In our study, there were prevalences of S mutans of 80% in group 1, 75% in group 2, and 70% in group 3 before the study began. These values were similar to earlier studies that showed prevalences greater than 60%. After 30 days, the prevalence of S mutans in group 1 remained the almost the same at 93.75%, but there were decreases in S mutans in almost all subjects in groups 2 and 3; this was similar to the results of previous studies. After use of the probiotic curd and the toothpaste, almost all subjects in groups 2 and 3 showed a reduction in the S mutans levels; in some subjects, there were no detectable S mutans streptococci mutans after 30 days. This decrease was almost more than 2-fold in both groups 2 and 3.