Abstract: Objective： To evaluate the accuracy of cone beam computed tomography (CBCT) in assessing furcation involvements of mandibular molars. Methods: In the study, 38 furcation involvements of 22 mandibular molars which would accept furcation surgery were included. Pre-surgical examination, CBCT and periapical radiograph were performed. Then, intra-surgical furcation assessments were compared with those data. Results: Intra-surgical findings confirmed 86.8% of the CBCT data, with a weighed kappa of 0.976. Of the four parameters tested of detailed root anatomy and furcation morphology, the vertical bone loss, the mesial-distal bone loss and the length of the root trunk revealed by CBCT were consistent with their respective intra-surgical values (P>0.05): about vertical bone loss, CBCT was (4.03±2.27) mm, but in surgery was (4.32±2.31) mm; about mesial-distal bone loss, CBCT was (2.05±0.89) mm, but in surgery was (2.07±0.97) mm; about length of the root trunk, CBCT was (2.35±0.88) mm, but in surgery was (2.24±0.75) mm. The horizontal bone loss revealed by CBCT ［(3.40±1.27) mm］ was significantly smaller than that by surgery ［(3.72±1.19) mm］. However, the mean difference was only 0.32 mm. Periapical radiograph could only obtain vertical bone loss ［(2.17±1.32) mm］ and mesial-distal bone loss ［(1.46±0.88) mm］, which was significantly different from that obtained in surgery. Conclusion: CBCT proved high accuracy in assessing the furcation involvement of mandibular molars.

Key words: Cone-beam computed tomography, Furcation defect, Molar