Influence of voxel size on the diagnostic ability of cone-beam computed tomography to evaluate simulated root perforations

This study aimed to assess the use of different voxel sizes of a cone-beam computed tomography (CBCT) unit for detecting root perforations of different sizes and locations ex vivo and to compare the diagnostic possibilities of CBCT with those of periapical radiography (PR). The study included 36 recently extracted intact human mandibular one-rooted teeth with developed apices. Root perforations of 0.2, 0.3, or 0.4 mm in diameter were drilled on the buccal and lingual sides at the cervical, middle, and apical thirds. A total of 216 portions were obtained. One tooth at a time was placed in a dry human mandible in an artificially created alveolus. Cross-sectional CBCT images were obtained using voxel resolutions of 0.4, 0.3, 0.25, and 0.2 mm. PRs were obtained using the paralleling technique in three directions in the horizontal plane: direct view, mesial angulation, and distal angulation with a 20A degrees angle. There were no significant differences in sensitivity between 0.4/0.3 and 0.25/0.2-mm voxel resolutions. Significant differences were found between voxel sizes of 0.4/0.25, 0.4/0.2, 0.3/0.25, and 0.3/0.2 mm. The observers failed to diagnose any of the perforations using PR. CBCT is a reliable imaging system for detecting root perforations that are not detectable with PR. A 0.2-mm voxel resolution was the best choice for diagnostic use in this study. Neither perforation location nor size influenced the diagnostic abilities of CBCT, except that it was harder to detect a root perforation in the apical part of the root.