• Journal of Periodontal and Implant Science
• /
• v.26 no.1
• /
• pp.133-142
• /
• 1996

Ten intrabony defects in 10 patients were treated by flap surgery including root surface debridement and placement of an expanded polytetrafluoroethylene(ePTFE) membrane. The membranes were removed after 4-6 weeks. This study was performed to examine the retrived ePTFE membrane by scanning electron microscopy(SEM) for bacterial contamination and adherent connective tissue elements, and to compare it with clinical conditions. The cervical portion of the membrane, which in most cases had become partially exposed to the oral cavity, had a bacterial deposit. Small bacterial colonies and a scatter of single cells in some instances extended into the apical portion of the membrane. Fibroblast-like cells, erythrocytes and fibrous structures were seen in the apical portion of the membrane. Outer surface of membrane tends to more bacterial contamination than inner surface(p<0.01), and upper portions more than lower portions(P<0.01). Comparison of ultrastructural findings and clinical conditions revealed that extent of bacterial contamination of the membrane correlated with gingival inflammation and extent of membrane exposure, but it was not significant statistically. The results suggested that gingival inflammation and membrane exposure affect periodontal regeneration by the use of ePTFE membrane.

• Journal of Periodontal and Implant Science
• /
• v.26 no.3
• /
• pp.567-577
• /
• 1996

탈회냉동건조골 (DFDBA)과 ePTFE막을 사용한 경우와 ePTFE만을 사용한 경우의 조직유도 재생술의 효과를 관찰하였다 . 12명의 환자에서 12개의 골내낭결손부(한 환자당 하나의 결손부)를 통상적인 치주수술 시행한 경우를 대조군(GFS)으로 , 12명의 환자에서 12개의 결손부는 ePTFE(GTR)막 만으로 , 또 다른 환자의 12개결손부는 ePTFE+DFDBA로 시행하였다. 창상안정과 감염방지를 강조한 술후계획이 사용되었다. 술후 6개월째 임상적 치유상태를 평가 하였다. 대조군에서 치주낭깊이, 부착수준, 탐침골깊이, 치은퇴축의 각각의 평균치는 $3.4{\pm}1.3mm$, $2.0{\pm}1.2mm$, $1.3{\pm}2.0mm$, $-1.7{\pm}0.8mm$, GTR 군에서는 $4.3{\pm}l.3mm$, $3.1{\pm}1.5mm$, $4.2{\pm}2.2mm$, $-11{\pm}1.4mm$ 그리고 GTR+DFDBA 군에서는 $3.4{\pm}2.1mm$, $2.4{\pm}1.9mm$, $2.6{\pm}1.6mm$, $-1.2{\pm}1.7mm$를 보였다. 대조군과 GTR+DFDBA 군의 술전 평균 치주낭깊이는 각각 $6.9{\pm}1.1$, $7.4{\pm}1.2$, $7.0{\pm}2.0mm$였다. GTR, GTR+DFDBA군에서는 뚜렸한 치주낭감소와 부착획득을 보였다(P<0.01). GTR, GTR+DFDBA 에서는 대조군에 비해 탐침골수준의 뚜렷한 향상을 보였으나(P<0.001), GTR 과 GTR+DFDBA 사이에는 뚜렷한 차이가 없었다. 이 실험결과로 골내낭 결손부에서 GTR과 GTR+DFDBA의 사용은 골형성을 제외한 임상결과 에서 대조군과 유사한 결과를 보였다.

