In a systematic review, where 214 studies were analyzed, McDonagh et al. (13) observed a decrease in the number of caries-affected teeth and an increase in dental fluorosis, depending on the fluoride intake. They also stated that the prevalence of dental fluorosis indicates that children are ingesting other sources of fluoride besides drinking water. In areas where drinking water is obtained directly from deep wells, dental fluorosis is often endemic and in many cases, the deeper the wells, the higher the fluoride concentration in drinking water.