Résumé
Background: The success of endodontic therapy depends on the complete debridement of the entire root canal system. Manystudies have investigated the morphology of mandibular molar, but the prevalence of the middle mesial canal in the mesialroot of the mandibular first molar is still the subject of controversy. Missed canal and consequently inadequate debridement ofthe root canal system can eventually lead to failure of therapy. Hence, it is imperative to meticulously look for extra canals toensure successful treatment.Materials and Methods: In this in vivo study, 100 patients who reported for root canal treatment were included in the study.Patients’ age and sex were recorded. After access cavity preparation, a standardized technique is performed between themesiobuccal canal and mesiolingual canal to search for a middle mesial canal using a dental operating microscope and confirmedradiologically by taking cone-beam computed tomographic image and results were analyzed.Results: In our study, out of 100 patients included that 50 patients were male and 50 patients were female. Based on gender,the prevalence of middle mesial canal in tooth number 36 and 46 is 18% (9 patients) and 19% (10 patients); for females andmales, it is 20% (10 patients) and 22% (11 patients). Based on age group, the prevalence of middle mesial canal in tooth number36 and 46 between the age of 15 and 30 is 23% (13 patients) and 24% (15 patients), between the age of 31 and 60 is 20%(5 patients) and 22% (6 patients), and age above 60 is 14% (1 patient) and 16% (2 patients), respectively.Conclusion: From this study, we concluded that the prevalence of the middle mesial canal in the permanent mandibular firstmolar can be as high as 24%, with the prevalence being higher in males than females and the age group between 15 and30 years had the highest prevalence.