Rhinolith: An Incidental Finding in a Patient Under Orthodontic Treatment

Objectives Rhinolith is an uncommon condition that results from calcification of an endogenous or exogenous nidus within the nasal cavity. It may present asymptomatically or cause symptoms like headache and nasal obstruction. Case: In this case report, we present a case of an unusual and quite big rhinolith in a 17-year-old male which was undetected for some time, and was accidentally found in the radiographic examination. It possibly originated from a retained foreign body in childhood. We discuss its clinical and radiographic features and its effect on the surrounding structures. Conclusion Radiographic assessment and rigid endoscopy are important to evaluate the rhinolith's location

Effect of Head Position on Linear Cephalometric Measurement Accuracy of Cone-Beam Computed Tomography

Objective This study aimed to assess the effect of head position on linear cephalometric measurements by cone-beam computed tomography (CBCT). Methods: CBCT scans of four human dry skulls were obtained by NewTom 3G volume scanner with alarge (15 x15 cm)field of view in 1 centric and 18 eccentric positions: 10°, 20°, and 30° tilt (right and left), 10°, 20°, and 30° rotation (right and left), 10°, 20°, and 30° extension and 10°, 20°,and 30° flexion. The distances between the selected landmarks namely the Nasion (N), Sella (Se), anterior nasal spine (AN S), Menton (Me), Gnathion (Gn), Gonion (Go), and Condylion (Co) were measured by two observers on maximum intensity projection reconstructions using the NNT Viewer software, and compared with the actual measurements (gold standard). The inter-class correlation coefficient (ICC) and the student’s t-test were used for statistical analysis. Results The mean inter-rater agreement was excellent for all head positions (ICC=96.89%). The maximum error in absolute mean measurements was 2.56 mm (P=0.03) The minimum error was for the N-Me line, which is a vertical line closest to the midline. Conclusion The greatest error was observed in 30° left ward rotation for the left CoGn linear measurement. Although this level of error may not be of clinical significance, it is suggested that clinicians acquire the scans in ideal head position to minimize distortion and errors

Diagnostic Accuracy of Reverse Contrast Enhancement for Detection of Vertical Root Fractures

Objectives Vertical root fracture (VRF) is a common complication in endodontically-treated teeth. Due to its poor prognosis, a valid and reliable detection method is imperative for treatment planning. The aim of this study was to evaluate the application of reverse contrast in diagnosis of VRF by digital radiography. Methods Fifty extracted single-rooted premolar teeth were selected for this in-vitro experimental study. The teeth were mounted in a dry mandible and fixed with wax. Radiographs were obtained of all teeth with 0° horizontal angle, and 0° and +15° vertical angle. VRFs were then created by a hammer in vertical direction. Radiographs were obtained again as previously described. Radiographs of each tooth were evaluated twice: once without reverse contrast and then with reverse contrast 2 weeks later. The weighted kappa coefficient was calculated to assess the inter-observer agreement. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR+) and negative likelihood ratio (LR-) were compared in use and no use of reverse contrast using the Cochrane Q test. Results Radiographic angle had no significant effect on the diagnostic accuracy in use or no use of reverse contrast, except for the sensitivity value in no use of reverse contrast which was significantly higher in 15° vertical angle. The diagnostic accuracy of images enhanced with reverse contrast had no significant difference with original images in 0° and 15° vertical angles.   Conclusion Radiographs enhanced with reverse contrast had no significant difference with original radiographs for diagnosis of VRFs. Thus, for detection of VRFs, reverse contrast should only be considered as an adjunct