Dental fluorosis is a disturbing condition where white or brown spots and streaks appear on teeth. It is typically believed to occur from high fluoride exposure, however, in this 2021 study from Peking Union Medical College, researchers found exposure to even normal levels of fluoride typical in treated water systems was increasing dental fluorosis as well. Of the 2,098 U.S. children involved in the study, those whose drinking water contained fluoride at levels up to 0.51 to 0.70 mg/L (with 0.70 mg/L being typical for treated water) had a 92% greater chance of dental fluorosis than children whose water contained levels typical in non-fluoridated communities (less than 0.03 mg/L). Why child fluorosis could be elevated in fluoridated water systems is explained below.
Higher blood fluoride levels in some children could be explained by the fact that kidneys are the main organ for blood fluoride removal. As some children have significantly less kidney filtration and efficiency than others, this could be a plausible explanation for the discrepancy. Scientists also stated blood levels showed higher levels of fluoride in children than adolescents. In fact, the authors stated that because of this discrepancy, and more detrimental fluoride effects in younger children, they should be given alternative sources of drinking water.
This study suggests that scarring of teeth into adulthood from the addition of fluoride to water systems is to be expected in homes where fluoride is added to water supplies and could psychologically and financially impact many individuals.
ABSTRACT
Drinking water fluoridation was a mid-twentieth century innovation based on the medical hypothesis that consuming low doses of fluoride at the teeth forming years provided protection against dental decays. Numerous studies showed that high level exposure to fluoride could cause dental and skeleton fluorosis. However, there was limited study focusing on the fluorosis effect of low levels of exposure to fluoride. Therefore, our study aimed to examine whether the low level of fluoride exposure (measured in blood plasma and household tap water) was associated with the risk of dental fluorosis based on data of the National Health and Nutrition Examination Survey (NHANES) 2015–2016. We analyzed data in 2098 children and adolescents who had Dean's Index scores, and water and plasma fluoride measures. The Dean's Index score was measured by calibrated dental examiners using the modified Dean's fluorosis classification system. Fluoride was measured in plasma and household tap water. In this study, we found that the rate of fluoride concentration in water above the recommended level of 0.7 mg/L was 25%, but the prevalence of dental fluorosis was 70%. Binary logistic regression adjusted for covariates showed that higher water fluoride concentrations (0.31–0.50, 0.51–0.70, > 0.70 compared 0.00–0.30) were associated with higher odds of dental fluorosis (OR = 1.48, 95% CI: 1.13–1.96, p = 0.005; OR = 1.92, 95% CI: 1.44–2.58, p < 0.001, and OR = 2.30, 95% CI: 1.75–3.07, p < 0.001, respectively). The pattern of regression between plasma fluoride and dental fluorosis was similar. Inclusion, our study showed that even low level of water or plasma fluoride exposure was associated with increased the risk of dental fluorosis. The safety of public health approach of drinking water fluoridation for global dental caries reduction are urgently needed further research.