• The Journal of the Korean dental association
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• v.45 no.9 s.460
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• pp.562-570
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• 2007

Many dentists and patients expect that implant function and esthetics will not change over time. However, even the most successful implant restorations with ideal position, vertical height, and occlusion can be aesthetically pleasing, but may hide a common problem. Many dentists noticed that there can be some circumferential bone loss around the neck of the implants. To circumvent this bone loss, a "platform switching" concept was introduced recently. The basic concept of platform switching is by moving the fixture-abutment interface further away from the crestal bone to minimize crestal bone loss. Since crestal bone loss is a multifactor problem, it is important to consider microgap formation and micromotion between the implant and abutment because platform switching does not solve the problem on its own. In this article, we reviewed studies concerning platform switching and discussed the clinical application and the problems that may occur with its use.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.927-932
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• 2016

Bone morphogenetic proteins (BMPs), belonging to the transforming growth factor-${\beta}$ superfamily, regulate many cellular activities including cell migration, differentiation, adhesion, proliferation and apoptosis. Use of recombinant human bone morphogenic protein-2 (rhBMP-2) in oral and maxillofacial surgery has seen a tremendous increase. Due to its role in many cellular pathways, the influence of this protein on carcinogenesis in different organs has been intensively studied over the past decade. BMPs also have been detected to have a role in the development and progression of many tumors, particularly disease-specific bone metastasis. In oral squamous cell carcinoma - the tumor type accounting for more than 90% of head and neck malignancies- aberrations of both BMP expression and associated signaling pathways have a certain relation with the development and progression of the disease by regulating a range of biological functions in the altered cells. In the current review, we discuss the influence of BMPs -especially rhBMP-2- in the development and progression of oral squamous cell carcinoma.

• Imaging Science in Dentistry
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• v.39 no.4
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• pp.205-208
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• 2009

Aneurysmal bone cyst (ABC) is relatively rare, non-neoplastic expansile lesion of bone. The case of a IS-year-old male with a ABC of the left mandibular condyle is presented. Panoramic radiograph showed a unilocular radiolucency with thinned coritces and a subcondylar fracuture which was due to the trauma. Computed tomography (CT) revealed expansile lesion which had similar attenuation soft tissue. The patient was treated surgically including iliac crestal bone graft.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3943-3952
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• 2009

This study investigated the changes in bone mineral density(BMD) and biochemical bone turnover markers over 1 year in healthy young college women. In comparison of changes in BMD at the lumbar spine, proximal femur (trochanter, femoral neck, Ward's triangle), and whole body over 1 year, there was only a significant difference in that at forearm. However, serum osteocalcin, a marker of bone formation, and urinary deoxypyridinoline, a marker of bone reabsorption, were significantly changed over 1 year. These findings indicate that although BMD does not significantly change in early young adult, the changes of bone metabolism markers seem to mean active bone turnover in early young adult women.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.3
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• pp.21-30
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• 1994

The relationship between bone mineral density and the environmental factors were investigated from the view point of preventing osteoporosis in Korean pubescent girls. The effects of calcium, nutrient intake, physical activity on total bone mineral density, lumbar spine and femoral bone mineral density and total bone mineral content were evaluated 33 healthy pubescent girls aged 14∼16y. A convenient method was used to assess nutritional and energy intake and calcium index was used together. Calcium intake in childhood was estimated by asking whether subjects usually drank milk as children. Eating habits data and history of menstruation were obtained by questionnaire and interview. Average energy expenditure was calculated. Bone mineral density and content were measured by dual energy x-ray absorptiometry using a Lunar DPX＋Scanner (Lunar, Madison, WI). The lumbar spine(L2∼L4) and three sites in the proximal femur (femoral neck, trochanteric region, and Ward's triangle)were measured. Height and weight were measured, and the body mass index(BMI) was derived from the formula : BMI=kg/㎡ Statistical analysis was performed by simple correlation using the SAS package. The mean calcium intake (736mg) was below the RDA of 800mg/d. Twelve percent of the total subjects did not drink milk at all because they did not like the taste. Skipping meals, low calcium intake and low energy intake were significantly correlated with the low BMD. Also the data indicate that girls who reported drinking milk with every meal during childhood had significantly higher bone densities than girls who reported drinking milk less frequently. The results suggest that milk consumption in childhood appears to be needed not only for growth and development, but possibly also to assure an optimal peak of bone mass and thus greater latitude for the maintenance or skeletal integrity in the face of bone losses. There was a highly significant correlation between the total BMD and overall level of physical activity. Body weight was a better predictor of total BMD than was and other factor. Simple mechanical loading may explain why body weight, but total BMC was positively relatd to height. Conclusively, increasing calcium intake and physical activity in the pubescent girls could influence BMD.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.4
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• pp.573-592
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• 1994

