Prevalence and Cause of Enamel Hypoplasia in Primary Teeth among 1-year-old Japanese Children

Objective: In this study, the prevalence and underlying cause of enamel hypoplasia in one-year-old children were examined. Additionally, to determine the association between enamel hypoplasia and exposure to sunlight based on the frequency of the mother’s outings during pregnancy. Methods: A total of 273 kids (139 boys) were involved in this study. Based on questionnaires surveys to mothers, oral examinations, and photographs of children's mouths, we looked at the connection between the circumstances of pregnancy and the occurrence of enamel hypoplasia. The presence of enamel hypoplasia was assessed using logistic regression analysis differed among the results of the questionnaire. Results: The prevalence of enamel hypoplasia was 38.5%. In the medium and low groups, enamel hypoplasia was more common than in the high group at the birth month of the child (adjusted odds ratio: 3.36, 95% confidence interval: 1.65–6.85, p = 0.001 vs. adjusted odds ratio: 3.76, 95% confidence interval: 1.89–7.48, p < 0.001, respectively). Enamel hypoplasia was knowingly higher among the children whose mothers went out less than 1–2 times a week during pregnancy (adjusted odds ratio: 2.41, 95% confidence interval: 1.04–5.61, p = 0.041). Enamel hypoplasia was significantly more prevalent when mothers used painkillers during pregnancy (adjusted odds ratio: 5.45, 95% Confidence interval: 1.74–17.08, p = 0.004). Conclusion: It was suggested that the use of antipyretic analgesics during pregnancy and frequency of outings and variations in sunshine hours according to the child's birth month could affect the occurrence of enamel hypoplasia.