Prevalence and Severity of Molar Incisor Hypomineralization in Brazilian Children

The purpose of this study was to evaluate the prevalence, severity, and distribution of molar incisor hypomineralization (MIH) and its association with socioeconomic characteristics among eight-year-old students from public schools in Petrópolis, Rio de Janeiro, Brazil. This cross-sectional study evaluated 450 eight-year-old Brazilian children. A questionnaire was used to assess socioeconomic factors (family income, maternal education, and person per household). MIH was diagnosed based on European Academy of Paediatric Dentistry criteria. The severity of MIH was evaluated at patient and tooth levels. The examinations were conducted in school environments. Descriptive analysis, chi-square, Fisher's exact, and Kruskal-Wallis tests were performed. The prevalence of MIH was 28.7 percent. The average of affected molars and incisors was 2.25 (standard deviation [SD] equals 1.03) and 0.84 (1.22 SD). The maxillary molars were the most affected, but mandibular molars showed greater severity. The majority of MIH-children had white-creamy opacities (51.9 percent). There was no association between MIH and socioeconomic factors. MIH was more prevalent in boys (P=0.025). The number of incisors with MIH rose with the increasing number of affected molars (P=0.02). A significant association between severity and the mean number of affected molars was observed (P=0.004). The prevalence of molar incisor hypomineralization was 28.7 percent. MIH severity at the individual level was significantly associated with the number of affected teeth and the occurrence of affected incisors.