Is there an association between molar-incisor hypomineralization and carious lesions in seven to ten-year-old Brazilian schoolchildren? A cross-sectional study.

Objective: To evaluate whether the presence of molar-incisor hypomineralization (MIH) is associated with a greater number of decayed teeth in schoolchildren.

Methodology: A cross-sectional study was conducted with a random sample of 347 children aged from seven to ten years in the Brazilian city of Diamantina. The International Caries Detection and Assessment System (ICDAS) criteria were used to determine the number of teeth with moderate/extensive caries (ICDAS codes 3-6). MIH was assessed according to the criteria of the European Academy of Paediatric Dentistry (EAPD). Sociodemographic data and data regarding children's habits were obtained via a questionnaire sent to parents/guardians. Descriptive analyses, Mann Whitney and Kruskal Wallis tests, and Poisson regression were performed.

Results: The prevalence of MIH was 20.5% and that of moderate/extensive caries was 39.2%. The mean number of teeth with moderate/extensive caries was 1.80 (SD±2.67). The mean number of decayed permanent teeth was 0.69 (SD=1.21), and the mean number of decayed primary teeth was 1.11 (SD=1.89). The number of teeth with moderate/extensive caries was associated with the presence of MIH in children (PR=1.45; 95% CI=1.03-2.04; p=0.031). Furthermore, the number of teeth with moderate/extensive caries was associated with lower monthly family income, high frequency of sugar consumption, and visible plaque (p<0.05).

Conclusion: The presence of MIH is associated with a greater number of decayed teeth in schoolchildren.

Clinical relevance: This study suggests that children with MIH are at higher risk of developing caries, emphasizing the importance of specific preventive care and early treatments for this condition. This can influence clinical practices, public health policies, and parental education.