Background: The aim of this school-based, cross-sectional survey was to investigate the prevalence and risk factors of permanent Molar Incisor Hypomineralization among 7-9 years old school children in Muradnagar.
Methods: This cross-sectional study was performed among 7-9 years old school children in Muradnagar. Estimated sample size was 992 in this study. Multistage cluster sampling technique was used in this study in which schools were the clusters which were selected randomly. The study proforma was divided into 2 parts, first part comprised of demographic status, socio-economic status, questionnaires on risk factors of Molar Incisor Hypomineralisation such as prenatal, perinatal and postnal history upto 3 years, feeding pattern, fluoride and other pollutants exposure history, dental history, history of trauma to teeth/face, family history of enamel defects which was asked to the mothers and filled by one examiner in a face to face interview. The second part comprised of recording format of clinical variables assessed by investigator to be recorded by the recording clerk. Molar incisor hypomineralisation were recorded using Modified Developmental Defect of Enamel index developed by Clarkson J.J. and O' Mullane D.M. in 1989 and dental caries by using Decayed Missing Filled Tooth index (World Health Organization Modification 1997) in which WHO probe was used for examination of dental caries as recommended by WHO in the Oral Health Surveys, Fourth edition; 1997 (Spanish version). Before 1997 modification dental explorer was used for the examination of dental caries. Chi square test, Pearson's Correlation test, Logistic Regression Analysis and Unpaired t-test were used for analysing the data.
Results: The overall prevalence rate of Molar incisor hypomineralisation was 21.4% in this study. Age, problems during pregnancy, normal delivery and childhood illness/ infections are the risk factors which have highest strength of association.
Conclusion: In the present study Molar incisor hypomineralisation was found to affect 2 out of every 10 children examined which was higher than that observed in other studies on Indian children.
Keywords: Demarcated opacity; Developmental enamel defects; Diffuse opacity; Enamel hypoplasia; Modified developmental defect of enamel index; Molar incisor hypomineralization; Risk factors; School children.