• Journal of Periodontal and Implant Science
• /
• v.36 no.2
• /
• pp.289-303
• /
• 2006

This study was performed to evaluate the effect of bone graft materials including demineralized freeze-dried bone, freeze-dried bone, deproteinized bovine bone on space-making capacity and bone formation in guided bone regeneration with titanium reinforced ePTFE membrane(TR-ePTFE). Adult male rabbits(mean BW 2kg) were used in this study. Intramarrow penetration defects were surgically created with round bur on calvaria of rabbits. TR-ePTFE membrane was adapted to calvarial defect and bone graft materials were placed. Animals were sacrificed at 2, 8, 12 weeks after surgery. Non-decalcified specimens were processed for histologic analysis and prepared with Villaneuva bone stain. The results of this study were as follows: 1. TR-ePTFE membrane was biocompatible and capable of maintaining the space-making. 2. Tissue integration was not good at TR-ePTFE membrane. Fixation was not enough. so, wound stabilization was not good. 3. In animals using deproteinized bovine bone, demineralized freeze-dried bone, bone formation was little. 4. In animals using freeze-dried bone, bone formation was better. Within the above results, bone formation may be inhibited when wound stabilizafion was not good.

• Membrane Journal
• /
• v.33 no.4
• /
• pp.201-210
• /
• 2023

Dust filter membranes play a crucial role in human life and various industries, as they contribute to several important aspects of human health, safety, and environmental protection. This study presents the development of a polysulfone@polyphenylene sulfide/polytetrafluoroethylene (PSf@PPS/ePTFE) composite dust filter membrane with excellent thermal stability and adhesion properties for high-temperature conditions. FT-IR analysis confirms successful impregnation of PSf adhesive onto PPS fabric and interaction with ePTFE support. FE-SEM images reveal improved fiber interconnection and adhesion with increased PSf concentration. PSf@PPS/ePTFE-5 exhibits the most suitable porous structure. The composite membrane demonstrates exceptional thermal stability up to 400℃. Peel resistance tests show sufficient adhesion for dust filtration, ensuring reliable performance under tough, high-temperature conditions without compromising air permeability. This membrane offers promising potential for industrial applications. Further optimizations and applications can be explored.

• Journal of Periodontal and Implant Science
• /
• v.25 no.2
• /
• pp.301-320
• /
• 1995

The purpose of this study was to evaluate a new biodegradable membrane - atelocollagen as a guided tissue regeneration barrier on the dehiscence defects adjacent to the dental implants. 3 beagle dogs were selected for this study and all the mandibular premolars($P_1,P_2,P_3&P_4$) were extracted. Twelve weeks after the extraction, the edentulous ridges were formed to be placed the titanium plasma-sprayed IMZ implants. Four implant osteotomies were performed on each side of the mandible. The osteotomies were placed facially in the edentulous ridges to approximate an actual dehiscence defect as closely as possible, The standardized dehiscence defects were created 3 mm in width and 4 mm in height by osteotomy. A total 24 implants were placed. e-PTFE, ateloco11agen and $Collatape^{(R)}$ were placed to cover the defects and the one defect served as a control, not covered any membrane. By random selection, three dogs were sacrificed at 2 weeks, 4weeks and 8 weeks after fixation with 3% glutaraldehyde. A week before sacrificing, 8-week dog was infused intravenously with oxy-tetracycline 30mg/kg. The left mandibular blocks were used for full decalcified histologic preparation and the right mandibular blocks were selected for undeca1cified preparation, At 2 weeks, the regenerated bone of e-PTFE and atelocollagen groups appeared to be more dense than other groups and the percentage of bone defect fill was highest for e-PTFE and follwed by ateloco1lagen group. However, the $Collatape^{(R)}$ and control groups showed a little new bone formation. $Collatape^{(R)}$ was almost degraded within 2 weeks. At 4 weeks, the regenerated new bone were much greater and denser than at 2 weeks for e-PTFE and ateloco11agen group. Although a part of atelocollagen bagan to be degraded at the margin and surrounded by foreign body giant cells related to foreign body reaction, it was generally intact and the regenerated new bone was shown much more than at 2 weeks. The amount of new bone in $Collatape^{(R)}$ and control groups at 4 weeks were similar to that of 2 weeks group. At 8 weeks, the regenerated bone was matured and observed along the implant fixture. Direct new bone formation and calcium deposits beneath the e-PTFE were observed. No further bone growth was seen in the $Collatape^{(R)}$ and control groups. In reflected fluoromicrcocopic observation, the osteogenic activity was pronounced between e-PTFE membrane and the old bone. High osteogenic activity was also observed in atelocol1agen group. This study suggested that the ateloco11agen as well as e-PTFE could be used for guided tissue regeneration on dehiscence defects adjacent to the dental implants. But the $Collatape^{(R)}$ was completely resorbed within 2 weeks and was not a suitable membrane for guided bone regeneration.

