BackgroundMolar-incisor hypomineralisation (MIH) is the most common developmental abnormality observed in teeth. Being a relatively new condition, its treatment can present a challenge for the dentist. There is currently no study available that has evaluated the knowledge of Mexican dental personnel. This study aimed to evaluate the knowledge, experience, and perceptions of dental surgeons regarding the detection, assessment, and treatment of MIH in the metropolitan area of Mexico City.MethodsA cross-sectional study was designed. Dentists from Mexico City and its metropolitan area were invited through social networks to answer a questionnaire of 30 questions related to MIH. Participants were classified into general practice dentists, paediatric dentists, and other speciality dentists. Pearson’s chi-square test was used for data analysis.ResultsThe questionnaire was answered by 391 dentists. A total of 86% (338 out of 391) of them identified MIH lesions, while 84% of them reported having observed MIH lesions in their practice. The most frequently observed lesions were yellow-brown opacities which accounted for 47% of the lesions, 46% were white opacities, while only 7% were observed as post-eruptive fractures in the enamel as part of the manifestations of MIH. The most frequently reported problem in the management of teeth with MIH was insufficient training for treating children with MIH. A total of 84% of dentists stated that they would like more information on the treatment of MIH lesions.ConclusionsMost of the surveyed dentists recognised MIH and reported having observed MIH lesions in their practice. Most of the dentists indicated that the main problem for the management of the MIH is the lack of training.