• Journal of Periodontal and Implant Science
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• 제27권3호
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• pp.479-493
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• 1997

There are various treatment methods including barrier membranes in attaining periodontal regeneration and regaining the function of destructed periodontal tissues due to periodontal disease. Barrier membranes consist of non-Resorbable and resorbable types such as Dura mater and $Guidor^{(R)}$ used in the treatment of intrabony defects and classII furcation defects have been shown to be effectively increased the amount of new bone and cementum.In our study we used premolars with class III furcation defects created by removing the bone 4mm apically from CEJ in adult dogs and placed resorbable membrane Dura mater and $Guidor^{(R)}$ for the test group and flap operation was carried out for the control groups. The effect of membrane on junctional epithelium, alveloar bone, cementum, and gingival connective tisssue in the regeneration and healing potential of periodontal tissues was evaluated and healing results were evaluated histologically and histometrically 8 weeks following the surgical procedure. 1. In the clinical observation, there was no exposure of furcation defects in the control group, whereas slight membrane exposure was noted in the test group. 2. New bone was formed up to the level of the notch in the control group, whereas in the test group new bone formation was observed above the level of the notch. 3. New cementum was formed in both groups of the experiment. 4. The connective tissue observed between the new cementum and new bone in the test group were functionally orientated, compared to the irregular formation of connective tissues found in the control group. 5. Root resorption or ankylosis was not observed in any of the groups 6. The mean and median of the control group were 4.31% and 2.23% and for the Dura mater group were 27.85% and 15.57% respectively. There was no significant difference between Dura mater and the control group. 7. The mean and median of the control group were 4.31% and 2.23% and for the $Guidor^{(R)}$ group were 37.27% and 37.19% respectively. There was a significant difference in these two groups(P$Guidor^{(R)}$ were 37.27% and 37.19%. There was no significant difference between the two test groups. Thus, by using Dura mater and Guidor in classIII furcation defects, the predictable amount of periodontal ligament and alveolar bone regeneration may result.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권4호
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• pp.181-187
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• 2014

Objectives: The purpose of this preliminary study is to evaluate the effectiveness of a customized, three-dimensional, preformed titanium mesh as a barrier membrane for peri-implant alveolar bone regeneration. Materials and Methods: Ten patients were recruited for this study. At the time of implant placement, all patients had fenestration or a dehiscence defect around the implant fixture. A mixture of particulate intraoral autologous bone and freeze-dried bone allograft was applied to the defect in a 1 : 1 volume ratio and covered by the preformed titanium mesh. A core biopsy specimen was taken from the regenerated bone four months postoperatively. Patients were followed for 12 months after the definitive prosthesis was placed. Results: Satisfactory bone regeneration with limited fibrous tissue was detected beneath the preformed titanium mesh. Histologic findings revealed that newly formed bones were well-incorporated into the allografts and connective tissue. New growth was composed of approximately 80% vital bone, 5% fibrous marrow tissue, and 15% remaining allograft. All implants were functional without any significant complications. Conclusion: The use of preformed titanium mesh may support bone regeneration by maintaining space for new bone growth through its macro-pores. This preliminary study presents the efficacy of a preformed titanium mesh as a ready-to-use barrier membrane around peri-implant alveolar bone defect. This preformed mesh is also convenient to apply and to remove.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권1호
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• pp.85-92
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• 2005

Reconstruction of defect in the anterior part of the maxilla to enable implant placement or prothesis is a complicated treatment due to the anatomical position and lack of soft tissues. Two cases are presented in which autogenous iliac PMCB(particulate marrow and cancellous bone) with titanium mesh were used for premaxilla reconstruction and alveolar bone repair of the anterior maxillas prior to denture and implants fixation respectively. Cancellous bone from the anterior iliac crest was compressed and placed against a titanium mesh fixed to the bone of palate in a patient with severe defect of the anterior maxilla. There were no problem in the healing, and the anterior maxillas of two patients had increased height and width during the initial healing and remodeling. The clinical reports describe the use of titanium mesh for reconstruction of premaxilla. Autogenous bone grafts were harvested from the iliac crest and were loaded on a titanium mesh that were left in the patient's maxilla for 6 months before they were removed respectively. The radiographic analysis demonstrated that a 10mm vertical ridge augmentation had been achieved. In guided bone regeneration, the quantity of bone regenerated under the barrier has been demonstrated to be directly related to the amount of the space under the membrane. This space can diminish as a result of membrane collapse. To avoid this problem which involved the use of a titanium mesh barrier to protect the regenerating tissues and to achieve a rigid fixation of the bone segments, were used in association with autologous bone in 2 cases. The aim of this study was to evaluate the capability of a configured titanium mesh to serve as a mechanical and biologic device for restoring a vertically defected premaxilla.

