Sensitivity of conventional radiographs and cone-beam computed tomography in detecting the remaining root-canal filling material.

This study aimed to compare the sensitivity of radiographs and flat-panel volume-computed tomography (fpVCT) in detecting the remaining root-canal filling material. Thirty-two root canals in extracted human mandibular molars were prepared and obturated with gutta-percha and sealer. The filling material was removed, and the teeth were split longitudinally. Radiographs and fpVCT scans were obtained and digitized. Virtual images were developed using reconstruction software and then superimposed, and the remaining filling material was outlined. Direct observation of the split root halves using flatbed scans served as a control. The presence and extension of the remaining filling material were evaluated. Statistical analysis was conducted using chi-squared test (P < 0.05). A total of 116 remnants were detected in the flatbed scans, 81 in the fpVCT scans, and 90 in the radiographs, with no significant difference between the radiograph (78%) and fpVCT (70%) results (P = 0.18). In the fpVCT scans, 42% of the remnants exhibited the same dimensions as the control, whereas 27% appeared larger and 30% appeared smaller. In the radiographs, the dimensions of the remnants were identical to the control in 64% of cases, smaller in 29%, and larger in 7%. FpVCT did not exhibit better performance than dental radiographs in detecting the remaining root-canal-filling material: the extension of remnants was indicated correctly in the fpVCT in fewer than 50% of the samples.