• Archives of Plastic Surgery
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• 제35권1호
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• pp.7-12
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• 2008

Purpose: Since the report of artificial dermis manufacturing method using collagen by Yannas in 1980, collagen has been effectively used as dermal substitute with its merits such as, lower antigeneicity, controllable biodegradation rate, and minimal inflammatory cytotoxic properties in the dermal tissue engineering field. However, weak mechanical durability was the main drawback of collagen dermal substitute. To improve its stability, mechanical or chemical cross-linking was used. Despite of such process, its clinical use was restricted due to weak durability. To improve the durability of collagen matrix, we designed elastin-incorporated collagen matrix and compared its durability with conventional collagen matrix. Methods: 15mm diameter with 4mm thick collagen dermal matrix was made according to Yannas protocol by mixing 0.5% bovine collagen and chondroitin-6-sulfate followed by degassing, freeze drying, dehydrodermal cross-linking and chemical cross-linking procedure. In elastin incorporated collagen matrix, same procedure was performed by mixing elastin to previous collagen matrix in 4:1 ratio(collagen 80% elastin 20%). In comparison of the two dermal matrix in vitro tests, matrix contracture rate, strain, tensile strength, was measured and stiffness was calculated from comparative analysis. Results: In terms of matrix contracture, the elastin-incorperated added collagen dermis matrix showed 1.2 times more contraction compared to conventional collagen matrix. However, tensile strength showed 1.6 times and stiffness showed 1.6 times increase in elastin-incorporated matrix. Conclusion: Elastin incorperated collagen matrix manufactured by our team showed increased durability due to improvement in tensile strength and stiffness compared to previous collagen matrix($Integra^{(R)}$).

• 대한소아치과학회지
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• 제50권4호
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• pp.396-408
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• 2023

이 연구의 목적은 유구치를 재현한 인공치를 대상으로 인접면 복합레진 수복 시 매트릭스 시스템에 따른 인접면의 외형, 접촉면의 크기 및 수복 전과 후의 부피 차이를 비교해 보는 것이다. 네 가지 종류의 인공치에 Circumferential 매트릭스 시스템에 해당하는 Tofflemire Matrix System과 Sectional 매트릭스 시스템에 해당하는 Palodent V3 Sectional Matrix System, myJunior Kit를 이용하여 복합레진을 수복하고 3D 모델링 과정을 거쳐 분석되었다. Sectional 매트릭스 시스템을 사용한 경우에서 오목한 인접면 외형이 형성될 확률이 높았으며 더 큰 접촉 면적과 부피가 형성되었다. 이는 Sectional 매트릭스 시스템에 사용되는 매트릭스 밴드의 완전 연질(Dead soft) 특성에 의한 변형으로 인해 접촉점 주변으로 과량의 레진이 적용될 수 있기 때문이다. 게다가 Sectional 매트릭스 시스템에 포함된 고무 웨지가 매트릭스 밴드를 와동에 잘 적합 시키지 못할 가능성이 있다. 따라서 이번 연구의 결과를 바탕으로 유구치 인접면을 Sectional 매트릭스 시스템을 이용해 복합레진 수복하는 경우, 형태학적 관점을 고려한 신중한 사용이 요구된다.

• 대한치과보철학회지
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• 제38권3호
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• pp.366-374
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• 2000

FRC/ceromer system provides the clinician with a durable, flexible, and esthetic alternative to conventional porcelain fused to metal crowns. FRC is the matrix which is silica-coated and embedded in a resin matrix. The ceromer material which is a second generation indirect composite resin contains silanized, microhybrid inorganic fillers embedded in a light-curing organic matrix. FRC/ceromer restoration has a several advantages: better shock absorption, less wear of occluding teeth, translucency, color stability, bonding ability to dental hard tissues, and resiliency. It has versatility of use including inlay, onlay, single crown, and esthetic veneers. With adhesive technique, it can be used for single tooth replacement in forms of inlay adhesion bridge. In single tooth missing case, conventional PFM bridge has been used for esthetic restoration. However, this restoration has several disadvantages such as high cost, potential framework distortion during fabrication, and difficulty in repairing fractures. Inlay adhesion bridge with FRC/ceromer would be a good alternative treatment plan. This article describes a cases restored with Targis/Vectris inlay adhesion bridge. Tooth preparation guide, fabrication procedure, and cementation procedure of this system will be dealt. The strength/weakness of this restoration will be mentioned, also. If it has been used appropriately in carefully selected case, it can satisfy not only dentist's demand of sparing dental hard tissue but also patient's desire of seeking a esthetic restorations with a natural appearance.

