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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Introduction. Although primary teeth have a determinative role in development of normal occlusion, few studies about anomalies related to deciduous dentition have been conducted so far. Regarding recent improvements in common knowledge and the importance of maintaining primary teeth until eruption of succedaneous teeth, identifying the morphology of primary teeth and probable variations is of great importance to achieve optimal therapeutic outcome. This study aims to determine the prevalence of three-rooted mandibular primary molars in a population of northwestern Iran. Materials and Methods. In this descriptive cross-sectional study, periapical radiographs of patients attending private oral and maxillofacial radiology offices in the northwestern region of Iran from 2017 to 2019 were retrospectively reviewed. A total of 300 cases in the 3– 10 -year age range having bilateral periapical radiographs from mandibular primary molars were screened. First and second primary molars were observed meticulously. Gender, side of the mandible (right or left), symmetry, overall prevalence, and prevalence considering the type of molar (D or E) were recorded and analyzed. Results. Overall prevalence of three-rooted mandibular primary molars was 9.33 % (   28 / 300 ), 92.9 % of which were unilateral. The prevalence of teeth showing supernumerary roots among all teeth examined was 2.5 % ( 30 / 1200 ). Considering symmetry and gender, the occurrence of these three-rooted primary molars did not differ significantly (respectively, p = 0.832 and p = 0.541 ). However, there was a significant relationship between the occurrence of supernumerary roots and left side for three-rooted first molars and right side for three-rooted second molars ( p = 0.021 ). Conclusion. Obtained data show that three-rooted mandibular primary molars in children of northwest region of Iran have a prevalence of approximately 10   % which urges some specific considerations in exodontic and endodontic procedures.

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.

Objectives This study aimed at comparing the size and shape of mandibular condyle in mature adult population with different skeletalpatterns.Methods A total of 198 patients within the age range of 15–64 years, including 68 males and 130 females, were allocated into three groupsbased on the ANB angle: skeletal classes I (n = 65), II (n = 69), and III (n = 64). The cone beam computed tomography (CBCT) was used toevaluate right and left temporomandibular joint (TMJ) in each patient. TMJ evaluation was comprised of size of condyle, area of condyle,and morphology index. The Mimics software was used to calculate the size and area of the condyle. The size, area, and morphology indexwere compared between the study groups using parametric tests.Results Based on the results of paired t-test, there was a significant difference between the sizes of right and left condyles, in favor of theright condyle (P = 0.02). In addition, the mean size of the condyle in class III subjects was higher than those of classes I and II; however, thedifference between the classes I and II was insignificant. The size and area of condyle were higher in males compared with females.Conclusion Based on the results of this study, there might be a correlation between the facial skeletal morphology and area of condyle.