Abstract
The purpose of this paper was to discover the relationship between the caries prevalence of the pre-school children and the salivary concentration of Streptococcus mutans using the semi-quantitative determination method (MSBB). In this method, the salivary concentration of S. mutans was showen as the degree of the adherent bacterial colony classfied score -, +, _??_ and _??_, and the resqlts of MSBB was compared with those of another test, CARIOSTAT.