• The Korean Journal of Ecology
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• 제21권6호
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• pp.791-797
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• 1998

An attempt to clarify the landscape structure of urban areas was carried out on Mt. Hwangryung located in the center of Pusan, southern Korea. By means of aerial photographs and field survey, a vegetation map including land-use pattern was made. Landscape structure was described by analyzing the vegetation map. Landscape element types were classified into secondary forest, introduced plantation, and other elements including urbanized area. almus firma and Pinus thunbergii communities, introduced plantation elements, formed matrix and some secondary forest elements and the other artificial plantations of small scale tended to distribute as small patches in such matrix. The number of patches per unit area in secondary forest elements was more than that in introduced plantation element. The result on patech size was vice versa. As the results of landscape ecological analyses, it was estimated that differentiation of patches recognized in community level would be related to artificial interference and those in sub-communities levels to natural process such as progression of succession. On the other hand, restoration plans in viewpoints of restoration and landscape ecology were suggested to improve ecological quality of Mt. hwangryung.

• 소성∙가공
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• 제3권4호
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• pp.427-439
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• 1994

The high temperature deformation behavior of $SiC_p/Al-Si$ composites and Al-Si matrix was studied by hot torsion test in a range of temperature from $270^{\circ}C$ to $520^{\circ}C$ and at strain rate range of $1.2{\times}10_{-3}~2.16{\times}10_{-1}/sec$. The hot restoration mechanisms for both matrix and composites were found to be dynamic recrystallization(DRX) from the investigation of flow curves and microstructural evolutions. The Si precipitates and SiC particles promoted DRX, and the peak strain$({\varepsilon}_p)$ of the composites was smaller than that of the matrix. Flow stresses of $SiC_p/Al-Si$ composites were found to be generally higher than the matrix, but the difference was quite small at higher temperature due to the decrease of capability of load transfer by SiC particles. With increasing temperature, failure strain of matrix and composites are inclined to increase, the increasing value of failure strain for the $SiC_p/Al-Si$ composites was small compared to that of matrix. The stress dependence of both materials on strain rate() and temperature(T) was examined by hyperbolic sine law, $\.{\varepsilon}=A_1[sinh({\alpha}{\cdot}{\sigma})]_n$exp(-Q/RT)

• Archives of Plastic Surgery
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• 제36권5호
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• pp.519-524
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• 2009

Purpose: This study was conducted to establish the most effective method of cell therapy by comparing and analyzing the level of wound healing after various cell delivery methods. Methods: Human mesenchymal stem cells were administered using 5 different methods on full thickness skin defects which were deliberately created on the back of 4 - week old mice using a 8 mm punch. Different modes of administration, cell suspension, local injection, collagen GAG matrix seeding, fibrin, and hydrogel mix methods were used. In each experiment group, $4{\times}105$ mesenchymal stem cells were administered according to 5 deferent methods, and were not for the corresponding control group. Results: The wound healing rate was fastest in the local injection group. The wound healing rate was relatively slow in the collagen matrix group, however, the number of blood vessels or VEGF increased most in this group. Conclusion: For rapid wound healing through wound contraction, it is advantageous to administer MSC by the local injection method. For the healing process of a wide area, such as a burn, the seeding of cells to collagen matrix is thought to be effective.

• 충청수학회지
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• 제25권2호
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• pp.367-377
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• 2012

The goal of the image restoration is to find a good approximation of the original image for the degraded image, the blurring matrix, and the statistics of the noise vector given. Fast truncated Lagrange (FTL) method has been proposed by G. Landi as a image restoration method for large-scale ill-conditioned BTTB linear systems([3]). We implemented FTL method for the image restoration problem with reflective boundary condition which gives better reconstructions of the unknown, the true image.

