A comparison of cone-beam computed tomography with periapical radiography in the detection of separated instruments retained in the apical third of root canal-filled teeth

Introduction This study compared the diagnostic efficacies of cone-beam computed tomographic (CBCT) imaging and periapical radiography (PR) in the detection of retained separated instruments located at the apical third of filled root canals. Methods Sixty single-rooted extracted human teeth were instrumented to size #25 and were randomly divided to a simulated 2-mm #30 K-file (stainless steel or nickel-titanium) segment separation at the apical third of the canal (n = 40) or a control group without a separated instrument (n = 20). The canals were obturated to the separated instrument or the working length for the teeth without an instrument using gutta-percha with AH26 (Dentsply DeTrey GmbH, Konstanz, Germany) or Roth sealer (Roth International Ltd, Chicago, IL). The teeth were invested in a mandible model simulating the bone density and imaged using CBCT imaging and PR. The images were evaluated separately by 2 calibrated observers twice with an interval of 4 weeks. Cohen kappa was used to evaluate the observer agreement. Receiver operating characteristic curve analysis was used to evaluate the discrimination ability. Results The intraobserver kappa was 0.744 and 0.627, and between the observers, it was 0.593 and 0.275 for PR and CBCT imaging, respectively. Using PR, the mean sensitivity was 71.25%, and the specificity was 93.75%. Using CBCT imaging, the sensitivity and specificity were 41.25% and 71.25%, respectively. Although for PR the area under the curve values ranged between 0.75 and 0.91 (P <.05), for CBCT they ranged between 0.48 and 0.60 (P >.05), regardless of the instrument or the sealer type. Conclusions PR performed better than CBCT imaging for the detection of retained separated instruments located at the apical third of extracted human root canal-filled teeth.