• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권4호
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• pp.363-367
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• 2011

Genioplasy with osteotomy is a flexible and useful procedure. However, osteotomy can cause different types of morbidity. Chin augmentation with porous polyethylene ($Medpor^{(R)}$) has become popular in the recent years. Porous polyethylene ($Medpor^{(R)}$) is an excellent biomaterial for reconstructing facial deformities. $Medpor^{(R)}$ has a porous architecture, which prevents capsule formation and decreases the degree of foreign-body reaction. In addition, it can be easily cut with scissors and molded, and it also maintains its shape. We report here on a satisfactory case of chin augmentation with using porous polyethylene ($Medpor^{(R)}$).

• 한국세라믹학회지
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• 제55권1호
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• pp.85-89
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• 2018

This work reported the preparation and evaluation of a freshness-keeping film prepared by composite of a porous ceramic material such as vermiculite and polyethylene polymer. The ceramic material was pretreated physically and chemically to control the specific surface areas and particle size. A high content master-batch was prepared using the pretreated vermiculite. The master-batch, which contained 30% ceramic material, was mixed with a polymer material to prepare a film containing 3% vermiculite. The oxygen permeability and various physicochemical properties were evaluated for the prepared films. Compared to plain polyethylene film, the vermiculite loaded polyethylene film has a freshness maintenance property, indicating the creation of an improved film.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제35권3호
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• pp.184-188
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• 2013

Post-traumatic enophthalmos is a relatively common problem following orbitozygomatic fractures. Bony-volume expansion and soft tissue atrophy are considered the main etiological causes of this condition. Enophthalmos is corrected mostly through reducing the enlarged orbit volume. Autogenous graft and various alloplastic materials are used for this purpose. Porous polyethylene is highly biocompatible, durable, and remarkably stable. Also, the titanium plate embedded in a porous polyethylene sheet provides radiographic visibility and increased sheet strength and contour retention. We present experiences of titanium reinforced porous polyethylene for correction of the traumatic enophthalmos with literature review.

• Archives of Plastic Surgery
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• 제37권4호
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• pp.400-408
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• 2010

Purpose: Complete septal extension grafts have been widely used in rhinoplasty for effective projection of the short retruded columella in Asian patients. Autologous septal cartilages and porous high-density polyethylene sheets are frequently used as septal extension grafts. This study was conducted to compare the postoperative results of porous polyethylene sheets and septal cartilages used for correction of unilateral cleft lip nasal deformities by using photogrammetric analysis. Methods: This study investigated a total of 49 patients with cleft lip nasal deformities who underwent corrective surgery, and were followed up for at least 6 months. Septal cartilages were used in 39 patients, and porous polyethylene sheets were used in 10 patients. In all patients, through the open rhinoplasty, complete septal extension grafts were sutured to the caudal margin of the septal cartilage, and the alar cartilage was sutured with suspension. The cleft side alar cartilage was overcorrected by approximately 3 - 5 mm. Postoperative outcomes were evaluated by using photogrammetric analysis. Five indices and 4 angles were measured on their photographs taken before and after the surgery. In patients with unilateral cleft lip nasal deformities, symmetry was also evaluated by means of columellar length index. Results: The postoperative values obtained in photogrammetric analysis showed improvements in comparison with the preoperative ones. The polyethylene group produced more improved outcomes than the septal cartilage group but also resulted in more complications at the same time. Conclusion: The results of this study indicates that complete septal extension grafts are efficient for the correction of unilateral cleft lip nasal deformities. However, since postoperative complications occur more frequently in the polyethylene group than in the septal cartilage group, caution is advised in using porous high-density polyethylene sheets in patients with cleft lip nasal deformities.

• 청정기술
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• 제4권2호
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• pp.32-40
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• 1998

Polypropylene(PP)과 polyethylene(PE) 분체를 혼합하여 공기정화용 여과재로 사용하기 위한 기공성 고분자 소재를 압출 소결법으로 제조하였다. PP와 PE로 구성된 기공성 고분자 소재는 녹는점이 낮은 PE가 용융되어 PP를 결합시킨 구조임을 주사전자현미경(scanning electron microscope) 분석으로 관찰할 수 있었으며, 고분자 소재의 압출 소결시 압출기 다이 헤드의 온도, 압출 속도, PE의 용융지수 및 첨가량 변화 등에 따른 기공성 고분자 소재의 기계적물성과 여과특성 변화를 시험하였다. 일정한 압출기 헤드 다이 온도와 압출 속도하에서 압출 소결법으로 제조된 기공성 고분자 소재의 여과효율이 PE의 첨가량과는 비례 관계를 나타내었으나 PE의 용융지수에는 반비례 관계를 나타냄을 관찰할 수 있었다. 압출 소결법으로 제조된 기공성 고분자 소재의 여과특성을 시험한 결과, PP와 PE로 구성된 기공성 고분자 소재가 공기정화용 여과재로 적용될 수 있음을 확인할 수 있었다.

• Macromolecular Research
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• 제14권4호
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• pp.430-437
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• 2006

The ultra-drawing process of an ultra high molecular weight polyethylene (UHMWPE) gel film was examined by incorporating linear low-density polyethylene (LLDPE) and $BaTiO_3$ nanoparticles. The effects of LLDPE and the draw ratios on the morphological development and mechanical properties of the nanocomposite membrane systems were investigated. By incorporating $BaTiO_3$ nanoparticles in the UHMWPE/LLDPE blend systems, the ultra-drawing process provided a highly extended, fibril structure of UHMWPE chains to form highly porous, composite membranes with well-dispersed nanoparticles. The ultra-drawing process of UHMWPE/LLDPE dry-gel films desirably dispersed the highly loaded $BaTiO_3$ nanoparticles in the porous membrane, which could be used to form multi-layered structures for electronic applications in various embedded, printed circuit board (PCB) systems.

