Background:The optimal position of the condyle in glenoid fossa is a fundamental question in dentistry. There is no quantitative standard for the optimal position of mandibular condyle in the glenoid fossa in our population. The purpose of this study is to assess the position of the condyle by cone beam computed tomography (CBCT) images in patient with normal function of temporomandibular joint (TMJ).Materials and Methods:In this cross-sectional study, CBCT images of 40 class I skeletal patients (15 males and 25 females) without history of TMJ disorders were selected. Next, the anterior, superior and posterior joint spaces (Ajs, Sjs, Pjs) were measured on the two true central sagittal slices. Then medial (M) and lateral (L) joint spaces on true coronal view were measured in the right and left sides, separately. After that, P/A ratio, S/A ratio and M/L ratio were calculated. Finally, a paired t-test and independent samples t-test were employed for analysis.Results:The centric position of the condyle in glenoid fossa was more common (92.5%) than other positions. Significant differences in Ajs, Sjs, Pjs, Mjs and Ljs values between two sides were observed (P ≤ 0.05). Additionally, Sjs showed statistically significant differences between the sexes (P = 0.05). P/A ratio and S/A ratio had significant differences between two sides but not between those sexes.Conclusion:The assessment of joint spaces in right and left sides should be done independently. Overall, the measured joint spaces except Sjs are not different in two sexes. The data from this study could be a useful and comparable reference for the clinical assessment of condylar position in patients with normal functional joints.

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PurposeField of view and voxel resolution of cone beam computed tomography (CBCT) might affect the diagnostic capability. This study was performed to compare between the standard and HiRes zoom modes in the diagnosis of external root resorption (ERR) using CBCT.Materials and MethodsSixty three small cavities (0.25 mm depth and 0.5 mm diameter) were simulated on the buccal, lingual, and proximal surfaces at three different levels of 16 roots of teeth. After covering the root with nail varnish, the roots were inserted in the sockets and the model was placed in a water-containing lacuna. CBCT scans were taken in both standard and HiRes zoom modes using NewTom VG (QR srl Company, Verona, Italy). Then, an observer assessed the images to determine the presence or absence of the cavities. This process was repeated by increasing the size and depth of cavities to 0.5 mm depth and 1 mm diameter. Data were analyzed by McNemar test. The sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio in evaluation of the simulated cavities were calculated.ResultsThere was a significant difference between the two imaging modes in diagnosing the shallow cavities (p=0.02).The sensitivity of the standard zoom in detecting the shallow cavities was lower than that of the HiRes zoom. The likelihood ratio of the HiRes zoom was higher in the diagnosis of both cavity types.ConclusionThis study suggested that a smaller voxel size in the HiRes zoom mode of CBCT is preferred for diagnosis of ERR.

Background:Preoperative radiographic evaluation of impacted third molars is essential to determine the proximity to the mandibular canal to minimize the risk of nerve injury. Our study aim was to evaluate the relationship between the mandibular canal and impacted mandibular third molars using cone beam computed tomography (CBCT) and to compare findings therein with panoramic radiographic signs.Methods:CBCT images were taken from 29 patients having 43 Class C impacted mandibular third molars whose panoramic radiographs showed a close relationship between the mandibular canal and mandibular third molars. We evaluated their tomographs to determine the course of the canal, its proximity to the root, any narrowing of the canal, the presence of root grooving or hooks and the proximity of the root to the cortex. A Chi-square test was used for data analysis.Results:The lingual course of the canal was the most frequently detected course in all panoramic findings. Contact of the tooth with the canal was observed in all cases in which panoramic signs of deviation of the canal and darkening of the roots were found. The frequency of observing the narrowing of the canal in CBCT as compared to seeing the presence or the absence of canal narrowing in panoramic radiographs was significantly different (P=0.01).Conclusion:CBCT provides more precise diagnostic information to determine the relationship of impacted third molars to the canal. Deviation of the canal and darkening of the roots in panoramic view can be highly valuable to predict the risk of nerve injury.

Neurofibroma is an autosomal dominant disorder which has major criteria such as hyperpigmentation (cafe-au lait spots), cutaneous and subcutaneous tumors and bone deformities. In this report, a case of multifocal intraosseous neurofibroma in a 16-year-old male with right facial asymmetry, multiple unerupted maxillary posterior teeth and a previous history of infratemporal and orbital neurofibroma is presented. The majority of reported cases occurred in the posterior portion of the mandible and a limited number in the maxilla. Cone beam CT (CBCT) was performed for better evaluation of the extension and form of the maxillary and mandibular lesions. This report presents a rare situation of simultaneous peripheral neurofibromatosis (NF) and multifocal intraosseous NF in the mandible, maxilla and orbits and also focuses on advanced imaging findings of bony and soft tissue neurofibroma.