Prevalence of MIH in children aged 12 to 15 years in Beijing, China.

To investigate the prevalence of molar-incisor hypomineralization (MIH) in children aged 12 to 15 years in Beijing, China. A cross-sectional study was performed to recruit children aged 12 to 15 years old based on the method of multi-stage cluster random sampling during the Fourth National Oral Health Survey in Beijing, China, from September 2015 to March 2016. The first permanent molars (FPMs) and permanent incisors were examined for the presence of MIH by a single-calibrated examiner according to the European Academy of Paediatric Dentistry (EAPD) criteria. Of the 6523 children recruited, 655 (10.0%) had MIH. The average number of affected MIH teeth in children was 2.68 ± 1.51. There was no gender-specific difference. With respect to the distribution of MIH in the mandible and maxilla, the most common condition was the simultaneous involvement of both the upper and lower FPMs. The severity of MIH was positively correlated with the number of affected teeth. The prevalence of MIH was lower in children who resided in the central districts and whose mothers had received higher education. MIH was relatively prevalent among children aged 12 to 15 years old in Beijing, China. This study is the first epidemiological survey on the prevalence of MIH in the pediatric population in North China. Some demographic and sociological factors were associated with the presence of MIH.