title: A comparative analysis of periapical radiography and cone-beam computerized tomography for the evaluation of endodontic obturation length.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: State Key Laboratory of Oral Disease, West China College of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Li
authors.initials: L
authors.lastname: Cheng
authors.forename: Ru
authors.initials: R
authors.lastname: Zhang
authors.forename: Xuan
authors.initials: X
authors.lastname: Yu
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Tian
authors.forename: Hu
authors.initials: H
authors.lastname: Wang
authors.forename: Guangning
authors.initials: G
authors.lastname: Zheng
authors.forename: Tao
authors.initials: T
authors.lastname: Hu
mesh_terms: D000293:Adolescent; D000328:Adult; D016009:Chi-Square Distribution; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003786:Dental Pulp Cavity / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible; D008437:Maxilla; D008875:Middle Aged; D008963:Molar / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D010486:Periapical Tissue / Q000000981:diagnostic imaging*; D011861:Radiography, Dental / Q000379:methods; D015203:Reproducibility of Results; D012389:Root Canal Obturation / Q000379:methods / Q000592:standards*; D019227:Tooth Apex / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D055815:Young Adult