Three canals in the mesiobuccal root of a maxillary first molar: a case report.

This article describes the identification and treatment of a maxillary first molar exhibiting three canals in the mesiobuccal root. An 18-yr-old male patient presented for nonsurgical root canal therapy of tooth #3. After accessing the pulp chamber, and probing with 2.5x magnification, only one canal was located in the mesiobuccal root initially. Subsequent to troughing the groove between the mesiobuccal and palatal canals with a #2 round bur, two additional canals were located. An electronic apex locator was utilized to ensure a perforation of the pulpal floor had not occurred. A working film confirmed the presence of three canals in the mesiobuccal root, and the canals were cleaned, shaped, and obturated.