• Archives of Plastic Surgery
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• 제32권2호
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• pp.143-148
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• 2005

Chemotactic migration of bone forming cell, osteoblast, is an important event during bone formation, bone remodeling, and fracture healing. Migration of cells is mediated by adhesion receptors, such as integrins, that link the cell to extracellular matrix ligands, type I collagen, fibronectin, laminin and depend on interaction between integrin and extracellular ligand. Our study was designed to investigate the effect of extracellular matrix like fibronectin, laminin, type I collagen on migration of osteoblast. Migration distance and speed of MC3T3-E1 cell on extracellular matrix-coated glass were measured for 24 hours using 0.01% type I collagen, 0.01% fibronectin, 100 microliter/ml laminin. The migration distance and speed of MC3T3-E1 cell was compared using a video-microscopy system. To determine migration speed, cells were viewed with a 4 phase- contrast lens and video recorded. Images were captured using a color CCD camera and saved in 8-bit full-color mode. The migration distance on 0.01% type I collagen or 0.01% fibronectin was longer than that on $100{\mu}l/ml$ laminin-coated glass. The migration speed on fibronectin-coated glass was 68 micrometer/hour which was fastest. The migration speed on type I collagen-coated glass was similar with that on fibronectin-coated glass. The latter two migration speeds were faster than that on no-coated glass. On the other hand, the average migration speed on laminin-coated glass was 37micrometer/hour and not different from that of control group. In conclusion, the extracelluar matrix ligands such as type I collagen and fibronectin seem to play an important role in cell migration. The type I collagen or fibronectin coated scaffold is more effective for migration of osteoblast in tissue engineering process.

• 대한소아치과학회지
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• 제32권1호
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• pp.13-17
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• 2005

소아, 청소년 환자의 경우 성인에 비해 구치부 인접면 우식의 빈도가 높은 편이며, 그 수복 재료에 있어서 심미성이나 치질 삭제량 감소 등의 이유로 복합레진의 사용이 늘어나고 있는 추세에 있다. 복합레진을 이용한 구치부 인접면 수복에 있어서, 술자의 기호와 기술에 따라 여러 가지 매트릭스 밴드를 선택할 수 있으며, 이러한 매트릭스 밴드는 인접면 변연의 적합성과 이에 의한 미세 누출의 감소, 타액에 대한 방습 효과 및 마무리와 연마과정을 용이하게 하는 등 많은 임상적인 기능을 가진다. 본 증례에서는 복합레진과 교정용 밴드를 이용하여, 유치와 영구치 각각의 인접면 우식의 치료를 시행하였으며, 교정용 밴드를 이용한 2급 와동의 복합레진 충전에 있어서 기존의 매트릭스 밴드를 이용하는 경우에 비해 다음과 같은 장점이 있다고 판단하였다. 1. 우수한 변연 적합성에 의해, 치아 외형의 재현이 용이 하였으며 타액에 대한 방습 효과도 우수하였다. 2 복합레진의 충전이나 중합에 있어서, 교정용 밴드의 견고성에 의해 수복물의 변형이 작다고 판단되었다. 3. 간격 유지 장치 등의 이유로 교정용 밴드의 장착을 많이 시행하고 있는 소아치과 의사의 경우, 타과 전공 치과의사에 비해 비교적 교정용 밴드의 장착을 보다 효과적으로 할 수 있으며, 또한 적절하게 선택된 교정용 밴드는 위와 같은 장점들에 의해 수복 치료를 보다 용이하게 해주는 효과가 있다.

• Archives of Plastic Surgery
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• 제46권6호
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• pp.544-549
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• 2019

Background As the indications for postmastectomy radiotherapy expand, innovative solutions are required to reduce operative complications and reconstructive failure after prosthetic breast reconstruction. In this study, we investigated the effectiveness of acellular dermal matrix (ADM) inlay grafts in preventing postoperative wound dehiscence of irradiated breasts in the context of prosthetic breast reconstruction. Methods A retrospective analysis was conducted of 45 patients who received two-stage prosthetic reconstruction and radiotherapy following mastectomy. An ADM graft was placed beneath the incisional site during the second-stage operation in 19 patients using marionette sutures, whereas the control group did not receive the ADM reinforcement. Patient demographics and complications such as wound dehiscence, capsular contracture, peri-prosthetic infection, cellulitis, and seroma were compared between the two groups. Results During an average follow-up period of 37.1 months, wound dehiscence occurred significantly less often in the ADM-reinforced closure group (0%) than in the non-ADM group (23.1%) (P=0.032). There was no significant difference between the two groups in relation to other complications, such as capsular contracture, postoperative infection, or seroma. Conclusions The ADM inlay graft is a simple and easily reproducible technique for preventing incisional dehiscence in the setting of radiotherapy after prosthetic breast reconstruction. The ADM graft serves as a buttress to offload tension during healing and provides a mechanical barrier against pathogens. Application of this technique may serve to reduce complications in prosthetic breast reconstruction after radiotherapy.