ABSTRACT
The relationship between temporal bone pneumatization (TBP) pattern and sinus mucous thickness grading on computed tomography scans of paranasal sinuses was investigated. In this cross-sectional study, a total of 200 temporal bones and paranasal sinuses were evaluated in CT scans of 100 patients with chronic sinusitis (CRS). The mucosal thickness of paranasal sinuses was classified into two groups (0-6 and 7-12) according to the Lund-Mackay (LM) staging system. Also, pneumatization patterns of petrous apex and perilabyrinthine regions were classified according to Jadvah et al. method. Data were analyzed using Chi-square and Fisher's exact tests. The most common pneumatization pattern in the petrous apex was pattern A (49.5%) and in the perilabyrinthine region was pattern B (50%). In the petrous apex, the highest frequencies of pattern A (51.7%) and pattern C (24.6%), among other pneumatization patterns, were found in score range of 7-12 and 0-6, respectively, which was statistically significant (P = 0.017). Although in the perilabyrinthine region, the highest frequencies of pattern A (24.1%) and pattern C (32.7%) were in LM score ranges of 7-12 and 0-6, respectively, no significant difference was found (P = 0.589). The petrous apex pneumatization decreases with an increase in the severity of CRS, which can be in response to the eustachian tube dysfunction and common pathogens with CRS. A similar relationship was also found in the perilabyrinthine region, although it was not statistically significant. No significant relationship between TBP and severity of CRS was found in the age and sex groups.
ABSTRACT
OBJECTIVE: To determine the proper zones for placement of orthodontic mini-screws, based on cone-beam computed tomography (CBCT) measurements in the anterior mandibular region. METHODS: The current cross-sectional study was performed on CBCT images of 77 individuals in the age range of 18-60 years. Axial slices at the levels of 2, 5, and 8 mm from the cementoenamel junction (CEJ) of the mandibular anterior teeth were selected. Interdental distances were measured in the mesiodistal direction, parallel to the midline of the mandibular arch. Areas with more suitable width were investigated for measuring the minimum interdental space. On the reconstructed cross-sectional images, labiolingual thickness of the bone was measured at the levels of 2, 5, 8, and 11 mm from the CEJ. The Kruskal-Wallis test, Mann-Whitney test with Bonferroni correction, Welch test, and Tukey's multiple analogy test were used to analyze the data. RESULTS: Mesiodistal and labiolingual distances between the roots in every measured region had the highest values at the levels of 8 and 11 mm from the CEJ. The highest measured values were related to the interdental region between the lateral incisor and canine teeth on both sides of the arch. There were no statistically significant differences between these values (P < .001). CONCLUSION: The lateral incisor-canine areas at the level of 8 mm from the CEJ are introduced as the optimal sites for placement of orthodontic mini-screws. In addition, the results recommend the application of mini-screws with 1.3-1.7 mm diameter and 5-7 mm length.
ABSTRACT
INTRODUCTION: The purpose of this study was to evaluate the efficacy of cone-beam computed tomography CBCT in the diagnosis of RF in the presence of an intracanal posts with and without applying "metal artifact reduction" (MAR) mode. METHODS AND MATERIALS: This in vitro study included 60 single-canal endodontically treated premolars. Post spaces were created in all roots. RFs were simulated in 30 of the 60 teeth. Dentatus posts were cemented in 15 of 30 roots with and without RFs. Teeth were arranged randomly in 6 artificial dental arches. Images were taken using a Vatech CBCT machine with and without MAR (MAR and WMAR, respectively). A radiologist and an endodontist evaluated the CBCT images for the presence of RFs. Sensitivity, Specificity, positive and negative predictive values were determined for each mode. MC Nemar's and Kappa tests were used for data analysis. RESULTS: The percentage of correct diagnosis using the WMAR mode in both the post space and pin groups in the presence of root fracture was 46.6%; with MAR, it increased to 86.6% and 66.6%, respectively. There was no significant difference between two modes in post space (P=0.503) and metal pin groups (0.549). The overall sensitivity of VRF diagnosis in WMAR mode was 46.67%; in MAR mode, sensitivity was 76.67%. The specificity of WMAR and MAR modes were 60% and 53.33%. The levels of agreement between two modes and real findings were less than 0.45. CONCLUSIONS: There were no significant differences between the efficacies of imaging modes. The sensitivity of the MAR mode for diagnosis of VRF in both the pin and post space groups was higher than the WMAR mode. The specificity of MAR in comparison with WMAR was less or equal in dental groups. The agreement between CBCT and real findings was poor.
