This paper assesses, by comparing recent published evidence with Dean's pioneering work, whether an increase in the milder forms of dental fluorosis may have occurred since Dean's time. To the extent that the crude comparisons of recent research with historic studies are valid, the data indicate a slight trend toward more fluorosis today than would be expected based upon findings in the late 1930s and early 1940s. This suggested increase in fluorosis is not as clear-cut nor as widely accepted as the recent decline in the prevalence of dental caries. Thus, further study of the prevalence of fluorosis and caries in relation to fluoride ingestion will be required to help validate the trend, and to allow dental researchers and decision makers to plan for the future.