Purpose: To investigate and analyze the prevalence and severity of molar-incisor hypomineralization(MIH) among children from 6 to 11 years old in Lucheng district of Wenzhou city.
Methods: Children aged 6 to 11 years (n=988) with all four-first permanent molars erupted were evaluated according to the European Academy of Paediatric Dentistry (EAPD) criteria. Examiners recorded the severity and position of each tooth diagnosed with MIH. SPSS 13.0 software package was used for analyze. Kruskal-Wallis test was used to determine the differences in the defect severity among different ages and the difference in the prevalence of MIH between the upper and lower molars or between the upper and lower incisors. Spearman test was used to test the association of the MIH-defect severity with the age of children.
Results: Molar-incisor hypomineralization was present in 25.5% of the 988 children, and the majority of the defects presented were mild. There were significant differences among the six age groups with the severity of MIH (P<0.05), but no significant difference was found in the distribution of the MIH defect between the maxilla and the mandible (P>0.05). The severity of MIH increased along with the aging of children (rp=0.534).
Conclusions: Despite the high prevalence of MIH, the severity of the defects was mild. The results indicate a positive association between the severity of MIH and the age of children.