• Journal of Power System Engineering
• /
• v.14 no.4
• /
• pp.50-55
• /
• 2010

In order to investigate tribological effects of nano copper particles impregnated(CuN) on surface polytetrafluoroethylene(PTFE) on sealing wear and an experimental study was carried out to determine the wear behavior of copper nano-particles impregnation two kind thickness in super critical $CO_2$ liquid. Experimental results showed that the friction coefficients of CuN PTFE at the low sliding speed(0.44m/s) and the oil temperature ($60^{\circ}C$) were higher than that of virgin PTFE. And a thin nano copper particles impreganated thickness was formed on the surface in the PTFE and the specimen with this treatment has much better friction properties than the original one. Fortunately, at the high load(80 N) and the oil temperature, the friction coefficient of CuN PTFE was lower than that of virgin PTFE. This evidenced the load carrying capacity of CuN PTFE was much better than that of virgin PTFE under the high load condition(80 N) specially. Therefore, it can be concluded that the friction coefficient variation of CuN PTFE is very small but its wear rate decreases greatly with increase in sliding speed.

• Polymer(Korea)
• /
• v.36 no.3
• /
• pp.326-331
• /
• 2012

In this study, expanded poly(tetrafluoro ethylene) (ePTFE) graft was modified to be used as a hemodialysis vascular access. Biodegradable poly(D,L-lactide-$co$-glycolide) (PLGA) was coated onto the inner surface of ePTFE graft with paclitaxel, which is often used as an anti-cancer agent and for reducing neointimal hyperplasia. Surface characterization before and after PLGA coating was carried out by SEM and ATR-FTIR. Porous sturcture of ePTFE was maintained after coating of PLGA solution. The amounts of coated PLGA and paclitaxel determined by ATR-FTIR and HPLC were 1.96 and 0.263 mg/$cm^2$, respectively. Young's modulus was decreased and tensile strength was increased by PLGA coating. Released paclitaxel as a function of incubation time was monitored by HPLC. Approximately 35% of coated paclitaxel was released steadily for 4 weeks with the biodegradation of PLGA. From these results, it is expected that the effect of paclitaxel on reducing neointimal hyperplasia and stenosis is maintained for a long time.

• Journal of Periodontal and Implant Science
• /
• v.26 no.4
• /
• pp.967-987
• /
• 1996

