Risk behaviors and their association with presence of S.mutans or S.sobrinus and caries activity in 18-month-old Japanese children

The purpose of this study was to investigate risk behaviors associated with the presence of S. mutans or S. sobrinus and caries activity. The subjects were 448 mother-child pairs who underwent dental health examinations between February 2004 and November 2004 when the children were 18 months old. Caries activity was assessed by the Cariostat test. The presence of S. mutans and S. sobrinus was detected using PCR techniques. Questionnaires regarding risk behaviors were completed by the mothers. A statistically significant correlation was found for the detection of S. mutans and/or S. sobrinus in children and mothers (P < 0.01). High-risk mothers were more likely to have high-risk children (P < 0.001). In children in whom bacteria were detected, breast-feeding was ranked as the most important risk factor (P < 0.01), followed by eating snacks while playing (P < 0.01), getting snacks from neighbors (P < 0.05), being cared for by grandparents (P < 0.05) and pre-chewing of children's food by mothers (P < 0.05). In children with high caries risk, breast-feeding and pre-chewing were the most important risk factors (P < 0.01), followed by taking meals at irregular intervals and mothers not attending maternity classes (P < 0.05).