A comparative analysis of periapical radiography and cone-beam computerized tomography for the evaluation of endodontic obturation length.

The aim of this study was to determine the consistency and inconsistency between the periapical radiography (PR) and cone-beam computerized tomography (CBCT) in evaluating the length of root canal obturations (RCOs) in vivo.Thirty-six maxillary and mandibular first and second molars yielding 109 obturated root canals with available PR and CBCT images were analyzed. The inclusion criterion was that the RCO extended 0-2 mm short of the radiographic apex on PR images. Teeth having root canal calcification, apical resorption, or poor quality PR/CBCT images were excluded. Agreement and disagreement between the 2 imaging modalities for obturation length were analyzed using the χ(2) test.A total of 30.3% of the RCOs evaluated by PR as having adequate length were diagnosed by CBCT to have inadequate length. Among these, 13.8% were overextended and 16.5% underextended as diagnosed by CBCT. When the distance from the filling tip to the radiographic apex was 0.5 to 1 mm on the PR image, the discordance rate was the lowest (11.1%) in all evaluated distance groups, significantly lower than with distances of 0-0.5 mm and 1.5-2 mm (P < .01). When RCOs were diagnosed as terminating at the facial/lingual side, overextension was the main evaluation result by CBCT in the disagreement evaluation with PR and significantly more frequent than those at the mesial/distal/central side (P < .01).CBCT evaluated 30.3% of the RCOs with radiographically adequate length as inadequate. When the RCOs radiographically terminated 0.5-1 mm short of the apex, the evaluation rated adequate for obturation length was comparatively reliable.