• Journal of Periodontal and Implant Science
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• 제26권1호
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• pp.80-88
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• 1996

The aim of the present investigation was to see the effect of combined use of PDGF BB and IGF -1 on the guided tissue regeneration(GTR) using barrier membrane in the treatment of human furcation involvement. Twelve patients with initially diagnosed as having moderate to advanced adult periodontitis with mandibular class II buccal furcation defects have been wer selected. Initial scaling and root planing has been performed and baseline data consisting of probing depths and attachment levels have been recorded prior to surgical procedures. The GTR procedures using either barrier membrane(control : ePTFE) alone or together with the application of PDGF - BB and IGF -l(experimental : ePTFE+PDGF/IGF) have been done under the routine guidelines. During the surgery, the distance from CEJ either to the bottom of the bone defects(CEJ - BD) or to the bone crest(CEJ-BC) were measured. Horizontal distance to the deepest area in the furcal defects were measured from the reference line connection the most prominent bony walls of the two buccal roots. 6 months following the GTR therapy, all the measurements were made repeatedly. The probing attachment gain of the experimental and the control grous were 2.14mm and l.07mm, respectively with no statically significnant difference. Amont of vertical bone fill in the experimental and the control groups were 2.43mm and 2.29mm, rexpectively. Amonut of horizontal bone fill were 2.86mm in the experimental group and 2.17mm in the control group, respectively. However, there were no significant differences in the amount of bone fill(both vertical and horizontal)between the two groups.

• Journal of Periodontal and Implant Science
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• 제27권3호
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• pp.633-645
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• 1997

The recent trend of research and development on guided tissue regeneration focuses on the biodegradable membranes, which eliminate the need for subsequent surgical removal. They have demonstrated significant and equivalent clinical improvements to the ePTFE membranes. This study evaluate guided tissue regeneration wound healing in surgically induced intrabony periodontal defects following surgical treatment with a synthetic biodegradable membranes, made from a copolymer of glycolide and lactide, in 8 beagle dogs. After full thickeness flap reflection, exposed buccal bone of maxillary and mandibular canine and premolar was removed surgically mesiodistally and occlusoapically at $6mm{\times}6mm$ in size for preparation of periodontal defects. In experimental sites a customized barrier was formed and fitted to cover the defect. Flap was replaced slightly coronal to CEJ and sutured. Plaque control program was initiated and maintained until completion of the study. In 4, 8, 16 and 24 weeks after surgery, the animals were sacrificed and then undecalcified specimens were prepared for histologic evaluation. Histologic examination indicated significant periodontal regeneration characterized by new connective tissue attachment, cementum formation and bone formation. These membranes showed good biocompatibility throughout experiodontal period. The barriers had been completely resorbed with no apparent adverse effect on periodontal wound healing at 24 weeks. These results implicated that present synthetic biodegradable membrane facilitated guided tissue regeneration in periodontal defect.

• Applied Microscopy
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• 제33권4호
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• pp.261-266
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• 2003

소 뇌 미세혈관에서 분리한 내피세포(BBMECs)를 직경 $3.0{\mu}m$및 $0.4{\mu}m$인 구멍을 가지는 다공성막(Transwell)에서 일차배양하였을 때의 특징을 전자현미경을 사용하여 살펴보았다. 분리된 모세혈관의 작은 조각과 분리된 내피세포들은 콜라겐으로 도포한 배양기구의 표면에 고착되어 성장하였다. BBMECs들은 직경 $0.4{\mu}m$인 다공성막의 위쪽 구획에서만 성장하였으나 직경 $3.0{\mu}m$인 구멍을 가진 막에서는 세포들이 구멍을 통해 막의 반대쪽으로 이주하여 다공성막의 아래쪽 구획에서도 성장하여 세포단층을 형성하였다. 이상의 결과로 효소 처리에 의해 분리한 BBMECs는 직경 $0.3{\mu}m$의 다공성막을 통과하나 직경 $0.4{\mu}m$의 다공성막을 통과할 수 없음을 알 수 있었으며, 약물이동도를 관찰하는 실험이나 전기저항을 측정을 목적으로 하는 실험에서는 $3.0{\mu}m$의 다공성막을 사용하는 대신 $0.4{\mu}m$ 크기의 다공성막을 사용해야 한다는 것을 알 수 있었다.

