. Our finding that a history of brushing more than once per day beginning during the first 2 years was strongly associated with mild-to-moderate enamel fluorosis represents the first epidemiologic evidence that early toothbrushing habits are strongly and statistically significantly associated with mild-to-moderate enamel fluorosis in children growing up in nonfluoridated areas These findings are consistent with our previous findings (22) in a pre-1980 birth cohort of children who grew up in fluoridated communities, where frequent brushing throughout the first 8 years was found to be strongly associated with mild-to-moderate