Recent studies indicate that the prevalence of very mild to moderate dental fluorosis, as classified by Dean, has increased relative to that found in earlier investigations. To date, fluoridated water, fluoride supplements, the diet, fluoride dentifrices, and other topical fluoride applications have been identified as sources of systemic fluoride. Recent evidence suggests that there is a strong association between mild to moderate enamel fluorosis and the use of fluoride supplements during early childhood, and that the presently recommended supplementation schedule for U.S. children above the age of 2 years may be too high. Evidence also suggests that there is a strong association between fluoride dentifrice use during early childhood and enamel fluorosis in fluoridated populations. These findings support the need for a careful review of existing supplementation schedules and early oral hygiene practices. There is a pressing need for additional analytical epidemiological studies to confirm existing findings and to determine whether other fluoride sources may be associated with enamel fluorosis. Further, since exposure to combinations of individual risk factors has been shown to carry more than merely an additive increase in the risk of fluorosis, these studies must be multifactorial in design. There is also a need for more fluorosis prevalence and severity data to be gathered, so that the development of enamel fluorosis as a public health problem can be assessed, and so that the success of measures implemented to maximize efficacy while minimizing unwanted side-effects can be monitored.