• Journal of Periodontal and Implant Science
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• 제47권1호
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• pp.20-29
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• 2017

Purpose: The microstructural characteristics of trabecular bone were identified using micro-computed tomography (micro-CT), in order to develop a potential strategy for implant surface improvement to facilitate osseointegration. Methods: Alveolar bone specimens from the cadavers of 30 humans were scanned by high-resolution micro-CT and reconstructed. Volumes of interest chosen within the jaw were classified according to Hounsfield units into 4 bone quality categories. Several structural parameters were measured and statistically analyzed. Results: Alveolar bone specimens with D1 bone quality had significantly higher values for all structural parameters than the other bone quality categories, except for trabecular thickness (Tb.Th). The percentage of bone volume, trabecular separation (Tb.Sp), and trabecular number (Tb.N) varied significantly among bone quality categories. Tb.Sp varied markedly across the bone quality categories (D1: $0.59{\pm}0.22mm$, D4: $1.20{\pm}0.48mm$), whereas Tb.Th had similar values (D1: $0.30{\pm}0.08mm$, D4: $0.22{\pm}0.05mm$). Conclusions: Bone quality depended on Tb.Sp and number-that is, endosteal space architecture-rather than bone surface and Tb.Th. Regardless of bone quality, Tb.Th showed little variation. These factors should be taken into account when developing individualized implant surface topographies.

• Journal of Periodontal and Implant Science
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• 제38권1호
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• pp.75-82
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• 2008

Purpose: The purpose of this study was to evaluate exophytically vertical bone formation in the mandibular premolar area of beagle dogs by the concept of guided bone regeneration with a titanium reinforced e-PTFE membrane combined with human demineralized freeze-dried bone. Materials and Methods: Four one-year old beagle dogs were divided into control and experimental group. All mandibular premolars were extracted and surgical vertical defects of 5 mm in height were created in the extracted sockets. At 8 weeks after the extraction, TR e-PTFE membrane sized with 8 mm in length, 5 mm in width, and 4 mm in height was placed on the decorticated mandible, fixed with metal pins and covered with full-thickness flap and assigned as control group. In experimental group, decorticated mandibule was treated with TR e-PTFE membrane and human demineralized freeze-dried bone. The animals were sacrificed at 16 weeks after the regenerative surgery, and new bone formation was assessed by histomorphometric as well as statistical analysis. Results: Average of new bone formation was 38% in the control group, whereas was 25% in the experimental group (p<0.05). Average of connective tissue formation was 42% in the experimental group, whereas was 30% in the control group (p<0.05). The lamellar bone formation with haversian canals was observed in the both groups. In the experimental group, the particles of human demineralized freeze-dried bone were observed after 16 weeks and complete resorption of graft was not observed. Conclusion: On the basis of these findings, we conclude that titanium reinforced e-PTFE membrane may be used alone for vertical guided bone regeneration, but demineralized freeze-dried bone has no additional effect on vertical guided bone regeneration.

• 한국의학물리학회지:의학물리
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• 제6권2호
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• pp.111-125
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• 1995

뼈는 주변 여건에 따라 뼈의 재질 및 형상이 변하는 일종의 동적 구조물로서, 보철물이 부착되면 뼈의 응력상태가 다라져 새로이 골재형성을 하게 된다. 특히, 골절판 부착시 뼈의 접촉은 촉진되나, 그 부위의 응력 변화에 의하여 골절판과 부착된 부분의 뼈는 오히려 약화되는 골다공증 현상을 야기하기도 한다. 본 연구에서는 뼈의 응력변화와 골재형성의 관계를 3차원 유한 요소법을 이용하여 관련시키고자 한다. 이는, 새로이 설계된 골절판 또는 어떤 보철물이, 비록 그 자체의 생체 적합성 및 충분한 강도를 갖게 되더라도 골재형성에 미치는 영향을 판단할 근거가 요구된다고 사료되기 때문이다. 그래서, 현 사용되는 골절판을 인체 대퇴골에 부착된 3차원 유한 요소 모델을 제작하여, 응력 차이법에 의한 골재형성의 경향을 조사하고, 그 경향을 기존 동물 실험결과와 비교 검토하여, 본 연구의 타당성을 평가하여 보철설계의 역학적 기초를 확립하고자 한다.

