OBJECTIVE To analyse trends in the prevalence of and determinants for dental care utilisation among Finnish adults of working age during two decades. METHODS The National Public Health Institute has, since 1978, conducted annual surveys of health behaviour among the whole Finnish adult population (aged 15-64 years). Data collected through mailed questionnaires have included questions on dental utilisation. Sample sizes have varied from 5,000 to 6,000 and response rates from 68% to 85%. RESULTS The use of dental services increased in the period 1978 to 1997 from 53% to 64% (P<0.001) of the population. Women and persons belonging to the younger age groups were the most frequent visitors, and older persons the least frequent due to the greater prevalence of edentulousness. During the period, differences in the use of services associated with region, level of education and occupation declined. During the first decade, a clear increase in dental utilisation was found in younger age groups and during the latter decade in older age groups. Significant predictors for the utilisation of services were the number of missing teeth, age, gender, occupation and toothbrushing frequency in 1997. CONCLUSIONS The utilisation of dental services has increased slowly since 1978 but remains lower than in other Nordic countries. In a country where the supply of services is abundant, the major determinant of the use of services is the number of teeth an individual has.