Dentists' selection of measures for assessing oral health risk factors for young adults, in relation to their oral health status and to those dentists' characteristics, was studied in one administrative unit of the Finnish public oral health service. A random selection (n = 239) was made of all young adults born in the period 1966-71 and clinically examined during 1994. On the original oral health records of those selected, all notes were scrutinized concerning the most recent clinical examination and treatment course; in total 208 (87%) records. We found that assessment of risk factors to oral health was rare. The patient's diet had been recorded as assessed in 7% of all cases, use of fluoride in 8%, and oral hygiene habits in 14%. No salivary tests were performed; nor was patients' use of tobacco assessed. No correlation was detected between measures used by these dentists and their patients' oral health status (DMFT and DT scores, number of approximal incipient lesions, and number of healthy sextants by CPITN). The oral health status impelled only slightly assessments by bite-wing radiographs. Fewer than half (44%) of the dentists performed and recorded any kind of assessment measure; 4% assessed diet, hygiene, and use of fluoride for all their patients in our sample. A dentist's gender showed no correlation with number of measures used; younger dentists tended to perform and record assessments slightly more often than did older dentists, but in all age groups there were those who had not done this. The practice of risk-factor assessment should be more widespread and standardized, contributing to needs-based treatment and allocation of resources.