• Journal of Periodontal and Implant Science
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• 제50권2호
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• pp.106-120
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• 2020

Purpose: A new form of porous polyethylene, characterized by higher porosity and pore interconnectivity, was developed for use as a tissue-integrated implant. This study evaluated the effectiveness of porous polyethylene blocks used as an onlay bone graft in rabbit mandible in terms of tissue reaction, bone ingrowth, fibrovascularization, and graft-bone interfacial integrity. Methods: Twelve New Zealand white rabbits were randomized into 3 treatment groups according to the study period (4, 12, or 24 weeks). Cylindrical specimens measuring 5 mm in diameter and 4.5 mm in thickness were placed directly on the body of the mandible without bone bed decortication, fixed in place with a titanium screw, and covered with a collagen membrane. Histologic and histomorphometric analyses were done using hematoxylin and eosin-stained bone slices. Interfacial shear strength was tested to quantify graft-bone interfacial integrity. Results: The porous polyethylene graft was observed to integrate with the mandibular bone and exhibited tissue-bridge connections. At all postoperative time points, it was noted that the host tissues had grown deep into the pores of the porous polyethylene in the direction from the interface to the center of the graft. Both fibrovascular tissue and bone were found within the pores, but most bone ingrowth was observed at the graft-mandibular bone interface. Bone ingrowth depth and interfacial shear strength were in the range of 2.76-3.89 mm and 1.11-1.43 MPa, respectively. No significant differences among post-implantation time points were found for tissue ingrowth percentage and interfacial shear strength (P>0.05). Conclusions: Within the limits of the study, the present study revealed that the new porous polyethylene did not provoke any adverse systemic reactions. The material promoted fibrovascularization and displayed osteoconductive and osteogenic properties within and outside the contact interface. Stable interfacial integration between the graft and bone also took place.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제44권3호
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• pp.128-135
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• 2018

Objectives: The role of alloplastic materials in maxillofacial reconstruction is still controversial. Determining the utility of porous, high-density, polyethylene implants as a highly stable and flexible, porous alloplast, with properties such as rapid vascularization and tissue ingrowth, is crucial in cases of maxillofacial deformities and aesthetic surgery. Materials and Methods: Thirty high-density porous polyethylene implants were implanted in 16 patients that had been referred to a private office over a three-year period. These implants were used for correcting congenital deformities, posttraumatic defects and improving the aesthetic in nasal, paranasal, malar, chin, mandibular angle, body and orbital areas. Results: The outcomes of the cases in this study showed good aesthetic and functional results. The majority of patients had no signs of discomfort, rejection or exposure. Two implants suffered complications: a complicated malar implant was managed by antibiotic therapy, and an infected mandibular angle implant was removed despite antibiotic therapy. Conclusion: Based on the results, the Medpor implant seems to be an excellent biomaterial for correcting various facial deformities. Advantages include its versatility and relatively ideal pore size that allows for excellent soft tissue ingrowth and coverage. It is strong, flexible and easy to shape.

• 펄프종이기술
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• 제39권2호
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• pp.9-16
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• 2007

Biological treatment using the activated sludge method and biofilm process has been developed for paper wastewater treatment. It is known that a water treatment using biofilm process has a high efficiency be-cause a great deal of microorganism could adhere to media. It is also known that various plastics such as polyurethane and polyethylene have been used as the media. In this study polyethylene was used as a media and rice straw an additive agent to improve porous and hydrophilic properties of the media for waste water treatment. Porosity and hydrophilic characteristics of polyethylene was increased as rice straw was added to polyethylene. Paper wastewater was then treated with newly developed environment materials. Rice straw showed excellent results in waste water treatment in various media. This environmentally friendly material prepared by polyethylene and rice straw could show similar results to those of a commercial porous polyurethane foam in wastewater treatment.

• Macromolecular Research
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• 제15권3호
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• pp.256-262
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• 2007

The purpose of this study was to determine the effect of surface modification on the fibrovascular ingrowth into porous polyethylene (PE) spheres ($Medpor^{(R)}$), which are used as an anophthalmic socket implant material. To make the inert, hydrophobic PE surface hydrophilic, nonporous PE film and porous PE spheres were subjected to plasma treatment and in situ acrylic acid (AA) grafting followed by the immobilization of arginine-glycine-aspartic acid (RGD) peptide. The surface-modified PE was evaluated by performing surface analyses and tested for fibroblast adhesion and proliferation in vitro. In addition, the porous PE implants were inserted for up to 3 weeks in the abdominal area of rabbits and, after their retrieval, the level of fibrovascular ingrowth within the implants was assessed in vivo. As compared to the unmodified PE control, a significant increase in the hydrophilicity of both the AA-grafted (PE-g-PAA) and RGD-immobilized PE (PE-g-RGD) was observed by the measurement of the water contact angle. The cell adhesion at 72 h was most notable in the PE-g-RGD, followed by the PE-g-PAA and PE control. There was no significant difference between the two modified surfaces. When the cross-sectional area of tissue ingrowth in vivo was evaluated, the area of fibrovascularization was the largest with PE-g-RGD. The results of immunostaining of CD31, which is indicative of the degree of vascularization, showed that the RGD-immobilized surface could elicit more widespread fibrovascularization within the porous PE implants. This work demonstrates that the present surface modifications, viz. hydrophilic AA grafting and RGD peptide immobilization, can be very effective in inducing fibrovascular ingrowth into porous PE implants.