Molar-incisor hypomineralisation: a prevalence study amongst primary schoolchildren of Shiraz, Iran.

AIM: To investigate the prevalence of molar-incisor hypomineralisation (MIH) amongst primary schoolchildren of Shiraz, Iran, taking into account the possible influence of biographic and socio-demographic parameters. STUDY DESIGN AND METHODS: A randomised cluster sample of 9- to 11-year-old children (N = 810) had their first permanent molars and incisors (index teeth) evaluated using the European Academy of Paediatric Dentistry criteria for MIH. The examinations were conducted at schools by a calibrated examiner. Prevalence of MIH was assessed based on biographic and socio-demographic parameters including area of residency, school type, father's level of education, weight-for-age and height-for-age. RESULTS AND STATISTICS: Of the children examined, 164/810 (20.2%) had MIH and 53.7% of them presented with MIH lesions in all first molars. Mild defects represented by demarcated yellow brown opacities comprised 35.5% of the total MIH lesions. The prevalence of MIH was significantly greater in girls, children with healthy body weight and height, those whose fathers did not have a tertiary education and from families of low socio-economic status. Regression analyses indicated that none of the biographic and socio-demographic variables represented a significant risk factor in the occurrence of MIH except for body weight. Obesity was negatively correlated to MIH (OR = 0.45; 95% CI 0.25-0.82). CONCLUSIONS: The prevalence of MIH in a group of Iranian children was 20.2%. Biographic and socio-demographic parameters appeared to have no significant correlation with MIH except body weight, which warrants further research.