Streptococcus mutans in saliva: intraindividual variations and relation to the number of colonized sites.

Analysis of the salivary levels of Streptococcus mutans may contribute to the evaluation of the caries risk. It is therefore important to identify factors that might influence the outcome of such analyses. This investigation consisted of three parts. The first aim was to evaluate the short-term variation of S. mutans concentration in saliva. Furthermore, we estimated the effect of discontinued oral hygiene on salivary S. mutans. We also analyzed the relation between salivary levels of S. mutans and the number of colonized approximal and occlusal sites. Tongue samples were also included in the comparison. Systematic short-term variation could not be demonstrated. A 95% confidence interval for an observed S. mutans value was obtained by multiplying and dividing the observed value by a factor of 5 (for S. mutans samples less than 10(6) or 2.3 (S. mutans greater than 10(6). One week of discontinued oral hygiene did not significantly change the level of S. mutans in saliva. Saliva samples correlated significantly with tongue samples and with the number of colonized approximal sites. The results of these studies confirm the stability of the S. mutans colonization level.