• Advances in biomechanics and applications
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• 제1권1호
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• pp.15-22
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• 2014

Computed tomography (CT) is being utilized in orthopaedics and related research to estimate bone strength. These applications benefit from calibration of Hounsfield units to mineral density typical of long bone, up to $1750mg/cm^3$. This study describes a method for establishing repeatable calibration of Hounsfield units to density, and determines the effects of imaging medium on calibration accuracy. Four hydroxyapatite standards were imaged in air on 7 occasions over 19 weeks using a helical multi-slice CT scanner. Each standard was scanned 5 times in different media: porcine soft tissue, water, and air. Calibrated densities were highly repeatable (CV<3.5%). No difference in density was observed between water and soft tissue conditions (p>0.08). This work provides a model for determining repeatable scanner-specific density calibration, demonstrates that the linear relationship between Hounsfield units and density extends to values typical of cortical bone, and supports the practice of imaging calibration standards in an environment similar to that of the target bone.

• 한국정밀공학회지
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• 제25권9호
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• pp.126-134
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• 2008

Kendo is one of the popular sports in modem life. Head, wrist and thrust attack are the fast skill to get a score on a match. Human muscle skeletal model was developed for biomechanical study. The human model was consists with 19 bone-skeleton and 122 muscles. Muscle number of upper limb, trunk and lower limb part are 28, 60, 34 respectively. Bone was modeled with 3D beam element and muscle was modeled with spar element. For upper limb muscle modelling, rectus abdominis, trapezius, deltoideus, biceps brachii, triceps brachii muscle and other main muscles were considered. Lower limb muscle was modeled with gastrocenemius, gluteus maximus, gluteus medius and related muscles. The biomechanical stress and strain analysis of human muscle was conducted by proposed human bone-muscle finite element analysis model under head, wrist and thrust attack for kendo training.

• Archives of Plastic Surgery
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• 제32권4호
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• pp.467-473
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• 2005

Calvarial bone grafting in craniomaxillofacial trauma and facial reconstructive surgery is now widely recognized and accepted as a standard procedure. One of the commonly reported problems of calvarial bone graft is the contour defect caused by partial resorption of the graft. But, there are few reports that discuss the fate of the calvarial bone graft based on the quantitative data. In this article, the changes of grafted calvarial bone were evaluated using 3-dimensional computed tomography(CT). 9 patients were observed with the CT scans at 2mm thickness immediately after operation and at the time of last follow-up. The area of the bone defect was segmented on the 3-dimensional CT image and calculated by AnalyzeDirect 5.0 software. The immediate postoperative bone defect area of the recipient site and the donor site were $612.9mm^2$ and $441.5mm^2$, respectively, which became $1028.1mm^2$ and $268.8mm^2$, respectively at the last follow-up. In conclusion, the bone defect area was less increased on the donor site of calvarial bone graft than on the recipient site. And the CT scan is a valuable imaging method to assess and follow-up the clinical outcome of calvarial bone grafting.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제14권3호
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• pp.245-253
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• 1992

To evaluate the tissue response of demineralized and undimineralized xenogeneic bone-martrix graft in extraskeletal site, we prepared human bone as a implant matrix, and outbred mouse as a recipient. Before clinical application of bank bone of human in Wonkwang university, we should confirm the allogeneic bone grafts us a biologically useful bone graft substitutes, obtanined from the patients receiving oral and maxillofacial surgery. The clinical evaluation and histologic studies showed that both (demineralized and undemineralized) xenogeneic bone matrix grafts were not rejected and that they seemed to stimulate new bone formation at the transplanation site. Undemineralized xenogeneic bone marb6 grafts showed minimal bone induction and gradual demineralization with slow resorption and showed that the differentiation of cells showing fibroblastic activity adjacent to the sop tissue were slowly and less frequently than demineralized bone. Characteristical differences between the demineralized and undemineralized matrix were the appearance of foreign body giant cells (multinucleated giant cells) and the evidence of sloe resorption in undemineralized bone matrix.

