To assess the diagnostic accuracy of cone beam computed tomography (CBCT) in comparison with conventional radiography for vertical root fractures, 50 of 100 teeth were subjected to vertical root fracture (VRF) and then placed in dry mandibles. 3D scans were obtained for all teeth, and conventional radiographs were used as control images. All the images were assessed by 6 observers, who determined the presence of root fractures by using a 5-point confidence rating scale. The mean area under the curve (Az) for CBCT was 0.91, and that for conventional radiography was 0.64. The difference between the modalities was statistically significant (P = 0.003). On the basis of interclass coefficient, inter-observer agreement for CBCT was 0/750, and that for conventional radiography was 0/637. Thus CBCT was shown to be significantly better than conventional periapical radiography for diagnosis of vertical root fractures in vitro.

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Introduction. The purpose of this study was to investigate the relationship of the volume of lateral incisor resorption and impacted canine features. Materials and Methods. This study consisted of CBCT images of 47 samples with unilateral impacted maxillary canine (13 males and 34 females). The volume of lateral incisors in impacted side and nonimpacted side was calculated with the Mimics 10.01 software. Canine and lateral incisor angulations were measured in panoramic reformatted images. The canine cusp tip distance from midpalatal suture was measured in axial cross-section images. Results. The difference between two sides volume was considered as the mean volume of resorption (MVR) that was statistically significant ( P < 0.001 ). MVR was not statistically significant between two sexes ( P = 0.95 ), in buccopalatal and mesiodistal positions of impacted canine, and in different angulations or distances of the impacted canine to midline ( P > 0.05 ). The concurrent effect of the canine distance to the midline and the angle of the canine with the lateral incisor on the MVR were statistically significant ( P = 0.049 ). Conclusion. The maximum rate of lateral root resorption is when the distance from the canine to the midline is less than 5 mm and the angle of the canine to the lateral incisor is 30–60 degrees.

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Background: Determining the incidence and anatomic features of accessory mental foramen (AMF) in the Iranian population is of vital importance. This study investigated the prevalence and anatomic characteristics of AMF using cone-beam computed tomography (CBCT) in a selected Iranian population. Methods: A total of 853 CBCT images from 440 women and 413 men were examined in this cross-sectional retrospective study. The images were evaluated by two independent observers using reconstructed 3-dimensional, cross-sectional, and panoramic views. Several parameters were assessed, including the location of AMF relative to mental foramen (MF), size and the point of canal bifurcations, and the distance between the main and accessory canals. Finally, statistical differences in the AMF prevalence in terms of gender and direction and its location were evaluated by the Mann-Whitney U test (P<0.05). Results: The prevalence of AMF was 10.55%, which was more frequently located in the posterior inferior area relative to the main MF, and its nerve was more frequently originated from the anterior loop (P=0.001). There were no statistically significant differences in gender (P=0.26) and direction (P=0.4). The mean distance of AMF was 7.62 mm. The mean height of MF and the AMF vertical height were 13.65 mm and 52.12 mm in those with AMF on one side, respectively, and this difference was statistically significant (P=0.001). The sizes of the MF and AMF were 3.2 mm (large diameter), 2.3 mm (small diameter), and 1.4 mm (large diameter), and 1.1 mm (small diameter), respectively. Conclusions: Based on the findings of the present study, the prevalence of AMF according to hemi-mandibular was 5.80% in the selected Iranian population. Thus, AMF might branch from any section of the inferior alveolar nerve and the mandibular canal.