Water fluoridation is supported by a robust body of evidence. Numerous epidemiological studies have demonstrated significant reductions in cavities in communities with fluoridated water. The effect is most pronounced in populations with limited access to dental care, especially if they choose not to use fluoridated toothpaste. In more affluent areas, and when fluoride toothpaste is used, the incremental benefits of water fluoridation are smaller.

What about risks? ... Allegations linking fluoride to cancer, thyroid dysfunction, and neurological issues lack strong evidence. A 2006 report by the US National Research Council recommended lowering the maximum allowable fluoride concentration in drinking water to 2 ppm -- not because of new health concerns but to prevent severe fluorosis in areas with naturally high fluoride levels.

One of the most controversial claims is that fluoridation impacts intelligence. A 2019 study in JAMA Pediatrics suggested a correlation between maternal fluoride intake during pregnancy and slightly lower IQ scores in male children. However, the study relied on estimates of fluoride consumption and failed to account for critical variables like maternal IQ and environmental pollutants. Moreover, subsequent analyses have challenged its conclusions, suggesting that if an effect exists, it is minor and likely insignificant compared to other prenatal risks, such as tobacco smoke, lead exposure, and, indeed, maternal dental caries.

As Paracelsus, the father of toxicology, famously said, "The dose makes the poison."