RESUMEN
The aim of this study was to investigate the prevalence of molar incisor hypomineralization [MIH] and its relationship with systemic conditions in a group of Iranian children. The study population comprised of 433 7-9 year olds, from four schools in Zahedan, Iran. Subjects were evaluated clinically by one examiner, and at a separate session, their mothers completed a coded medical history questionnaire. Hypo-mineralized molars and incisors were recorded based on DDE [developmental defects of enamel] index and DMFT [number of decayed, filled and missing teeth] was determined. Statistical analyses were performed using Chi-square and independent sample t-tests. Fifty-five [12.7%] children showed MIH. The overall mean number of affected teeth was 0.2. The mean value of DMFT in MH children was greater than in normal children. Demarcated opacities were the most frequent [76%] enamel defect. Mother's and child's medical problems during prenatal, perinatal and post natal period were significantly remarkable in MIH children. The prevalence of MIH in a group of Iranian children was 12.7%. Prenatal, perinatal and post natal medical conditions were more prevalent in children affected by MIH