• 한국임상수의학회지
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• 제39권2호
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• pp.59-64
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• 2022

A dog aged two years and seven months and a cat aged seven years were referred owing to fractures of long bones. Preoperative radiographs revealed comminuted bone fractures close to joints. Conventionally, long-bone fractures are treated using intramedullary pins, plate and screw systems, or an external fixator system. In cases of non-reducible fractures, various graft materials have been used in fracture treatments to stimulate bone repair. Here, recombinant human bone morphogenetic protein-2 (rhBMP-2) and a collagen membrane were applied. Four weeks after surgery, fractured bone fragments began to unite and the bone union was observed using radiography four months after surgery. No complications occurred related to grafted materials. We successfully applied rhBMP-2 and collagen membranes in two different species to support the healing process of comminuted fractures, according to the concept of guided bone regeneration.

• 한국임상수의학회지
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• 제39권6호
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• pp.302-310
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• 2022

Recently, in human medicine and veterinary medicine, interest in synthetic bone graft is increasing. Among them, bone morphogenic protein (BMP) is currently being actively researched and applied to clinical trials. However, BMP has the disadvantage of being expensive and easily absorbed into surrounding tissues. Therefore, BMP requires the use of small amounts and rhBMP (recombinant human bone morphogenetic protein)-2 carriers that can be released slowly. Hydrogel has the property of swelling a large amount of water inside when it is aqueous solution, and when it is, it consists of more than 90 percent water. Using these properties, hydrogels are often used as rhBMP-2 carrier. The scaffold used in this study is a hydrogel made from which keratin is extracted using human hair and based on it. In this study, we wanted to see the effect of bone formation in the calvarial defect model by using keratin-based hydrogel made with human hair as a scaffold. The experiment was conducted by dividing 3 groups a total of 12 mice. Calvarial bone defect is set to all 4 mm diameters. Bone formation was evaluated by using gross evaluation, micro-computed tomography (micro-CT), immunohistochemistry. Groups using keratin-based hydrogel were significantly observed compared to Group 1s, and the most bone formations were found when rhBMP-2 and hydrogel were used. This represents the superiority of the functions of the rhBMP-2 carrier by a new material, keratin-based hydrogel. Through gross evaluation, micro-CT, and immunohistochemistry, we can confirm that keratin-based hydrogel is a useful rhBMP-2 carrier.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제36권2호
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• pp.37-49
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• 2014

Purpose: This study compares the bone formation ability of tricalcium phosphate (TCP) with and without recombinant human bone morphogenetic protein-2 (rhBMP-2) and assesses TCP as a carrier of rhBMP-2. Methods: Bilateral round defects (diameter: 8.0 mm) were formed in the cranium of eight New Zealand white rabbits. The defects were grafted with TCP only (control group) or with rhBMP-2-coated TCP (experimental group). The animals were sacrificed at 1st week, 2nd week, 4th week, and 8th week postoperatively; two rabbits sacrificed each time. The skulls were harvested and subjected to radiographic and histological examination. Results: Radiologic evaluation showed faster bone remodeling in the experimental group than in the control group. Histologic evaluation (H&E, Masson's trichrome stain) showed rapid bone formation, remodeling and calcification in the 1st and 2nd week in the experimental group. Immunohistochemical evaluation showed higher expression rate of osteoprotegerin, receptor activator of nuclear factor ${\kappa}B$ ligand, and receptor activator of nuclear factor ${\kappa}B$ in the experimental group at the 1st and 2nd week than in the control group. Conclusion: rhBMP-2 coated TCP resulted in rapid bone formation, remodeling, and calcification due to rhBMP-2's osteogenic effect. TCP performed properly as a carrier for rhBMP-2. Thus, the use of an rhBMP-2 coating on TCP had a synergic effect on bone healing and, especially, bone remodeling and maturation.