Patient presented with a non-vital pulp and symptomatic apical periodontitis. The preoperative radiograph displays an atypical root and canal configuration. The CBCT sagittal view shows that the mesiolingal and distal canals join and the mesiobuccal canal exits the root short of the root apex.
After access opening, three canals were located and instrumented. The postoperative radiograph confirms that the mesiobuccal and distal canals join and that there is an anastomosis between the mesial canals.