Salivary Mutans Streptococci Counts as caries predictor in Chinese children

Objectives: This study aimed to determine whether salivary mutans streptococci (MS) counts in Chinese children had any value in the prediction of new caries in the permanent dentition in the age interval of 6.5-8.5 years. Methods: 433, 6-7-year-old children participated in this 2-year longitudinal study. Salivary MS counts were obtained with the spatula method. Spearman's correlation coefficients were calculated for exploring bi-variate associations between salivary MS counts and caries experience and between MS counts and caries increment. The past caries experience variables were entered into a multiple regression model with caries increment of the permanent dentition as dependent variables and MS counts were subsequently entered into this model. Results: Spearman's correlation coefficient for MS counts and caries experience at baseline was 0.48 and for MS counts and caries increment in the permanent dentition 0.12. In the multiple regression model caries increment of the permanent dentition had an adjusted R2 of 0.17 when the past caries experience variables were entered. Adding MS counts in the regression model did not change the R2 value. Conclusion: Salivary MS counts did not add any caries predictive value when past caries experience variables were used as caries predictors in this Chinese child population.