• Toxicological Research
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• v.33 no.2
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• pp.157-164
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• 2017

This study was to evaluate the age-dependent effects of caffeine exposure on the long bones and reproductive organs using male rats. A total of 15 immature male rats and 15 young adult male rats were allocated randomly to three groups: a control group and two groups fed caffeine with 120 and 180 mg/kg/day for 4 weeks. Exposure to caffeine at either dose significantly reduced body weight gain; a proportional reduction in muscle and fat mass in immature animals, whereas a selective reduction in fat mass with relatively preserved muscle mass in young adult animals. The long bones of immature rats exposed to caffeine were significantly shorter and lighter than those of control animals along with decreased bone minerals. However, there was no difference in the length or weight of the long bones in young adult rats exposed to caffeine. Exposure to caffeine reduced the size and absolute weight of the testes significantly in immature animals in comparison to control animals, but not in young adult animals exposed to caffeine. In contrast, the adrenal glands were significantly heavier in caffeine-fed young adult rats in comparison to control animals, but not in caffeine-fed immature rats. Our results clearly show that the negative effects of caffeine on the long bones and testes in rats are different according to the age of the rat at the time of exposure, and might therefore be caused by changes to organ sensitivity and metabolic rate at different developmental stages. Although the long bones and testes are more susceptible to caffeine during puberty, caffeine has negative effects on body fat, bone minerals and the adrenal glands when exposure occurs during young adulthood. There is a need, therefore, to educate the public the potential dangers of caffeine consumption during puberty and young adulthood.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.1
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• pp.67-76
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• 2008

Implant requires long lasting, strong osseointegration using bio-mechanical interlocking by bone ingrowth. In regarding the size level for bone ingrowth, the micro-patterning would enhance bone response. Micro-patterning can increase the area contacting the bone tissues. Therefore, it may distribute the load to the surrounding bone tissue, more effectively. This study compared and analyzed the load distributing effect with the shape and number of micro-patterning. For the optimal comparison of threads, the assumptions different from general finite element analysis model were made. It was assumed that the implant was axisymmetric and infinitely long. The implant was assumed to be completely embedded in the infinitely long cortical bone and to have 100% bone apposition. The implant-bone interface had completely fixed boundary conditions and received an infinitely big axial load. The condition of threads were as follows. The reference model 1 had conventional thread. Model 2 had 2 micro-patterns on the upper flank of the thread. Model 3 had 2 micro-patterns on the lower flank of the thread. Model 4 had 2 micro-patterns on the upper and lower flanks of the thread. Model 5 had 3 micro patterns on the upper and lower flanks of the thread. The results were as follows: 1. The thread with micro-patterns distributed stress better than the conventional thread. 2. The thread with micro-patterns on the lower flank distributed stress better than that with micro-patterns on the upper flank. 3. The thread with 3 micro-patterns distributed stress better than that with 2 micro-patterns, However, an area with stress concentration occurred.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.2
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• pp.116-126
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• 2018

Purpose: The purpose of this study was to analyze the factors affecting the survival rate and the marginal bone level of dental implants that have functioned over 7-years. Materials and Methods: In 92 patients, 178 dental implants were included. Implant-related factors (diameter, length, prosthetic splint), patient-related factors (gender, smoking, plaque index, compliance to supportive periodontal therapy) and surgery-related factors (proficiency of surgeon, bone graft) were evaluated via clinical and radiographic examination. The marginal bone level was determined by intraoral standard radiography at the mesial and distal aspects of each implant using an image analysis software program. Results: The survival rate of all the implants was 94.94% and the marginal bone level was $0.89{\pm}1.05mm$, these results are consistent with other studies that present long-term good clinical results. Implant length and plaque index among several factors were statistically significant for implant survival rate (P < 0.05). Smoking and the presence of regeneration surgery were statistically significant for the marginal bone level (P < 0.05). Conclusion: Dental implant that have functioned over 7-years showed favorable long-term survival rates and marginal bone level. Implant length and plaque control should be considered for improving the long-term clinical results. It is needed that careful application of bone regeneration technique and smoking control for maintaining of marginal bone level.

