PURPOSE: Our analysis of data collected in 1995 showed that 12-year-olds' self-esteem was associated with demographic/socioeconomic background variables and lifestyle variables and with the quality of the variable "oral health behavior." The study reported here was conducted to identify changes at ages 14 (in 1997) and 16 years (in 1999) in the strength of the association between self-esteem and "oral health behavior." METHODS: In 1995, 3370 12-year-olds answered questions about their demographic/socioeconomic background, personal attitudes/resources, and lifestyle, including "oral health behavior." Two and four years later the same study group (3105 14-year-olds in 1997 and 2836 16-year-olds in 1999) answered similar questionnaires with redefinition of "oral health behavior" as "tooth-brushing." Multivariate and logistic regression analyses were conducted using "self-esteem" and "oral health behavior/tooth-brushing" as the dependent variables. The association was also analyzed between "oral health behavior/tooth-brushing" and components of "self-esteem" (two cognitive: "How do you think your teacher would rate your school work?," "How do you think you are performing in school?," and one emotional: "How content are you with your body/looks?"). RESULTS: The association between "self-esteem" and "oral health behavior/tooth-brushing" disappeared during adolescence, but whereas the influence of cognitive components decreased, the influence of the emotional component increased. Overall, the strongest predictor of poor oral health behavior (tooth-brushing less than twice per day) was male gender. CONCLUSION: The motives for good oral health behavior changed from age 12 to age 14 years.