BackgroundAlthough studies throughout the world have investigated potential factors involved in the occurrence of molar incisor hypomineralization (MIH), the findings are varied and inconclusive.ObjectiveThe aim of the present study was to evaluate the prevalence of MIH and identify associated prenatal, perinatal and postnatal factors among Brazilian schoolchildren aged 8 and 9 years.MethodsA cross-sectional study was conducted with a randomly selected population-based sample of 1181 schoolchildren. Information on demographic and socioeconomic characteristics as well as prenatal, perinatal and postnatal aspects was obtained through questionnaires. The clinical examination included the investigation of MIH based on the criteria of the European Academy of Paediatric Dentistry. Dental caries in the permanent dentition and developmental defects of enamel (DDE) on the primary second molars were also recorded. Data analysis involved descriptive statistics, bivariate tests and Poisson regression with robust variance.ResultsThe prevalence of MIH was 20.4%. MIH was more frequent among children with dental caries in the permanent dentition (PR: 2.67; 95% CI: 1.98–3.61), those with DDE on the primary second molars (PR: 2.54; 95% CI: 1.87–3.45) and those who experienced asthma/bronchitis in the first four years of life (PR: 1.93; 95% CI: 1.45–2.56).ConclusionsThe prevalence of MIH was high and was associated with dental caries, the presence of DDE on primary second molars and the experience of asthma/bronchitis in early life. These findings could be useful in the identification of children in need of shorter recall intervals to prevent the consequences of MIH, such as enamel breakdown dental caries.

This study sought to determine the prevalence of developmental defects of enamel (DDE) among preschool children and investigate associations with sociodemographic and socioeconomic factors and weight status. A cross-sectional study was conducted with 118 children aged 3 to 5 years. Data were collected via clinical examinations and a self-administered questionnaire completed by the parents. The diagnosis of DDE was performed using the modified DDE Index. Information on socioeconomic indicators (mother's schooling, monthly income per capita), child's sex and age, and age of mother at the birth of the child were obtained by questionnaire. The children's weight status was determined based on weight-for-age at the time of the exam. Statistical analysis involved the chi-squared test and Poisson regression with robust variance. The prevalence of DDE was 50.0%. DDE were more frequent in males (p = 0.025) and children whose families were classified as being at poverty line (p = 0.040). In the Poisson model controlled for child's sex and mother's schooling, children whose families were classified as being at the poverty line had a greater prevalence rate of DDE. In conclusion, the prevalence of DDE was high in the present sample and associated with lower household income. Weight status was not associated with DDE.

Background: Bruxism is characterized by tooth grinding and/or clenching. Aim: To evaluate the association between possible awake bruxism (PAB) and bullying among individuals aged 8-11 years. Design: A representative cross-sectional study was conducted with 434 eight-to eleven-year-old children/adolescents. Parents/caregivers answered a questionnaire to provide data on sociodemographic characteristics. Children/adolescents answered a questionnaire about the occurrence of PAB. The Olweus Bully/Victim Questionnaire was used. The Poisson regression analysis was performed. Results: Of the 434 children/adolescents, 209 (48.2%) were boys and 225 (51.8%) were girls. The mean age of the children/adolescents was 9.14 years (±1.00).Children/adolescents who were victims of bullying (PR = 1.52, 95% CI = 1.14-2.04, P = .005) and bullies-victims (PR = 2.08, 95% CI = 1.36-3.17, P = .001) presented a higher frequency of PAB than those who were not involved in bullying. Conclusion:Children/adolescents who were bullying victims and bullies-victims had a higher frequency of PAB.

Background Some oral conditions can have psychosocial consequences that affect children's daily life and well‐being. Aim To create a structural model for the determination of dental caries, molar–incisor hypomineralization (MIH), and the impact of these conditions and socioeconomic status on schoolchildren's oral health‐related quality of life (OHRQoL). Design A representative cross‐sectional study was conducted in Lavras, Brazil, with 1181 female and male schoolchildren 8–9 years of age. OHRQoL was measured using the Brazilian version of the CPQ8‐10. Clinical examinations were performed by a calibrated dentist for the diagnosis of dental caries (WHO) and MIH (EAPD). Parents/caregivers answered questionnaires addressing the child's medical history and socioeconomic status. Data were analyzed using structural equation modeling. Results The model revealed that greater MIH severity (β = .874; p < .001) and worse socioeconomic status (β = −.060; p = .001) were associated with a greater number of teeth with caries experience. The higher the number of teeth with caries experience (β = .160; p = .007) and worse socioeconomic status (β = −.164; p < .001), the greater the negative impact on OHRQoL. Conclusion The model created showed that dental caries and socioeconomic status had a direct negative impact on the OHRQoL of schoolchildren and MIH had an indirect impact mediated by the occurrence of caries experience.