Data summarising caries levels differ between countries and often conceal large variations. These differences may reflect variations at individual, group, social and other levels. Caries and treatment experience differences are found to be significantly related to a variety of clinical and non-clinical factors. Variation in caries within Lithuanian children has been reported and related to background-, behavior-, dental care- and other factors. Variation in general or related to any factors in adult Lithuanian population has not been studied. The aim of the present study was to estimate variation in caries and treatment experience and relate them to biological-, psychosocial-, health-related, behavioral- and dental care related aspects. The existing knowledge from other oral health studies was used to select the factors found of importance in relation to variations in caries scores. The study consisted of clinical and self-reported data collected from a stratified random sample of 382 individuals (attendance rate 50%). Two statistical approaches, a bivariate and a multivariate, were applied. The two dependent variables DMFT and DS were tested with a set of independent variables. The bivariate analysis revealed significant associations for approximately one half of all variables studied. For multivariate testing, a backward linear multiple regression was used. Forty-one percent of the variation in DS was explained and 48% in DMFT scores. Differences in scores were related to various factors in the two analyses. The strength and significance of a few relationships differed in both of the analyses. The multivariate testing revealed some strong and significant associations with independent variables which were found to be weak and non-significant (P>0.05) when tested bivariately and vice versa. Less than half of the variation could be explained in dental caries scores in 35-44-year-olds and not only dental care related factors were important. In both of the analyses, the varying degrees of strength (significance levels) give rise to a hypothesis that this incomplete explanation of the variation can be due to interrelated effects of different estimates.