Environmental epidemiology is a field replete with controversies, but the intensity of the debate inspired by the fluoridation of municipal water supplies to reduce dental caries is perhaps unrivaled. Governments, as well as individuals, differ in their assessments of water fluoridation as public policy. The US Centers for Disease Control and Prevention consider water fluoridation to be one of the top 10 public health achievements in the 20th century,1 reducing both overall caries prevalence and socioeconomic disparities.2 Regions in which water fluoridation is rare, such as Europe, rely on more targeted strategies to deliver fluoride (eg, supplements, dental treatments and products, fortification of milk and salt). Notably, in most Western European countries, the prevalence of decayed, missing, or filled teeth is similar to or lower than the prevalence in the United States.3