IntroductionThe purpose of this study was to evaluate the diagnostic accuracy of cone-beam computed tomographic (CBCT) imaging in the detection of subtle vertical root fractures (VRFs) in endodontically treated teeth in vivo and to discuss direct and indirect evidence for the diagnosis of subtle VRFs. MethodsTwenty-nine endodontically treated teeth with suspected VRFs from 29 patients were examined using CBCT imaging. CBCT images were scored based on evaluation of the fracture line and vertical buccopalatal (lingual) bone loss. VRF was diagnosed only when a definite fracture line was detected on CBCT images, and findings of periodontal exploration or surgical extraction were considered the gold standard. The diagnostic sensitivity, specificity, and accuracy were assessed. ResultsOf the 29 teeth, 27 were positive and 2 were negative for VRF according to the gold standard. Sensitivity, specificity, and accuracy were 33.3%, 100%, and 37.9%, respectively, based on the direct finding of a fracture line on CBCT images. However, vertical buccopalatal (lingual) bone loss was found in 25 of 27 teeth with VRFs. ConclusionsAlthough the accuracy of CBCT imaging for the diagnosis of subtle VRFs in endodontically treated teeth in vivo was poor, vertical buccopalatal (lingual) bone loss is an important indirect sign for the diagnosis of VRFs, which can be found on CBCT images.