RESUMO
Objective: To evaluate systemic factors those are related to molar incisor hypomineralization (MIH), its association with dental caries, and the impact on oral health-related quality of life (OHRQoL) in Brazilian children. Material and Methods: This case-control study was conducted at the Pediatric Dentistry Clinic, Federal University of Parana, Brazil. Patients with MIH who were assisted from 2014 to 2015 were included in the study, for a total of 31 children, 6-13 years of age. The control group consisted of 62 children who were matched by sex and age. European Academy of Pediatric Dentistry criteria were used for MIH diagnosis. The children's mothers answered a questionnaire regarding the children's history of health intercurrences in the pre-, peri-, and postnatal periods. The Decayed, Missing, or Filled Teeth indices for permanent and primary teeth (dmft index and DMFT index, respectively) were used for dental caries examination by two calibrated examiners. Child Perceptions Questionnaires for 8- to 10-year-old children and 11- to 14-year-old children (CPQ8-10 and CPQ11-14) were used to assess OHRQoL. Results: Prematurity and prolonged delivery were significantly associated with the occurrence of MIH. In the postnatal period, recurrent fevers in the first 3 years of life were associated with MIH. Of the 339 incisors and first permanent molars that were examined, 178 presented MIH, of which 116 (65%) were demarcated opacities. A significant difference was found in the mean DMFT index between groups. No impact of MIH on OHRQoL was observed. Conclusion: The present results suggest higher intercurrences during the perinatal period and a higher incidence of caries among children with MIH.