Molar Incisor Hypomineralization and Its Prevalence

Molar incisor hypomineralization (MIH) is the hypomineralization of systemic origin of one to four permanent first molars, frequently associated with affected incisors. It is presented as demarcated enamel opacities of different colors, occasionally undergoing posteruptive breakdown. The characteristic feature of MIH is the clear demarcation between the affected and sound enamel. There is asymmetry of defects present in the molars and incisors where one molar or incisor can be severely affected, while the contralateral tooth may be clinically sound or have only minor defects.

The aim of this study is to evaluate schoolchildren of 7-12 years of age with at least one of the first permanent molars fully or partially erupted from randomly selected government and private schools in Chennai using the European Academy of Pediatric Dentistry (EAPD) criteria for MIH, to determine the prevalence and characteristics of MIH.

The dental examinations were performed in the classroom using a mouth mirror and explorer under a headlight. Teeth were wiped with gauze when necessary to remove plaque or the food accumulations. Surfaces that were examined were the buccal, lingual, palatal, and occlusal surfaces of permanent first molars and labial surfaces of upper and lower incisors. A single examiner was involved to avoid interexaminer bias. All the data were collected and scored using the EAPD criteria for MIH.

A total of 22 (12.9%) children out of the examined 170 had MIH.

Distribution of MIH was more in males, more in 9 years of age. A total of 13 children had first molars affected and 9 children had both incisors and molars affected. Molars were affected more than the incisors. Mandible was affected more in comparison with the maxilla. Right side was affected more than the left side. The distribution of MIH was more in government schools compared to private schools.