A two-stage procedure is ideal for getting a successful osseointegration. But if a one-stage procedure can achieve a similar osseointegration, the one-stage procedure has several advantages. The purpose of this study was to observe the initial bone formation and bone remodeling of open type (nonsubmerged) and closed type (submerged) titanium implants. Eight ITI hollow-screws and eight Branemark fixtures were divided into two groups (submerged and nonsubmerged) and were installed on the lower jaws of four mongrel dogs. The animals were sacrificed three months later and bone sections with implants were processed for light microscopic and fluorescent microscopic observation. The results were as follows : 1 There was no significant difference in bone-to-implant contact between submerged and nonsubmerged implants. 2. Smooth surface titanium implants showed more bone-to-implant contact than that of titanium plasma coated implants histologically. 3. Under fluorescent microscopy, the active bone remodeling and new bone formation were observed in the interface zone. 4. Under fluorescent microscopy, submerged and nonsubmerged implants had no difference in bone remodeling pattern, and intramembranous bone formation was more prominent. 5. The connective tissue fibers orienting perpendicularly toward implant surface were oberved in the neck of implants.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.823-830
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• 2010

This study was designed to examine the morphological measurement and characteristics of trabecullae based on femoral radiographic image for prediction of osteoporosis. Study subjects were 34 females (average age of 62.1 years) and 6 males (average age of 60.1 years), they were categorized into normal group and osteoporosis group in accordance with the T-score value. Measurement of the bone density of femoral bone was measured with DEXA(Dual Energy X-ray absorptiometry). ROI(Region of interests) was selected on femoral neck and trochanter. Characteristics of trabecullae was analyzed by using the skeletonization analysis of trabecular image. Morphological measurement was analyzed through femoral radiographic image in order to examine the correlation with osteoporosis. The result demonstrated statistically significant correlation between neck cortical thickness, shaft width, shaft cortical thickness, periphery, mean gray level and trabeculae area with BMD average (T-score) of femoral part. The results show that morphological measurement and characteristics of trabecullae based on femoral radiographic images for osteoporosis prediction could be effective.

• Korean Journal of Veterinary Research
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• v.35 no.4
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• pp.643-649
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• 1995

An abnormal Korean native cow of six years old with extra legs was observed macroscopically and radiographically. The results were summarized as follows; 1. External features included two normal forelimbs and hindlimbs, and two extra forelimbs which were underdeveloped. The extra forelimbs of different length attached laterally to the cranial regions of neck on right scapula. 2. The large extra forelimb had scapular meromelia. It consisted of underdeveloped humerus, antebrachial skeleton, several carpal bones, metacapal bone(MC3+4) and two digitis with each pairs of hoof and a rudimentary hoof of dewclaw. 3. The small extra forelimb had scapular and antebrachial meromelia. It consisted of underdeveloped metacarpal and carpal bone, severely deformed humerus, fused carpal bones, and two digitis with two hooves, and a rudimentary hoof of dewclaw. 4. The dermoid cyst was observed between the large and small extra forelimbs.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.2
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• pp.136-142
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• 2004

Malignant fibrous histiocytoma(MFH) is the malignant part of mesenchymal cell-originated tumor, which is supposed that the tumor is presented various histologic features consisted of fibrosarcomatic and histiocytic portions. When the tumor is arisen in the head and neck region, the most affected sites are the nasal cavity and paranasal sinuses, and secondly the maxillary alveolar bone is occasionally influenced. Therefore, MFH can readily involve the adjacent alveolar bone. The treatment of MFH in the head and neck is various, that is, the involved sites and the differentiation of tumor must be considered when the tumor is treated. The treatment protocols are subjected to general ones of soft tissue sarcoma, and simple or combination therapy is used in the surgery, chemotherapy and radiation therapy. So, we report a clinical case of chemotherapy involving intraarterial chemotherapy, and surgery of malignant fibrous histiocytoma(MFH) in the maxilla, with review of the literature.

• Korean Journal of Head & Neck Oncology
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• v.19 no.2
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• pp.179-183
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• 2003

Osteosarcoma is one of the most frequently occurring malignant bone tumor except for multiple myeloma. However, osteosarcoma of the mandible is rare and aggressive malignancy constituting about 5% to 13% of all cases of skeletal osteosarcoma. The authors experienced a case of osteosarcoma of the mandible in a 31-years old male patient. He visited our outpatient clinic with painless mass of the cheek. On the basis of the clinical and imaging findings, the differential diagnosis included giant cell tumor, histiocytosis and malignant bone tumor. In the first operation, the mass of the mandible was excised. Intraoperative microscopic examination of a frozen section did not yield a diagnosis: however, the final definitive histologic examination revealed osteoblastic osteosarcoma. After 15days, wide excision with hemimandibulectomy was completed followed by postoperative radiotherapy and chemotherapy. With our experience, we report the progression of diagnosis and management for mandibular osteosrcoma.