ABSTRACT
PURPOSE: The purpose of this study was to achieve more retention and stability and to delay or prevent screw loosening. MATERIALS AND METHODS: Twenty implants (Implantium 3.4 mm, Dentium, Seoul, Korea) were divided into 2 groups (n = 20). In the first group, an adhesive material was applied around the screw of the abutments (test group). In the second group, the screws are soaked in saliva (control group). All the screws were torqued under 30 N/cm, Then, the samples were gone through a cyclic fatigue loading process. After cyclic loading, we detorqued screws and calculated detorque value. RESULTS: In comparison with the control group, all the implant screws in the test group were smeared with the adhesive material, showing significant higher detorque value. CONCLUSION: There are significantly higher detorque values in the group with adhesive. It is recommended to make biocompatible adhesive to reduce screw loosening.
Subject(s)
Adhesives , Dental Implant-Abutment Design , Dental Implants , Fatigue , Saliva , SeoulABSTRACT
Cancer immunotherapy attempts to stimulate the immune system to reject and destroy tumors and is one of the cancer treatment strategies. Recently, interluekin36 [IL36] has been used as immunotherapeutic agents in cancer gene therapy. Present study investigated that the IL36 gene therapy effects on the regression of tumor masses in mouse model. Aim of this study is determination of the gene therapy effects by IL36 in the regression of tumor masses in mouse model. To study the therapeutic efficacy of this cytokine, WEHI-164 tumor cells were transected with mIL36 plasmids. ELISA test was used to check cytokine production by transected cells. To establish fibro sarcoma mouse model, Tumoral transfected cells were injected subcutaneously to inoculate tumor in BALB/C mice. Tumor volumes were measured by caliper. Mice were sacrificed and tumors were extracted. The expression of IL36 and IFN-gamma was studied with Real-time PCR and immunoblotting. The expression of Ki-67 [a tumor proliferation marker] in tumor masses was studied by immunohistochemistry staining. In this study we had 2 groups which are treated with IL-36 and Untreated with IL-36 as a blank. The group treated with IL36 indicated decrease of tumor mass volume [p<0.001]. The results of western blotting and real-time PCR showed the IL36 expression increased in the group treated with IL36 [with relative expression of 1.9]. Immunohistochemistry staining indicated that the Ki-67expression has been reduced in the group interfered with IL36. IL36 gene therapy has therapeutic effects on the regression of tumor masses in fibro sarcoma mouse model
ABSTRACT
Introduction: Osteon is an alloplastic material containing 70% hydroxyapatite and 30% beta-TCP. Calcitonin, a hormone produced by the thyroid gland, not only prevents bone resorption by reducing both the number and the activity of osteoclasts, but also stimulates bone formation. Considering the favorable effects of calcitonin on bone formation, we hypothesized that the addition of calcitonin to Osteon would result in better bone regeneration. Materials and Methods: To test this hypothesis, full-thickness bone defects were created bilaterally in the femoral condyles of 12 New Zealand white rabbits. The defect was filled with Osteon on one side [the control group]; while on the other side, the defect was filled with a combination of Osteon and calcitonin [the experimental group]. Result: These findings showed that the number of osteoblasts and the degree of calcification in the experimental group were significantly higher than the control group [P = 0.05]. Conclusion: On the basis of these findings, it is plausible to suggest that the addition of calcitonin to hydroxyapatite and beta-TCP as alloplastic materials could contribute to a greater degree of osteogenesis
ABSTRACT
Various computer assisted medical procedures such as dental implant, orthodontic planning, face, jaw and cosmetic surgeries require automatic quantification and volumetric visualization of teeth. In this regard, segmentation is a major step. In this paper, inspired by our previous experiences and considering the anatomical knowledge of teeth and jaws, we propose a hybrid technique for teeth segmentation and visualization in CT volumetric data. The major steps of the proposed techniques are as follows: [1] Separation of teeth in Ct dataset; [2] Initial segmentation of teeth in panoramic projection; [3] Final segmentation of teeth in CT dataset; [4] 3D visualization of teeth. The proposed algorithm was evaluated in 30 multi-slice CT datasets. Segmented images were compared with manually outlined contours. In order to evaluate the proposed method, we utilized several common performance measures such as sensitivity, specificity, precision, accuracy and mean error rate, The experimental results reveal the effectiveness of the proposed method. In the proposed algorithm, the variation level set technique was utilized to trace the contour of the teeth, In view of the fact that this technique is based on the characteristics of the overall region of the tooth image, it is possible to extract a very smooth and accurate tooth contour using this technique. For the available datasets, the proposed technique was more successful in teeth segmentation compared to previous techniques