A = Preoperative periapical radiograph of a left mandibular first molar.
B = Periapical radiograph showing the working length determination of six root canals.
C = Enlarged axial CBCT image section at the mid-root level showing 4 canals in the distal root and 2 canals in the mesial root.
D = Enlarged coronal section of the distal root showing the configuration of the four canals.
E = Enlarged sagital section of the distal root showing the overlapping of the four canals.
F = Postoperative periapical radiograph showing all root canals.
G = Six months follow-up of the root canal treatment.