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

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 specifi c distances around the mandibular canal by comparing them to those obtained from multi-slice computed tomography (msct) images. materials and 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 coeffi cient (icc). results: there was a signifi cant 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. conclusion: the results of this study showed that there is signifi cant difference between measurements obtained by cbct and msct. however, the difference is not clinically signifi cant. key words: cone beam computed tomography linear measurements, multi-slice computed