• 멤브레인
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• 제26권1호
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• pp.1-13
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• 2016

연료전지는 화석연료, 특히 내연기관을 대체할 수 있는 가장 대표전인 에너지 기술이다. 가장 중요한 핵심 재료 중 하나로서 연료기체의 장벽 역할을 함과 동시에 수소이온전달 역할을 하는 고분자 전해질 막(PEM)이 있다. PEM 내부에서 수화 채널은 수소이온의 전달통로 역할을 하기 때문에, 많은 연구자들은 높은 함수율을 저가습 상태에서도 유지하여 우수한 수소이온 전달 능력을 보유할 수 있는 상분리현상을 통한 친수성 채널 형성에 대하여 초점을 맞추어 왔다. 본 총설에서는 이러한 낮은 가습조건에서도 높은 수소이온전도도를 갖는 술폰화 PEM들의 합성 전략에 대하여 논의 하여보고, 다른 연구자들의 고성능 탄화수소계 PEM의 설계에 도움을 주고자 하였다.

• 전기화학회지
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• 제15권1호
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• pp.12-18
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• 2012

다양한 응용분야에서 활용될 수 있는 고체고분자연료전지의 경우 현재 상용화에 가장 큰 걸림돌이 되고 있는 것이 고가의 백금 촉매이다. 따라서 특히 최근 들어 산소환원반응에서 백금을 대체하는 물질을 개발하기 위한 연구가 전세계적으로 확산되고 있다. 그러나 촉매 개발 시 경제성 관점 외에 내구성도 고려해야 하는데, 이런 관점에서 백금과 유사한 물성과 활성이 기대되는 백금족 원소들이 한 대안이 될 것이다. 가장 백금과 유사한 물성, 활성을 나타내는 팔라듐과 칼코겐화물 형태의 루테늄이 지금까지 가장 많이 연구가 되었으며 상대적으로 이리듐, 로듐, 오스뮴은 산소환원 촉매로 많은 연구가 되지 않았다. RDE (rotating disk electrode)를 이용한 반쪽전지 실험이나 연료전지 MEA (membrane electrode assembly) 운전을 통하여 백금과 활성을 비교해보면 팔라듐 계열의 비백금 촉매가 가장 백금에 가까운 활성을 나타내고 있음을 알 수 있다. 이 논문에서는 각 백금족 원소들 기반의, 현재까지 문헌상으로 보고된 촉매조성들을 분석하여 비백금 산소환원 촉매 개발에 도움이 되고자 한다.

• Journal of Periodontal and Implant Science
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• 제44권3호
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• pp.147-155
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• 2014

Purpose: In the anterior maxilla, hard and soft tissue augmentations are sometimes required to meet esthetic and functional demands. In such cases, primary soft tissue closure after bone grafting procedures is indispensable for a successful outcome. This report describes a simple method for soft tissue coverage of a guided bone regeneration (GBR) site using the double-rotated palatal subepithelial connective tissue graft (RPSCTG) technique for a maxillary anterior defect. Methods: We present a 60-year-old man with a defect in the anterior maxilla requiring hard and soft tissue augmentations. The bone graft materials were filled above the alveolar defect and a titanium-reinforced nonresorbable membrane was placed to cover the graft materials. We used the RPSCTG technique to achieve primary soft tissue closure over the graft materials and the barrier membrane. Additional soft tissue augmentation using a contralateral RPSCTG and membrane removal were simultaneously performed 7 weeks after the stage 1 surgery to establish more abundant soft tissue architecture. Results: Flap necrosis occurred after the stage 1 surgery. Signs of infection or suppuration were not observed in the donor or recipient sites after the stage 2 surgery. These procedures enhanced the alveolar ridge volume, increased the amount of keratinized tissue, and improved the esthetic profile for restorative treatment. Conclusions: The use of RPSCTG could assist the soft tissue closure of the GBR sites because it provides sufficient soft tissue thickness, an ample vascular supply, protection of anatomical structures, and patient comfort. The treatment outcome was acceptable, despite membrane exposure, and the RPSCTG allowed for vitalization and harmonization with the recipient tissue.

• 청정기술
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• 제9권3호
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• pp.115-124
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• 2003

생물산업(bio industry)은 90년대 이래로 연평균 32%의 고성장을 하고 있다. 환경문제와 연계한 무역장벽을 극복하기 위해서는 제품생산과정에서 발생되는 오염물을 최대한 감소시키고 재활용하는 등 기업에서의 청정생산기술의 개발 및 적용을 위한 노력이 절실히 필요한 때이다. 본 연구는 폴리만뉴로닉산 생산공정에서 발생하는 공정수에 대해 경제적이며 효율적인 처리수의 재이용 방안을 강구하기 위하여 분리막 시스템의 효용성을 검토하였다. 분리막공정의 개별 적용시 U/F 10k는 40%, U/F 1k는 60%, N/F는 80%의 농축이 가능하였고 U/F 1k와 N/F를 연속적용시 90%까지 농축 가능하였다. 탈수후 여액에서 폐기되는 제품의 손실량이 많았으나, 분리막 공정의 도입으로 인하여 폐액으로부터 제품의 회수를 통하여 약 25%의 생산수율을 향상할 수 있었다.