Evaluating the anatomical location of the posterior superior alveolar artery in cone beam computed tomography images.

The purpose of this study was to examine the diameter, location, and frequency of the appearance of the posterior superior alveolar artery (PSAA) in preoperative cone beam computed tomography (CBCT) scans. Two hundred and eleven pre-implant CBCT scans were reviewed. The following criteria were considered in all subjects: (1) the location of the artery: intra-sinus or below the membrane (type I), intraosseous (type II), or superficial (type III); (2) the distance between the lower border of the artery and the alveolar crest; (3) the bone height measured from the floor of the sinus to the crest of the ridge; (4) the distance from the lateral wall of the artery to the medial wall of the maxillary sinus; and (5) the diameter of the artery (in millimetres). The distance between the artery and the medial sinus wall, as well as the diameter of the artery, were greater in patients with an alveolar bone height ≤10mm than in those with a bone height >10mm. The distance from the artery to the medial sinus wall and the diameter of the artery were positively correlated with the number of missing teeth. It was also found that the diameter of the PSAA increased with increasing age.

A comparison of the effectiveness of chloroform in dissolving resilon and gutta-percha.

OBJECTIVE: Application of chemical solvents especially in problematic canals is usually a part of the retreatment process. This study was performed to compare the solubility of Gutta-Percha and Resilon in chloroform and to find the effect of sample thickness as well as the time of shaking on their solubility. MATERIALS AND METHODS: Specific weight of Resilon and gutta-percha was placed in a sample tube and after adding 1.0 ml of chloroform at 37ºC, the tubes were capped and shaked for 1, 3 and 5 minutes. The amount of non dissolved material was determined by reweighting of each sample and the percent of solubility was assessed according to the exact weight loss of the samples. The procedure was repeated three times for a given thickness and time of shaking. The difference in the solubility of Gutta-Percha and Resilon as well as the effect of sample thickness and time of shaking on solubility were assessed by repeated measurement ANOVA (p<0.05). RESULTS: Resilon has significantly higher solubility than Gutta-Percha in chloroform (p<0.05). Resilon as well as Gutta-Percha Solubility are increased significantly over the time .The amount of solubility is not affected by sample thickness. CONCLUSION: Comparison of Resilon and Gutta-Percha solubility in chloroform shows that one of the advantages for Resilon could be the chance for using possible safer organic solvents during retreatment.

Evaluation of Correlation between Width and Morphology of Mandibular Inferior Cortex in Digital Panoramic Radiography and Postmenopausal Osteoporosis.

BACKGROUND: In osteoporotic patients, inferior mandibular cortex undergoes resorption which its manifestations can be detected on dental panoramic radiographs as a simple and available method. The aim of this study was to evaluate the correlation between width and morphology of mandibular inferior cortex in digital panoramic radiography and postmenopausal osteoporosis. METHODS: Bone mineral density (BMD) of lumbar vertebrae and femural neck of 119 postmenopause women was assessed using DXA. Width [cortical index (CI)] and morphology [mandibular cortical index (MCI)] of inferior mandibular cortex were measured and the correlations between BMD and width and shape of the inferior mandibular cortex were evaluated. RESULTS: The specificity and sensitivity in identifying women with low BMD of lumbar vertebrae by visual cortical estimation (normal or eroded) were 69.4% and 80.7% respectively. These results in identifying women with low BMD of femural neck were 67.7% and 81.5% respectively. For both sides, the threshold value that provided the highest validity (minimal false negative and false positive results) corresponded to cortical width of 4.29 mm. This threshold in lumbar vertebrae or femural neck provided a sensitivity of 81.4% (95% CI=69.1%-90.3%), specificity of 58.3% (95% CI=44.9%-70.9%), positive predictive value of 65.8% and likelihood ratio of 1.95. There were significant associations between BMD and CI and MCI. CONCLUSION: Postmenopausal women with thin or eroded mandibular inferior cortex may have an increased risk for low BMD or osteoporosis.