Risk factors for dental fluorosis: a review of the recent literature

The decline in dental caries prevalence and incidence in developed countries over the last two decades is considered to be largely due to the widespread use of fluoride. Simultaneously, with the decline in caries, an increase in the prevalence of dental fluorosis has been noticed. The increase is in the mild and very mild forms of fluorosis, and is proportionally greater in non-fluoridated areas than in fluoridated areas. This is because of the increase in the mean fluoride intake from all sources since the 1940s. The increase in fluorosis prevalence prompted numerous studies on risk factors for fluorosis. As a result the literature over the last two decades has also reported numerous studies with differing and confusing results. This paper describes for the clinician the condition and summarizes the recent literature on the risk factors for fluorosis. Only well conducted studies evaluating risk factors or indicators and quantifying the risk for dental fluorosis from the 1980s through the 1990s time period were included in this review. Four major risk factors were consistently identified: use of fluoridated drinking water, fluoride supplements, fluoride toothpaste, and infant formulas before the age of six years.