Detection of a second mesiobuccal canal in maxillary molars by swept-source optical coherence tomography

The purpose of this study was to investigate the ability of swept-source optical coherence tomographic (SS-OCT) imaging to detect a second mesiobuccal canal (MB2) in maxillary molars compared with visual inspection (VI) and dental operating microscopy (DOM).

Forty extracted human maxillary molars were examined. After the removal of half the crown and access cavity preparation, the existence of MB2 canals was confirmed based on cross-sectional images of each tooth obtained by micro-computed tomographic scanning as the reference standard. Then, the pulp chamber floor was scanned by SS-OCT imaging. Three dentists independently evaluated the SS-OCT images and the pulp chamber floor under VI and DOM for the presence of MB2 canals. The detection rate of MB2 canals for SS-OCT imaging, VI, and DOM was calculated, and statistical analysis was performed.

MB2 canals existed in 19 of 40 teeth (47.5%) using micro-CT imaging. Sensitivity of DOM (0.947) was significantly higher than that of SS-OCT imaging (0.632). Specificity of SS-OCT imaging (0.714) was significantly higher than that of DOM (0.333). No statistically significant differences were found for accuracy among the 3 methods. Kappa values of SS-OCT, VI, and DOM were 0.526, 0.417, and 0.326, respectively.

SS-OCT imaging is noninvasive, involves no ionizing radiation, and is accurate for the detection of MB2 canals.