A Longitudinal Study on Dental Caries Focusing on Long-Term Breastfed Children in Japan

Background/Objectives: Although the relationship between prolonged breastfeeding and early childhood caries remains unclear, dentists must manage children's oral health while respecting mothers' chosen feeding practices and providing information on maintaining oral health as long as possible. This longitudinal study was performed to investigate the occurrence of dental caries and identify associated factors, with particular attention to maternal condition and oral-health-related support in long-term breastfed children. Methods: Of 6746 children aged 42 months in Toyonaka City, Japan, 1210 who had been breastfed for at least the first 18 months were enrolled. Participants underwent oral examinations and anthropometric measurements at 18 and 42 months of age. In addition, a self-administered questionnaire was distributed to families when the child was 18 months old. Logistic regression analysis was used to evaluate risk factors for dental caries, with caries occurrence at 42 months as the dependent variable. Results: Overall, 24.3% of the children had experienced dental caries at 42 months. Logistic regression analysis identified several significant factors associated with caries occurrence: birth order (p < 0.001), snacking frequency (p = 0.038), Cariostat^® caries-risk test results (p < 0.001), and wake-up time (p = 0.015) among child factors, and parental exhaustion (p = 0.041) and participation in postnatal oral health classes (p = 0.005) among maternal factors. Conclusions: Waking habits in early childhood, maternal psychological condition, and participation in postnatal oral health instruction were significantly associated with dental caries occurrence over time among long-term breastfed children.