RESUMO
The aim was to evaluate the effectiveness of clinical methods in identifying the presence of second mesiobuccal canal in maxillary first molars. The influence of age and experience with microscopy was also assessed. Sixty six teeth were selected and the mesiobuccal canal was confirmed in all of the samples by Cone-Beam Computed Tomography. After endodontic cavity access, teeth were evaluated through direct visual; dental loupe and operating microscope. None of the methods was successful in finding the mesiobuccal canal in all samples. Professionals <40, the magnification did not influence the location. Professionals >40, the magnification significantly influenced the location. In the direct vision, professionals >40 years located fewer canals than those <40 years of age with experience. In conclusion, these preliminary findings showed that when the microscope was used, the professionals with experience, regardless of age, found a higher number of canals. The use of the microscope was significant for professionals >40 years.