The detection of vertical root fractures in post-core restored teeth with cone-beam CT: in vivo and ex vivo

Abstract

Objectives: To compare the accuracy of cone-beam CT ex vivo and in vivo for the detection of artificially created large and small vertical root fractures in extracted teeth restored with post-core. Methods: Individual metal cast post-cores were fixed in the root canals of 50 extracted single-rooted human teeth. In 30 teeth fractures were created by tapping posts with a hammer. The teeth were sterilised in autoclave and embedded into bite-plates made of silicon impression material. Cone-beam CT scanning was performed ex vivo and in vivo . For the in vivo scanning, teeth in sterile plastic bags were inserted into the mouths of volunteers. Then the teeth were sectioned with low-speed saw and the widths of the VRFs were measured microscopically. The teeth were distributed into 2 groups in accordance with the measured fractures’ widths: large (wider than 180–250 µm) and small (80–150 µm). Five observers assessed the presence of vertical root fractures on axial CBCT slices. Sensitivity, specificity, accuracy and inter examiner agreement were calculated. Results: The accuracy of cone-beam CT in vitro for large and small vertical root fractures detection was 0.56 and 0.40 respectively (p = 0.043). The sensitivity values were 0.53 and 0.27 for large and small vertical root fractures, respectively (p = 0.043). The visualisation of fracture lines in vivo was impossible in 90 % of cases, because of low image quality. Inter examiner reliability analysis showed κ values ranging from 0.02 to 0.54. Conclusions: Fracture width affected the in vitro detectability of vertical root fractures by cone-beam CT in teeth with metal cast post-cores. The detectability of root fractures in vivo was decreased because of low image quality, making the assessment of sound tooth tissue impossible.