Since the discovery of the caries preventive benefits of fluoride, it has been the cornerstone of preventive programs for children and adults. Water fluoridation, the controlled addition of a precise amount of fluoride to community water systems to the level beneficial for dental health, is one of the most effective and safe means to deliver fluoride (McDonagh et al., 2000; National Health and Medical Research Council, 2017). In 1999, the US Centers for Disease Control and Prevention (CDC) named fluoridation of drinking water as one of ten great public health achievements in the 20th Century, alongside vaccination, control of infectious diseases, a decline in death from coronary heart disease and other accomplishments (CDC, 2011). This is a remarkable recognition of the impact of dental conditions and the importance of a dental preventive program.