• The Journal of Advanced Prosthodontics
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• 제11권1호
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• pp.7-15
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• 2019

PURPOSE. The aim of this study was to identify the effects of three aesthetic restorative materials on the wear between tooth and restoration by a pin-on-disk manner. MATERIALS AND METHODS. Six aesthetic restorative materials were used to prepare disk specimens for wear test, which were Lava Zirconia as zirconia group, Vintage MP and Cerabien ZR as veneering porcelain group, Gradia Direct microhybrid composite containing prepolymerized fillers, Filtek Z250 microhybrid composite containing zirconia glass and colloidal silica particles, and Filtek Z350 nanocomposite as composite resin group. Vertical loss of the worn cusp, change of the surface roughness of the restoration materials, and the surface topography were investigated after wear test under 9.8-N contact load. RESULTS. The porcelain groups (Vintage MP and Cerabien ZR) caused the largest vertical loss of teeth when compared with those of the composite resin and zirconia groups, and Filtek Z250 microhybrid composite results in the second-largest vertical loss of teeth. The surface of Filtek Z350 nanocomposite was deeply worn out, but visible wear on the surface of the zirconia and Gradia Direct microhybrid composite was not observed. When the zirconia surface was roughened by sand-blasting, vertical loss of teeth considerably increased when compared with that in the case of fine polished zirconia. CONCLUSION. It was identified that microhybrid composite resin containing a prepolymerized filler and zirconia with reduced surface roughness by polishing were the most desirable restorative materials among the tested materials to prevent the two-body wear between aesthetic restorative material and tooth.

• Composites Research
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• 제36권2호
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• pp.126-131
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• 2023

기존의 상용 플라스틱으로 인한 환경 오염에 대한 우려가 높아지면서 대체 재료로서 생분해성 고분자에 대한 연구가 주목을 받고 있다. 본 연구는 생분해성 열가소성 수지인 폴리 젖산에 유기 핵제의 도입으로 물성 강화 및 100% 생분해 가능한 나노복합재 개발을 목표로 한다. 그에 따라 무기 핵제의 대체재로 친환경 소재인 셀룰로오스 나노섬유를 채택하였다. 폴리 젖산 내 셀룰로오스 나노섬유의 균일한 분산을 위해 동결 건조 방식으로 나노화된 섬유 형상을 유지시켰으며, 이축압출기로 1차 교반을 진행하고, 사출 성형을 통해 이중 교반된 물성 시험용 시편을 제작하였다. 보강된 결정성을 확인하기 위해 시차주사 열량분석법을 사용하였고 1 wt%의 셀룰로오스 나노섬유가 보강재 및 핵제로서 작용하여 냉결정화온도가 약 14℃ 가량 감소하며, 결정화되는 정도 또한 증가한 것을 확인하였다. 본 연구는 기존 생분해성 고분자의 무기 핵제를 유기 나노소재로 대체함으로써 100% 생분해 가능한 친환경 나노복합재 개발하여 강화된 물성의 플라스틱 소재 개발을 위한 친환경적 대안을 제시한다.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.179-179
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• 2006

PLGA/HA composite scaffold fabricated by GF/PL method showed enhanced mechanical property, hydrophilicity and osteoconductivity compared with the SC/PL scaffolds, and this enhancement was most likely due to a higher extent of exposure of HA particles to the scaffold surface. The biodegradable polymer/bioceramic composite scaffolds fabricated by the GF/PL method could enhance bone regeneration efficacy for the treatment of bone defects compared with conventional composite scaffolds.

• KSBB Journal
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• 제5권4호
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• pp.377-382
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• 1990

The characteristics controlled drug release have been studied for biodegradable polymer matrix. Polymer matrix was prepared from glycerine, prednisolone and dextran. Mathematical analysis of the data showed that the release behavior actually conformed to the Higuchi's diffusion controlled model. The release time was increased as drug loading doses increased, whereas decreased as glycerine concentration increased. The release rate did not change by varying molecular weight of dextran.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 가을 학술발표회 논문집
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• pp.209-210
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• 2003

The durability and anti-microbial stability of plastics, which have been thought to be favorable characteristics, cause ecoloical problems due to non-degradation after disposal. For a possible solution of these ecological and environmental problems, the biodegradable polymers. especially aliphatic polyesters, have been widely investigated. Poly(tetramethylene succinate)(PTMS) is one of the most promising biodegradable polyesters. (omitted)

• KSBB Journal
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• 제9권4호
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• pp.412-417
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• 1994

The biodegradable characteristics of starch-filled polyethylene film by fungi were investigated. Aspergillus niger showed the highest cell growth among five species of fungi used in the experiment. Higher starch content gave the higher growth rate of A. niger; however, the kind of film or cutting direction did not give any effects on the cell growth. The use of vinyl trimethoxysilane for the stronger binding of starch and polyethylene did not inhibit the cell growth. When the starch content was higher than 10%, the elongation of the film decreased significantly after the growth of microorganism in the case of transverse direction samples.

• 월간포장계
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• 통권130호
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• pp.109-117
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• 2004

• 월간포장계
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• 통권85호
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• pp.154-161
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• 2000

• 한국동물위생학회지
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• 제43권3호
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• pp.129-137
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• 2020

In this study, we applied biodegradable drug delivery carries (BDDC) for food-and-mouth (FMD) vaccination. After FMD vaccination using BDDC, we estimated the percentage inhibition (PI) of antibody, decomposed patterns, and histopathologic features of BDDC. PI of antibody was higher than 50 at two weeks after injection and sustained positive PI until 10 weeks after injection. BBDC injection group showed significantly an increased pattern of blood monocyte at two and three weeks after injection. According to the Micro CT, micro-cracks were observed at two weeks after injection and the morphology of BDDC was lost at four weeks after injection. For histopathological examination, acute inflammation with neutrophil infiltration and micro-metallic residues were observed around BDDC until four weeks after injection and inflammatory responses gradually decreased at 10 weeks. Based on our experiment, BDDC is considered as an alternative way to vaccine injection for veterinary applications. Our study can be used as basic data for the drug delivery system using biodegradable metals in the future.

• 한국입자에어로졸학회지
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• 제13권3호
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• pp.111-118
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• 2017

전기수력학 (Electrohydrodynamic, EHD) 프린팅 기술은 전기장을 이용하여 일반 프린팅 기술보다 더 작은 크기의 액적을 분사하고 패터닝할 수 있는 장점을 갖고 있다. EHD 프린팅은 일반적으로 인쇄 노즐이나 기판을 X-Y 방향으로 움직여 패턴을 제작하는 방식으로 사용되어 왔으나 본 연구에서는 다중전극 어레이 (Multielectrode array, MEA)를 이용하여 원하는 기판위에 2차원의 패터닝이 가능함을 연구하였다. 특히, 약물전달장치 등의 바이오메디칼 디바이스로의 응용이 가능한 생분해성 고분자와 염료를 혼합한 잉크의 EHD 프린팅을 시도하였으며 노즐이나 기판의 움직임 없이 안정적으로 분사할 수 있는 2차원 범위에 대한 연구를 통해 최소 약 $6{\mu}m$ 크기를 갖는 패턴을 노즐 위치로부터 수평방향으로 약 1 mm 범위까지 안정적 패터닝이 가능함을 확인하였다. 또한, MEA 전극 간의 거리에 의한 패턴 조밀도의 한계를 극복하기 위해 MEA와 인쇄가 이루어지는 기판과의 상대적 이동을 통해 더 조밀한 패터닝이 가능함을 보여주었다.