This article describes the diagnosis and treatment of bilaterally maxillary first molars with two canals in their distobuccal roots. A 13-year-old male came to the clinic with a severe pain of tooth #14. In the first session, after access and finding the main canals and the second mesio-buccal (MB2) canal, another canal was noticed in the distobuccal root. All teeth were examined and a severe decay was observed in the left maxillary first molar. After preparing the access cavity, another orifice was found between the palatal and distobuccal canals. The presence of the second distobuccal canal was confirmed using an apex locator and radiography.
Keywords: Anatomic Variation; Maxillary First Molar; Root Canal System; Second Distobuccal Canal