Efficacy of Cone Beam Computed Tomography for Detecting Canal Lumina

Calcified canals pose diagnostic and treatment challenges. Conventional projection radiography is compromised by the presence of superposed complex local anatomy. Cone-beam computed tomography (CBCT), which offers cross-sectional imaging, has the potential to offer improved visualization of root canals. Objective: The purpose of this study was to evaluate the efficacy of CBCT for detecting root canal lumina in extracted human teeth compared to conventional imaging. Methods: Fifteen teeth appearing to have partially calcified canals by conventional radiography were selected for this study. These teeth were examined by microCT and scored for presence of any canal lumen. These scores served as the gold standard. Two imaging systems were compared for their ability to detect any evidence of a root canal lumen: CBCT images (3DX Accuitomo, J. Morita) and periapical F-speed film radiographs (PA). The test teeth were mounted in a dry sagittally-sectioned mandible and CBCT scans were made. Periapical radiographs were also made in straight on as well as with 20-degree mesial and distal shifts. The CBCT and PA radiographs were evaluated by three endodontists and scored for presence of any canal lumen in each root. The CBCT images were evaluated dynamically in the axial, sagittal and coronal planes. The observers were blinded to the results of the microCT analysis. Results: MicroCT revealed at least partial canal lumina in all roots. Root canal lumina were detected by our observers in an average of 98% of the roots using CBCT and 64% of roots using PA radiographs. The increase in the detection frequency was 34% with a standard deviation of 24% (p=0.14). The average agreement between observers was 98% for CBCT and 60% for PA radiographs. Conclusion: There is a clear trend for increased detection of root canal lumina and increased observer agreement using 3DX Accuitomo images compared to conventional periapical radiographs.