Real-time PCR analysis of cariogenic bacteria in supragingival plaque biofilm microflora on caries lesions of children

The aim of this study was to quantify cariogenic bacteria, Streptococcus mutans, in supragingival plaque biofilm microflora on caries lesions of children. After informed consent was obtained from each subject, supragingival plaque on caries lesion was obtained from 10 children (3–10 years). Healthy supragingival plaque was also obtained from the same subject, as a control. Total bacteria and S. mutans were quantified by real-time PCR using universal and S. mutans-specific primers based on 16S ribosomal RNA genes, respectively, and the proportion of S. mutans in each sample was calculated. Total bacterial DNA levels in carious plaque and healthy plaque were found to be similar, though the proportion of S. mutans in carious plaque was higher than that in healthy plaque. The findings of this study suggest that amount of cariogenic bacteria in supragingival plaque biofilm may be associated with the status of dental caries.