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Background. The upper airway volume is among the factors that affect orthodontic treatment plans. Cone-beam computed tomography (CBCT), as an accurate diagnostic modality, can help assess anatomical structures associated with the upper airway volume.Objectives. This study aimed to use CBCT to determine if there are differences in the upper airway volume between different sagittal and vertical skeletal patterns, considering the hyoid bone position, palatal depth, nasal septum deviation (NSD), and concha bullosa. Material and methods.From among 105 initial CBCT samples retrieved from the archive of a private radiology clinic in Tehran, Iran, 90 CBCT scans of 27 males and 63 females aged 17-65 years were considered in the study according to the inclusion criteria. The upper airway volume was assessed with regard to Angle's classification (using the A point-nasion-B point angle (ANB)), the vertical skeletal dimension (using the sella-nasion plane to mandibular plane angle (SN-MP)), the hyoid bone position, palatal depth, NSD, and concha bullosa, using CBCT and the NNT ® software. The one-way analysis of variance (ANOVA), Levene's test and the t test were used to analyze the data with the SPSS Statistics for Windows software, v. 17.0.Results. The upper airway volume was significantly smaller in long-face cases (p = 0.037). There was no significant correlation between the upper airway volume and Angle's classification, the hyoid bone position, palatal depth, NSD, and concha bullosa.Conclusions. The vertical skeletal dimension was the only parameter that was related to the upper airway volume. The results of this study can be considered while preparing orthodontic treatment plans.

Background and aim: Entrapment of foreign-bodies is a common phenomenon in traumatic events occurring in the maxillofacial region. The purpose of this study was to evaluate the efficiency of panoramic, CT, Cone-beam CT, MRI and ultrasonography in detecting different foreign-bodies in the maxillofacial region. Methods: Four different materials were used as foreign-body including metal, glass, rubber and wood. These particles were prepared in four different sizes from 2*2*2 mm to 5*5*5 millimeters. The foreign-bodies were then implanted into a sheep's head in the infraorbital part of maxilla and mandibular buccal region. The panoramic, CT, Cone-beam CT, MRI and ultrasonography were obtained from the model and the images were blindly observed and analyzed by two radiologists. A four-point scale was used to interpret the visibility of found foreign-bodies. Results: CT had the best efficiency in detecting different foreign-bodies. Cone-Beam CT was the next useful technique. The ability of differentiating the foreign-bodies from the adjacent structures were poor in MRI and ultrasonography. As expected, the panoramic was only efficient in detecting metallic bodies. Conclusion: CT-scan can be introduced as the best imaging modality in detecting different foreign-bodies especially non-metallic ones. CBCT is also acceptable for metal, glass and rubber particles.