Tooth Demineralization, Orthodontics, Knowledge.

Introduction: Molar Incisor Hypomineralization (MIH) is a qualitative defect of dental enamel, which makes it fragile and porous, and can interfere with orthodontic practice. Thus, it is necessary for the orthodontist to know this enamel change. Aim: To assess the level of knowledge and clinical practices of orthodontists in relation to MIH. Methodology: We performed a cross-sectional observational study among brazilian orthodontists to evaluate their practices and previous knowledge regarding MIH. We developed a questionnaire including questions about MIH diagnosis, clinical experience and orthodontic approaches regarding MIH. The questionnaire was validated by pediatric dentists (using the Delphi method) and sent to orthodontists acting in all brazilian regions. Orthodontists who did not reside in Brazil and those who were temporarily unable to practice the speciality were excluded from this study. At total, responses from 351 orthodontists were considered. Results: Although 80.1% orthodontists claimed to know the HMI, 44.2% said they did not feel confident in carrying out their diagnosis. There was no significant association between the level of knowledge of these professionals and the sociodemographic variables (p>0.05), with the exception of the gender variable, where females showed satisfactory knowledge regarding MIH, when compared to males (p<0. 05). The HMI has been noticed by 74.4% of the participants in their clinical routine, and 80.3% stated that these changes directly affect their orthodontic practices. Conclusion: Although orthodontists know the MIH, they do not fully master its characteristics and peculiarities. There are no ideal protocols in the literature for the conduct of bonding, cementing and debonding of orthodontic accessories in teeth with MIH, which highlights the need for further studies in this regard. In this way, the orthodontist will be able to help in the preservation of teeth with MIH, avoiding possible iatrogenesis during the orthodontic treatment and conducting the case in the best possible way.