title: A comparative study of accuracy of linear measurements using cone beam and multi-slice computed tomographies for evaluation of mandibular canal location in dry mandibles.
abstract: BACKGROUND
  Cross- sectional tomograms have been used for optimal pre-operative planning of dental implant placement. The aim of the present study was to assess the accuracy of Cone Beam Computed Tomography (CBCT) measurements of specific distances around the mandibular canal by comparing them to those obtained from Multi-Slice Computed Tomography (MSCT) images.
  
  
  METHODS
  Ten hemi-mandible specimens were examined using CBCT and MSCT. Before imaging, wires were placed at 7 locations between the anterior margin of the third molar and the anterior margin of the second premolar as reference points. Following distances were measured by two observers on each cross-sectional CBCT and MSCT image: Mandibular Width (W), Length (L), Upper Distance (UD), Lower Distance (LD), Buccal Distance (BD), and Lingual Distance (LID). The obtained data were evaluated using SPSS software, applying paired t-test and intra-class correlation coefficient (ICC).
  
  
  RESULTS
  There was a significant difference between the values obtained by MSCT and CBCT measurement for all areas such as H, W, UD, LD, BD, and LID, (P < 0.001), with a difference less than 1 mm. The ICC for all distances by both techniques, measured by a single observer with a one week interval and between 2 observers was 99% and 98%, respectively. Comparing the obtained data of both techniques indicates that the difference between two techniques is 2.17% relative to MSCT.
  
  
  CONCLUSIONS
  The results of this study showed that there is significant difference between measurements obtained by CBCT and MSCT. However, the difference is not clinically significant.
authors.affiliation: Torabinejad Dental Research Center, Department of Oromaxillofacial Radiology, School of dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Asieh Zamani
authors.initials: AZ
authors.lastname: Naser
authors.forename: Bahar Behdad
authors.initials: BB
authors.lastname: Mehr
keywords: Cone beam computed tomography linear measurements; multi-slice computed tomography