title: Periapical bone defects of root filled teeth with persistent lesions evaluated by cone-beam computed tomography.
abstract: OBJECTIVE
  To evaluate and categorize the bone defects of root filled teeth with persistent periapical lesions by cone-beam computed tomography (CBCT).
  
  
  METHODS
  Slice images of 532 teeth with persistent periapical lesions were obtained by CBCT in 427 patients and were examined by two endodontists. The periapical lesions were categorized into five types according to the characteristics of the bone defect based on CBCT images. The prevalence of each type was determined and analysed statistically at a 5% significance level using logistic regression.
  
  
  RESULTS
  Of the 532 teeth analysed, 67% had buccal or labial bone plate defects (type II), 4% palatal or lingual bone plate defects (type III), 7%'through and through' defects (type IV) and 10% apical root protrusions from the bone plate (type V). Mandibular teeth had a significantly greater prevalence of type I lesions (P=0.0005) and a significantly lower prevalence for types IV (P=0.041), V (P=0.001), V-1 (P=0.015) and V-2 (P<0.001) as compared to maxillary teeth.
  
  
  CONCLUSIONS
  CBCT accurately identified the type of periapical bone defect in persistent lesions. Because 10% of the teeth had apical root protrusions, which could not be identified by periapical radiography, the diagnostic information obtained by CBCT was an essential component of the treatment planning process.
authors.affiliation: Pulp Biology and Endodontics, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yoshioka
authors.forename: I
authors.initials: I
authors.lastname: Kikuchi
authors.forename: C G
authors.initials: CG
authors.lastname: Adorno
authors.forename: H
authors.initials: H
authors.lastname: Suda
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000473:pathology; D000539:Alveolar Process / Q000000981:diagnostic imaging* / Q000473:pathology; D054893:Cone-Beam Computed Tomography; D006801:Humans; D008334:Mandible; D008437:Maxilla; D010483:Periapical Diseases / Q000145:classification / Q000000981:diagnostic imaging* / Q000473:pathology; D019252:Radiography, Dental, Digital / Q000295:instrumentation; D019227:Tooth Apex / Q000000981:diagnostic imaging* / Q000473:pathology; D014092:Tooth Root / Q000000981:diagnostic imaging / Q000473:pathology; D019553:Tooth, Nonvital / Q000000981:diagnostic imaging* / Q000473:pathology