[Dynamic and quantitative analysis of cariogenic bacteria and its proportion in the dental plaque of different caries-susceptible children].

Purpose: To investigate the ratio and change of bacteria in dental plaque in different caries-susceptible children.

Methods: Dental plaques were obtained from 60 children of 3-5 years old. Four targeted cariogenic bacteria were quantitatively detected by real-time PCR and the mean dmft score was calculated. The effectiveness was assessed and compared using SASS.17 software package.

Results: The decayed missing filled surfaces(dmfs) score and the percentages of cariogenic bacteria at 1 year increased significantly(P<0.01). There were significant differences in percentages of S.mutans and S.sobrinus in early childhood caries group and severe early childhood caries group between baseline and at 1 year (P<0.01). There was linear correlation between dmfs score and the sum of the percentages of S.mutans and S.sobrinus at baseline and 1 year.

Conclusions: The ratios of cariogenic bacteria to total bacteria in plaque are closely associated with the prevalence of dental caries in children. The higher proportion of cariogenic bacteria, the higher susceptibility of subjects with early childhood caries. Supported by National Natural Science Foundation of China (81371158) and Special Research Fund for Health Care Industry (201002017).