title: Differential diagnosis of vertical root fractures using reconstructed three-dimensional models of bone defects.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the accuracy of diagnosing vertical root fractures (VRFs) by comparing the volume of bone defects in VRFs with those in non-VRFs on reconstructed three-dimensional (3D) models (TDMs) using CBCT.
  
  
  METHODS
  32 maxillary pre-molars and anterior teeth with radiolucent areas were evaluated on pre-operative CBCT images. Of the 32 teeth, 16 had a fractured root (VRF group) and 16 had a non-fractured root (non-VRF group). The radiolucent area of each tooth was traced in each dimension [mesiodistal, buccolingual and horizontal (the apicoincisal aspect)] by two observers, and 3D images were reconstructed with the Amira(®) software (Visage Imaging Inc., Richmond, Australia). The volume, V, of the TDM was divided into the coronal side and the periapical side at the horizontal slice through the apical foramen, and v was defined as the volume of the coronal side. The values of v/V were calculated for all cases. The Mann-Whitney U test was used to compare values between the VRF group and the non-VRF group (p < 0.05). A receiver operating characteristic (ROC) curve was constructed to select the optimal cut-point.
  
  
  RESULTS
  There was a statistically significant difference in the value of v/V between the two groups (p < 0.05). With a cut-point derived from the ROC curve, and the sensitivity, specificity and accuracy of predicting the VRFs were 1.00, 0.75 and 0.88, respectively.
  
  
  CONCLUSIONS
  Lesions resulting from VRFs can be distinguished from those of non-VRFs on 3D CBCT images with a high degree of accuracy, based on their different 3D shapes.
authors.affiliation: Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Medical and Dental Sciences Track, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Komatsu
authors.forename: Y
authors.initials: Y
authors.lastname: Abe
authors.forename: T
authors.initials: T
authors.lastname: Yoshioka
authors.forename: H
authors.initials: H
authors.lastname: Ishimura
authors.forename: A
authors.initials: A
authors.lastname: Ebihara
authors.forename: H
authors.initials: H
authors.lastname: Suda
keywords: cone beam computed tomography; periapical periodontitis; three-dimensional imaging; tooth fracture