Objective: To investigate risk factors involved in the development of molar incisor hypomineralization (MIH) in a group of school-aged Iraqi children.
Methods: 823 seven-to-nine year-old schoolchildren had their first permanent molars and incisors evaluated using the European Academy of Paediatric Dentistry evaluation criteria for MIH. Mothers of the children completed a medical history questionnaire-based interview in the schools by a trained examiner.
Results: A response rate of 82.3% was obtained. For children with MIH, 6% reported no relevant medical history; the remaining 94% reported various medical conditions putatively associated with MIH compared with 70% for the non-MIH-affected group. Postnatal medical conditions (27%) were the most frequently reported followed by perinatal and prenatal conditions (5% and 4.5%, respectively). Of the MIH cases, 57.5% had medical conditions in more than one chronological period, mainly during the combined peri- and postnatal period (19.5%). When data were split into the possible risk-effect groups, maternal psychological distress (OR 4.45), frequent exposure to ultrasonic scans during the last gestational trimester (OR 3.17), soy-extract intake in the second year of childhood (OR 2.58) and birth-order (OR 7.28) were previously unreported significant risk factors and postulated as contributing to, or causing MIH.
Conclusions: Children with MIH had experienced a greater number of medical conditions than their unaffected peers particularly during the postnatal period with no single factor identified as a predisposing cause of the defect.