RESUMEN
OBJECTIVE: To assess whether the prevalence of dental caries is associated with the presence of molar-incisor hypomineralisation (MIH) in first permanent molars (FPMs). METHODS: A cross-sectional study was conducted with a sample of 5368 FPMs from 1342 children aged 8-10 years from Florianopolis, Brazil. Dental caries was evaluated with the Decayed, Missing and Filled Teeth (DMFT) index and MIH was assessed according to the European Academy of Paediatric Dentistry (EAPD) criteria. The sociodemographic data were obtained with a questionnaire sent to caregivers. A hierarchical repeated measures Poisson regression, considering dependency among observations, was performed, since the unit of analysis was the tooth. RESULTS: The presence of MIH was associated with a 6.15 times higher prevalence of dental caries in FPMs (PR: 6.15; 95%CI: 4.18-9.04). A monthly family income ≤2 minimum wages and the caries experience in the primary teeth were also significantly associated with greater prevalence rates of dental caries in FPMs. CONCLUSION: The presence of MIH showed a significant association with the prevalence of dental caries in FPMs. Thus, dentists should be alert to cases of MIH. Once the condition is detected, preventive measures should be taken to prevent enamel breakdown and the development of dental caries lesions.