoridated communities, findings that are similar to other evidence-based reviews.
One of the interviewees, Laura Turner Seydel, discussed a link between water fluoridation and dental fluorosis, but there is no evidence that fluoridated water causes severe dental fluorosis. Seydel misinterprets the facts with regard to her statement that 1 out of 3 African-Americans have a condition called dental fluorosis, the pitting and discoloring of enamel.
Additionally, the caption under the photograph of teeth with severe fluorosis inaccurately states: "Dental fluorosis is pitting and discoloration of tooth enamel, and can be caused by drinking fluoridated water." In fact, pitting of enamel indicates a severe level of enamel fluorosis, which is not seen in fluoridated communities. The 2015 review by the U.S. Federal Panel on Community Water Fluoridation also recommended standardizing the concentration of fluoride in drinking water to the lowest end of the previous range of 0.7 to 1.2 parts per million, in part to reduce future prevalence of the milder forms of dental fluorosis.
We must continue to educate the public about the facts of fluoride. For more information, visit ADA.org/fluoride.
Howard Pollick, BDS, MPH, is a health sciences clinical professor at the University of California, San Francisco School of Dentistry and a member of the American Dental Association’s National Fluoridation Advisory Committee.
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