The present study was to evaluate the healing patterns of guided tissue regeneration( GTR) using resorbable $Vicryl^{(R)}$(polyglactin 910) mesh and nonresorbable expanded polytetrafluoroethylene(ePTFE) membrane with or without bone grafting using autogeneous bone and demineralized freeze-dried bone allograft(DFDBA) in the grade II furcation defects. Mucoperiosteal flaps were reflected buccally in the mandibular 2nd, 3rd and 4th premolar areas and furcation defects were created surgically by removing $5{\times}6mm$ alveolar bone in 4 dogs. Root surfaces were thoroughly debrided of periodontal ligament and cementum, and notches were placed on root surface at the most apical bone level. In the right and left mandibular quadrant, each tooth was received $Vicryl^{(R)}$ mesh(ACE Surgical Supply Co., USA) only, $Vicryl^{(R)}$ mesh with DFDBA, $Vicryl^{(R)}$ mesh with autogeneous bone grafts, ePTFE membrane($Core-tex^{(R)}$ membrane, W.L. Gore & Associates Inc., USA) only, ePTFE membrane with DFDBA or ePTFE membrane with autogeneous bone grafts. For the fluorescent microscopic examination, fluorescent agents were injected at 2, 4 and 8 weeks after surgery. Four weeks after surgery, 2 dogs were sacrificed and ePTFE membranes were removed from remaining 2 dogs, which were sacrificed at 12 weeks after surgery. Undecalcified tissues were embedded in methylmethacrylate and $10{\mu}m$ thick sections were cut in a buccolingual direction. These sections were stained with hematoxylin-eosin stain and Masson's trichrome stain, and evaluated by descriptive histology and linear measurements. The results were as follows : 1) $Vicryl^{(R)}$ mesh group showed less connective tissue attachment than ePTFE membrane group. 2) The combination of GTR using $Vicryl^{(R)}$ mesh and osseous grafts resulted in new attachment and new bone formation more than GTR using $Vicryl^{(R)}$ mesh only. 3) GTR using ePTFE membrane, with or without osseous grafts, enhanced periodontal regeneration. 4) Root resorption and dentoalveolar ankylosis were observed in the areas treated with the combination of GTR and DFDBA. It was suggested that the effect of adjunctive bone grafting in GTR procedure depends on the materials and the physical properties of barrier membranes. $Vicryl^{(R)}$ mesh performed a barrier function and the use of adjunctive bone grafting may enhance the periodontal regeneration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.156-156
• /
• 2009

전자기기의 Slim화에 따라 부품 일장용 Board 기판의 두께도 날로 감소해지고 있다. 이와는 정 반대로 기판의 층수는 더 늘어나고 있다. 이에 따라 기판의 구성요소인 절연재의 두께도 감소하고 있다. 전자기기는 각각의 Module이 저항을 가지는데 이를 matching하기 위해서 각 module이나 package가 가지는 저항값을 상호 비슷하게 맞춘다. 하지만, 기판의 절연재의 두께 감소는 이러한 저항값이 낮아지게 한다. 이렇게 낮아진 저항값을 높이기 위해서는 전도체의 폭을 줄여야 한다. 하지만, 이렇게 전도체의 폭을 줄이는 것은 기판 제작 비용의 상승 및 제작 물가에 이르게 할 수 있다. 이를 해결하기 위해서는 절연재의 유전율을 낮추는 것이 가장 효과적이다. 본 연구에서는 PCB 기판의 유전율을 낮추기 위해 Liquid Crystalline Polymer(LCP)에 PTFE powder를 넣어 기판 재료의 가능성을 조사하였다. 유전율은 PTFE의 첨가량이 증가함에 따라 감소하여 40wt% 첨가할 경우 유전율이 2.4 정도로 낮아졌다. 이에 반해 열팽창계수는 증가가 크지 않고 peel strength는 감소함을 알 수 있었다.

• Journal of Periodontal and Implant Science
• /
• v.34 no.1
• /
• pp.149-162
• /
• 2004

This study was performed to evaluate the effect of freeze-dried bone graft on space-making capacity and bone formation in the procedure of guided bone regeneration with titanium reinforced ePTFE membrane. After decortication in the calvaria, GBR procedure was performed on 8 rabbits with titanium reinforced ePTFE membrane filled with human FDBA(Rocky Mountain Tissue Bank,Aurora Co., USA). Decortication was performed to induce the effect of bone forming factor from bone marrow. The animals were sacrificed at 2 weeks, 4 weeks, 8 weeks and 12 weeks after the surgery. Non-decalcified specimens were processed for histologic analysis. πle results of this study were as follows: 1. Titanium reinforced-ePTFE membrane was biocompatable and capable of maintaining the space-making. 2. FDBA particle was surrounded with connective tissues but there was no evidence on new bone formation. 3. FDBA particle resorbed continuously but it remained until 12weeks after the surgery. Within the above results, TR-ePTFE membrane could be used effectively for Guided bone regeneration but It was assumed that FDBA does not appear to contribute to bone formation.