• Journal of Periodontal and Implant Science
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• v.46 no.2
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• pp.72-83
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• 2016

Purpose: The goal of this study was to evaluate the long-term success of horizontal alveolar crest augmentation of the retromolar region of the mandible with particulated bone, as well as factors affecting subsequent peri-implant bone loss. Methods: A total of 109 patients (68 female, 41 male) suffering from alveolar ridge deficiencies of the maxilla and mandible were included in this study. All patients were treated with particulated retromolar bone grafts from the mandible prior to the insertion of endosseous dental implants. Mesial and distal peri-implant crestal bone changes were assessed at six time points. Several parameters, including implant survival and the influence of age, gender, localisation of the implant, diameter, covering procedures, and time points of implant placement, were analysed to identify associations with bone level changes using the Mann-Whitney U-test, the Kruskal-Wallis test, and Spearman's rank-order correlation coefficient. Results: A total of 164 dental implants were placed in the maxilla (n=97) and in the mandible (n=67). The mean observation period was $105.26{\pm}21.58$ months after implantation. The overall survival rate was 97.6% after 10 years. Overall, peri-implant bone loss was highest during the first year, but decreased over time. The mean amount of bone loss after 10 years was 2.47 mm mesially and 2.50 mm distally. Bone loss was significantly influenced by implant type and primary stability. Conclusions: The use of particulated autologous retromolar bone grafts is a reliable technique for the horizontal reconstruction of local alveolar ridge deficiencies. Our results demonstrate that implants placed in augmented bone demonstrated similar bone level changes compared to implants inserted in non-augmented regions.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.12 no.1
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• pp.171-179
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• 1990

This is a report on a case of delayed reconstruction after partial mandibularectomy for Ameloblastoma involving symphysis and bodies of the mandible by using of two large pieces of corticocancellous bone blocks obtained from both iliac crests. The authors failed immediate reconstruction with two kinds of Alloplasts(metal, methylmethacrylate) at two times of trial due to known infection and suggestive poor histocompatibility of materials aginst the host who has been suffered from long-term and active pulmonary tuberculosis. However we could get success late reconstruction of this problem-occured and curved area with two pieces of large corticocancellous blocks by using of miniplate osteosynthesis and biphasic external pin fixation. From our experience we are obtained some results as follows : 1. Alloplastic graft materials seemed to be dangerous to maintain successfuly in patient who has a long-term debilitating disease as a active pulmonary tuberculosis. 2. Biphasic external skeletal pin fixation appliance gave many advantages such as maintain functional position of the remained bodies and condyles of the mandible after removal of failed alloplasts and during control of inflammation of this area, assist supportive roles to fix and maintain bone grafts during healing, allow mandibular movement during healing and so offer to conduct normal functional stimuli to bone grafts during osteogenesis etc. 3. Bony union was successful between not only normal bones and grafted bones but also grafted bone pieces even though we used two pieces of large blocks of corticocancellous bone for graft. 4. Miniplate osteosynthesis was not affect any adverse effects to bone grafts but offered good role of fixation and maintenance for bone grafts.

• Archives of Craniofacial Surgery
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• v.11 no.2
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• pp.103-106
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• 2010

Purpose: Giant cell tumors of the bone are rare, locally aggressive lesions that primarily affect the epiphysis of the long bones in young adults. These tumors occur very rarely on the skull, principally in the sphenoid and temporal bones. The occipital bone is an unusual site. We report a rare case of a giant cell tumor of the occipital bone with a review of the relevant literature. Methods: A 7-year-old boy presented with a mass of the right occipital area, which was accompanied by localized tenderness and mild swelling. The mass was first recognized approximately 1 year earlier and grew slowly. There was no significant history of trauma. The physical examination revealed a nonmobile and non-tender bony swelling on the occipital region. The neurological evaluation was normal. The serial skull radiography and CT scan showed focal osteolytic bone destruction with a bulged soft tissue mass in the right occipital bone. The patient underwent a suboccipital craniectomy and a complete resection of the epidural mass. The lesion was firm and cystic. The mass adhered firmly to the dura mater. Results: The postoperative clinical course was uneventful, and the patient was discharged 5 days later. The histopathology report revealed scattered multinucleated giant cells and mononuclear stromal cells at the tumor section, and the giant cells were distributed evenly in the specimen, indicating a giant cell tumor. Conclusion: Giant cell tumors are generally benign, locally aggressive lesions. In our case, the lesion was resected completely but a persistent long term follow up will be needed because of the high recurrence rate and the possible transformation to a malignancy.

• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.2
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• pp.303-311
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• 2013

In this study, we compared the efficiency of osteoblast differentiation media (ODM) containing three distinct reagent combinations in osteoblastic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs) in monolayer culture. In addition, we analyzed growth and differentiation of hBMSCs on silk scaffolds and examined the bone-forming activity of a nanofibrous silk scaffold in a tibia diaphysis defect model of a rat hind limb with intramedullary nailing. Although all three ODM increased alkaline phosphatase activity to a comparable extent, the ODM containing bone morphogenetic protein-2 (BMP-2) was found to be significantly less effective in promoting mineral deposition than the others. Growth of hBMSCs on sponge-form silk scaffolds was faster than on nanofibrous ones, while osteoblastic differentiation was apparent in the cells grown on either type of scaffold. By contrast, bone formation was observed only at the edge of the nanofibrous scaffold implanted in the tibia diaphysis defect, suggesting that use of the silk scaffold alone is not sufficient for the reconstitution of the long bone defect. Since silk scaffolds can support cell growth and differentiation in vitro, loading MSCs on scaffolds might be necessary to improve the bone-forming activity of the scaffold in the long bone defect model.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.3
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• pp.283-290
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• 2000

State ment of Problems. Although some clinicians report long-term success with fixed partial denture (FPD) that contain cantilever pontic, the use of cantilever FPDs may be hazardous because of unfavorable leverages during mastication. Purpose of Study. This study aims to compare the stress induced in the periodontium with normal and reduced bone support, and to analyze the stress distribution patterns of anterior cantilevered FPDs using the finite element method. Results. Cantilever bridge with a reduced bone level generated the highest peak stresses in the periodontium. In the models of reduced bone support, a cantilever bridge exhibited the great-est mobility and a 3-unit fixed restorations induced the smallest mobility of canine. The highest peak stress level of a 3-unit bridge in the periodontium is similar to the unrestored situation. But stress distribution in the bone is modified. Conclusion. In reduced bone support, a cantilever bridge exhibited the greatest mobility and stress.

• The Korean Journal of Nuclear Medicine
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• v.38 no.4
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• pp.275-281
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• 2004

Compared with the earlier technique of dual photon absorptiometry (DPA) using $^{153}Gd$ radionuclide source, dual energy X-ray absorptiometry (DXA) has advantages of higher precision, accuracy and shorter scanning time. Despite the change from DPA to DPX, the nuclear medicine physicians has remained one of major suplier of this service due to long-standing use of DPA. Among many kinds of bone densitometries, DXA is the "gold standard" for the noninvasive diagnosis of osteoporosis. Especially there is no role for peripheral devices in the monitoring of patients on therapy. But, there are some areas of controversy related to the application of DXA, such as proper site of measurement, accurate interpritation, appropriate use of T-score, and the reference population young database. And the accuracy, precision, and quality control issues relating to bone density measurement are important subjects. To address these issues, the International Society for Clinical Densitometry (ISCD) has convened two Position Development Conferences and addressed official positions. This review deals the key elements of ISCD position paper and other important issues on the management of bone densitometry.

• The Korean Journal of Nuclear Medicine
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• v.13 no.1_2
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• pp.55-60
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• 1979

The radiographic diagnosis of osteomyelitis can be suspected early with deep soft tissue swelling, but the actual bone changes of osteomyelitis may be delayed as long as 10 to 14 days after onset or may be totally aborted by antibiotic therapy. Recognition of osteomyelitis by bone imaging is far more rapid than by conventional radiographic examination and can be used on admission to establish the diagnosis. Ten patients suspected of having early, acute osteomyelitis were studied by TC-99m Pyrophosphate bone imaging. Radiographs taken at the same time were all negative. Of these 9 patients showed positive bone images. The bone imaging provides a safe, accurate, noninvasive technique for the early diagnosis of osteomyelitis.