Most failures in endodontic treatment of mandibular incisors are due to the presence of a missed canal specifically the lingual. This investigation aimed to examine the root morphology and number of canals in mandibular incisors using cone beam computed tomography (CBCT). Two hundred and seven patients were assessed in terms of their mandibular central and lateral incisors of CBCT. The inclusion criteria were absence of root resorption, coronal restoration or root filling and clarity and optimal resolution of images. According to the Vertucci's classification, number of roots and canals and type of canal were evaluated by two oral and maxillofacial radiologists. In order to data analysis SPSS version 16 and descriptive statistics were implemented. All mandibular incisors had one root. Most central (84.5%) and lateral (78.2%) incisors had a single canal (p= 0.065). The majority of central (54.5%) and lateral (56.5%) incisors were Vertucci's type I (p= 0.102). Prevalence of one canal in males: central (84.8%), lateral (77.9%) and in females: central (84.2%), lateral (78.5%) (p= 0.518). Prevalence of Vertucci's type I in males: central (52.3%), lateral (45.3%) and in females: central (56.1%), lateral (64.4%) (p=0.188). The prevalence of two canals was 15.5% (central) and 21.8% (lateral) in mandibular incisors. The Vertucci's type I was the most typical kinds of mandibular incisors. Considering the limitations of periapical radiography in determining canal morphology, CBCT can be helpful in case of any concern regarding root canal morphology.

To assess the prevalence of soft tissue calcifications and their panoramic radiographic characteristics. Material and Methods: This descriptive retrospective study evaluated 2027 panoramic radiographs. The type and location of calcifications and the age and gender of patients were evaluated by two radiologists. Data were analyzed via SPSS and the Chi-square, Fisher's exact and Kappa tests were used to compare the categorical demographic variables among the groups. The confidence interval was set to 95% and p<0.05 was considered statistically significant. Results: The prevalence of calcified stylohyoid ligament was 11.24%. This value was 3.99% for tonsillolith, 1.33% for calcified carotid plaque, 0.69% for antrolith, 0.39% for calcified lymph node, 0.29% for phleboliths, and 0.19% for sialoliths. The prevalence of these conditions had no significant association with gender or age (p=0.102). The prevalence of bilateral calcified stylohyoid ligament, tonsillolith, and a calcified carotid plaque was significantly higher (p<0.001). The most prevalent type of calcified stylohyoid ligament, according to O'Carroll's classification, belonged to types 1, 4, 3 and 2 (p<0.001). The most commonly observed radiographic pattern was multiple, well-defined tonsilloliths (75.3%, p<0.001). Conclusion: The prevalence of soft tissue calcifications on panoramic radiographs was relatively low in this Iranian population. The most calcifications were respectively calcified stylohyoid ligament, tonsillolith, calcified carotid plaque, antrolith, calcified lymph node, phleboliths and sialoliths. Calcified stylohyoid ligament, tonsillolith and calcified carotid plaque were more bilaterally. Thereby panoramic imaging can help in primary assessment, epidemiologic and screening evaluation of these calcifications.

Objective: This study aimed to assess the knowledge level of Iranian dental practitioners about digital radiography(DR) andcone-beamcomputedtomography (CBCT). Material and Methods: In this crosssectional study, a researcher-designed questionnaire was administered among 180 general dentists and specialists. The questionnaire had three main domains of demographic information, fifteen questions about knowledge of DR (advantages, disadvantages, physical properties) and twenty six questions about knowledge of CBCT (indications, applications, advantages, route of knowledge acquisition). Data were analyzed using descriptive statistics, t-test and Pearson’s correlation coefficient. Results: Of 180 participants, 76 (42.2%) were females. The minimum, maximum and mean± standard deviation scores obtained in DR were 4, 14, and 9.031 ± 1.85 and in CBCT were 0,26 and 18.56 ± 4.81, respectively. In the CBCT domain, the participants had maximum knowledge about “low radiation dose” (72.8%) and minimum knowledge about the “role of CBCT in determination of bone density” (45%). In DR domain, the participants had maximum knowledge about “no need for radiographic films” (75.6%) and minimum knowledge about “not requiring manual processing” (15.6%). Overall, participants had higher level of knowledge about CBCT than DR. An inverse correlation was noted between age and work experience with the number of correct answers. However, no significant difference was noted in the knowledge level of males and females regarding CBCT or DR (p = 0.233 and p = 0.227, respectively). Conclusions: further education seem imperative for dentists in this respect for more efficient diagnosis and treatment planning, minimize patient radiation dose and save time and cost.   Keywords Digital radiography; Cone-Beam computed tomography; Knowledge; Dentists.

Background Anatomical analysis of the sphenoid sinus is important because of its proximity to vital neurovascular structures. The aim of this study is investigating the anatomy of the SS and its surrounding structures in CBCT images. Methodology: In this retrospective cross-sectional study, 201 cone-beam computed tomography (CBCT) radiographs were analyzed. The analyzed images included the type of SS, protrusion of ICA and optic nerve and foramen rotundum, vidian canal type, the Onodi cell, pneumatization to surrounding bones, the ostium, the septum. The data were analyzed using chi-square and the t-test in SPSS 24 at a significance level of 0.05. Results The tilted septum had the highest frequency (46.3%). Ostium was bilateral in most images (56.2%). The protrusion of the ICA (54.7%) and optic nerve (62.2%) was smooth in most images. Foramen rotundum protrusion and Onodi cell prevalence were 25% and 22.9%, respectively. The postsellar type of sinus had the highest frequency (71.1%). Vidian canal Grade II had the highest frequency (40.3%). Greater wing pneumatization had the highest frequency (51.7%). No statistically significant relationship was found between the optic nerve protrusion and Onodi cell (P-value < 0.05). There was a significant relationship between the pneumatization of the pterygoid process and the protrusion of the vidian canal, and the foramen rotundum protrusion (p-value < 0.001). Conclusion CBCT imaging is very effective in the anatomical analysis of the SS and its surrounding structures. The postsellar type had the highest frequency.Vidian canal Grade II had the highest frequency; greater wing pneumatization was observed in more than half of the images; the most common type of septum was tilted; ostium was bilateral in most cases; the protrusion of the ICA and optic nerve was mostly smooth.

This study evaluated the effect of different amperage values and voxel sizes of two CBCT scanners on VRF detection in the presence of different intracanal posts. After post‐space preparation, VRFs were induced in half of the samples of 20 maxillary premolars. Five different intracanal posts were passively placed in each root canal. Samples were scanned using CS 9300 and Cranex3D with two different voxel sizes and amperage setting in each unit. The diagnostic sensitivity, specificity and accuracy were compared using the Mann–Whitney and Kruskal‐Wallis tests (α = 0.05). Changes in amperage and voxel size did not affect the detection of VRFs (p ⟩ 0.05). The VRF detection accuracy was the highest in fibreglass and the lowest in nickel‐chromium group. Changes in amperage and voxel size within assessed values do not seem to influence the detection of VRF whereas different intracanal post‐materials have significant effect on VRF detection.