An ex vivo comparison of digital radiography and cone-beam and micro computed tomography in the detection of the number of canals in the mesiobuccal roots of maxillary molars.

INTRODUCTION: The purpose of this study was to compare digital periapical and cone-beam computed tomography (CBCT) images to determine the number of canals in the mesiobuccal root of maxillary molars and to compare these counts with micro computed tomography (muCT), which was also used to determine canal configuration. METHODS: Digital periapical (RVG 6100), CBCT (9000 3D), and muCT images (the reference standard) were obtained of 18 hemi-maxillas. With periapical and CBCT images, 2 endodontists independently counted the number of canals in each molar and repeated the counts 2 weeks later. Teeth were extracted and scanned with muCT, and 2 additional endodontists, by consensus, determined the number and configuration of canals. The Friedman test was used to test for differences. RESULTS: In mesiobuccal roots, 2 canals were present in 100% of maxillary first molars (13 of 13) and 57% of second molars (8 of 14), and 69% (9 of 13) and 100% (8 of 8) of these exited as 2 or more foramina. There was no difference in canal counts for original and repeat reads by the 2 observers with periapical (P = .06) and with CBCT (P = .88) and no difference when CBCT counts were compared with muCT counts (P = .52); however, when periapical counts were compared with muCT counts, there was a significant difference (P = .04). CONCLUSIONS: For cadaver maxillary molars, muCT canal counts were significantly different from digital periapical radiograph counts but not different from Carestream9000 3D CBCT counts.