Presence of Streptococcus mutans or Streptococcus sobrinus in Cariostat®-inoculated plaque samples from Japanese mother-child pairs

The aim of this study was to determine the presence of Streptococcus mutans or Streptococcus sobrinus in Cariostat-inoculated plaque samples obtained from Japanese mother-child pairs through a conventional PCR technique and to establish the presence of these bacteria and caries risk. Oral examination and caries risk assessment using the Cariostat® were carried out on 168 children, aged 6-31 months, and their mothers. The presence of S. mutans and S. sobrinus in Cariostat-inoculated plaque samples was checked through PCR and tested for relevance with caries risk. A significant correlation (P < 0.001) was found between caries risk of mothers and presence of S. mutans or S. sobrinus in plaque samples from their children in the 19-31-month-old age range. However, no significant relationship found between the presence of either strain in the plaque of younger children (6-18 months) and caries risk of mothers. Likewise, high caries risk was seen in 49.1% of the 19-31-month-old children of highrisk mothers (P < 0.001) and 27% of the 6-18-month-old children of high-risk mothers (P < 0.05). The effectiveness of the Cariostat method for prediction of caries risk can be improved by detecting the presence of S. mutans and S. sobrinus in plaque samples obtained from mothers and their children through conventional PCR techniques.