Root canal filling materials spread pattern mimicking root fractures in dental CBCT images

Objective. To clarify the cause of artificial tooth-root fracture lines in cone beam computed tomography (CBCT) images caused by root canal filling materials and to enhance the diagnostic performance of CBCT. Study Design. We analyzed the CBCT images of 18 extracted human teeth (9 upper central incisors and 9 lower premolars) that were filled with a size 50 gutta-percha cone and inserted into tooth sockets in a human skull. Results. The CBCT images of the incisors displayed artificial lines in the oblique directions, notably the mesiobuccal, distolingual, distobuccal and mesiolingual directions, but only rarely in the cross-directions (buccal, lingual, mesial, and distal). In the premolars, the reverse was true, with lines mainly in the cross-directions, mesial and distal directions particularly. The lines were predominantly at the cervical slice. Conclusions. Artifacts resulting from root filling material appear along the long axis of the alveolar bones, and resemble root fractures.