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.

ObjectivesThe aim of this study was to evaluate different anatomical variants of the anterior loop of the inferior alveolar nerve (IAN) via cone-beam computed tomography (CBCT).Materials and MethodsCBCT images of 71 patients (36 males and 35 females) were evaluated. We used the classification described by Solar for IAN evaluation. In this classification, three different types of IAN loops were introduced prior to emerging from the mental foramen. We classified patients according to this system and introduced a new, fourth type.ResultsType I was seen in 15 sites (10.6%), type II in 39 sites (27.5%), and type III in 50 sites (35.2%). We found a new type in 38 sites (26.8%) that constituted a fourth type.ConclusionWe found that type III was the most common variant. In the fourth type, the IAN was not detectable because the main nerve was adjacent to the cortical plate and the incisive branch was thinner than the main branch and alongside it. In this type, more care is needed for surgeries including inferior alveolar and mental nerve transposition.

Objectives: Pericoronal radiolucencies are common pathologic findings in regular dental checkups. Since dentigerous cyst is the most common pathologic pericoronal radiolucency and as odontogenic keratocyst (OKC) is a common cyst also and an aggressive lesion with high recurrence, radiographic features of these lesions were discussed in this study using panoramic radiography and cone beam computed tomography. Materials and Methods: In this cross-sectional case series study, radiographs from 56 patients who were referred to a private maxillofacial radiology center or dentistry faculty in Mashhad/Iran from 2008 to 2013 in which radiolucent pericoronal lesion was observed in jaws with histopathologic results of dentigerous cyst or OKC were separately examined by two maxillofacial radiologists. Both observers were unaware of pathology results. Lesions were assessed based on their location, periphery, and impaction on the surrounding structures. Then, obtained data were analyzed using descriptive tables. Results: 56 lesions were identified in 56 patients. There were 20 odontogenic keratocyst and 36 dentigerous cysts. The majority of dentigerous cysts and OKCs occurred in the posterior mandible and showed a well corticated border. External root resorption was higher in OKC cases. In addition, displacement tendency of surrounding structures (other than tooth) such as nasal floor, mandibular canal, buccal and lingual cortex (in the form of expansion) as well as destruction of cortex, nasal floor or sinus walls was higher in OKC than in dentigerous cyst. Conclusion: Except of tooth displacement other parameters related to the effect on surrounding structures in this study showed higher frequency in OKC than dentigerous cyst.

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