• Clinics in Shoulder and Elbow
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• 제8권1호
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• pp.19-22
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• 2005

Purpose: The causes of twelve cases of the mid-shaft clavicle nonunion and the results of internal fixation with plate and bone graft were investigated. Materials and method: From August 1997 to March 2003, twelve cases of the mid-shaft clavicle nonunion were operated with internal fixation with plate and bone graft. The duration of follow-up was average 13 months. Results: The causes of the mid-shaft clavicle nonunion included severe associated injury, severe initial displacement of the fracture fragments and insecure fixation. All cases were operated with internal fixation with plate and bone graft. According to the factor for evaluations of results, using a rating scale of excellent (no apparent factors), good (one factor), fair (two factors), poor (more than three factors), the results showed 10 excellent, 1 good and 1 poor. Screw loosening was developed in only one case . Conclusion: The internal fixation with plate and bone graft of the mid-shaft clavicle nonunion after failed conservative treatment achieved excellent results and seemed to be the procedure of choice for mid-shaft clavicle nonunion.

• Archives of Reconstructive Microsurgery
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• 제16권2호
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• pp.125-132
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• 2007

Introduction: Ulna is nearly equal to radius in function and bony architecture and strength in forearm. But in lower extremity, fibula is 1/5 of tibia in anatomic and functional point so we can find fibula transposition is commonly used in defect of tibia. We cannot find other article about segmental forearm bone transposition in man. The purpose of this study was to report our clinical and functional result of undergoing segmented transposition of ipsilateral ulna with its own vascular supply in defect of radius in 6 cases. Material and method: From June 1994 to October 2007, 7 segmented bone transpositional grafts in forearm were performed in Kyung Hee Medical Center. The distribution of age was from 20 years old to 73 years old. There was male in 6 cases and female in 1 case. The causes of operation were giant cell tumor in 1 case and traumatic origin in 6 cases; it was nonunion in 2 cases and fracture with severe comminution in 4 cases. Ipsilaterally segmented ulna keeping its own vascular supply was transported to defect of radius in severe traumatic patients and one patient whose tumor in radius had been excised. Transported ulna was fixed to proximal and distal radius remnants by plate and screw. In one case with giant cell tumor, transported ulna was connected to radius across wrist joint as wrist joint fusion. Joint preserving procedures were performed in 6 cases with crushing injury of radius. Results: We could obtain solid bony union in all cases and good functional results. The disadvantage was relative shortening of forearm, but we could overcome this problem. Conclusion: We think that ipsilateral segmented ulna transposition keeping its own vascular supply to radius can be perfomed with one of procedures in cases with wide defect in radius.

• 대한치과기공학회지
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• 제40권1호
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• pp.41-47
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• 2018

Purpose: The purpose of this study was to analyze the biomechanical properties of the dental implants on the supporting bone using three-dimensional finite element method when three different abutment materials were applied to the implant system. Methods: Three different dental implant models were fabricated by applying Ti, PEEK, and CRE-PEEK (60% carbon-reinforced PEEK) to abutment material. The abutment and connecting screw from the fixture was applied with a tightening torque of 20 Ncm. And then, total loads of 150 N were applied in an $30^{\circ}oblique$ direction (to the vertical). The structural stability of dental implants on the supporting bone was analyzed using Von Mises stress and principal stress values. Results: The maximum tensile stress of the cortical bone was highest at 12.6 MPa in the PEEK abutment (Model-B). Ti abutment (Model-A) and CRE-PEEK abutment (Model-C) showed similar stress distributions (10.6 and 10.3 MPa, respectively). And the maximum compressive principal stress was similar in all models. The Von Mises stress value delivered to the bone around the implant was highest at 16.5 MPa in Model-B. On the other hand, Model-A and C showed similar stress distributions (14.0 and 13.8 MPa, respectively). In addition, the maximum equivalent stress applied to the abutment was highest at 629.8 MPa in Model-A. The stress distribution in Model-C was 573.9 MPa. Whereas, Model-B showed the lowest value at 165.6 MPa. Conclusion : The dental implant supporting bone system using PEEK material seems to have the possibility of supporting bone fracture. It was found that the CRE-PEEK abutment can reduce the elastic deformation and reduce the stress value of the interfacial bone.

• 대한골관절종양학회지
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• 제4권2호
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• pp.81-87
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• 1998

Although autoclaved autogenous bone reconstruction is one of the established procedures, it may have some problems in bone regeneration and mechanical property. The purpose of this study is to evaluate the efficacy of more biologic and anatomical reconstruction where allograft is not readily available. From Aug.1991 to Feb. 1996 the authors analyzed 32 cases of reconstruction with autogenous low heat treated bone. Autogenous graft sites were humerus 4, tibia 4, pelvis 9, and 15 femur. Average follow-up period was 23(range;12-51) months. There were 49 graft-host junctional sites. Diaphysis was 22, metaphysis 10, and flat bone 17. Average duration of healing for the 38 united sites was 7 months. Average union time for each anatomical area 8 months in 19 diaphysis, 12 months in 7 metaphysis, and 12.7 months in 12 flat bone(pelvis). Eleven nonunion sites consisted of 3 diaphysis(3/22), 3 metaphysis(3/10), and 5 flat bone(5/17). Complications other than nonunion were local recurrence(4), bone resorption(3), graft fracture(2), osteomyelitis(1), metal failure(2), and wound infection(1). Initial bone quality and stable fixation technique was important for union rate. Plate and screw is a good method for diaphyseal lesion. Metaphyseal and flat bone are weak area for rigid fixation and one stage augmentation with iliac bone graft can be a salvage procedure.

• Composites Research
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• 제26권3호
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• pp.170-174
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• 2013

상온 상압 플라즈마 표면처리된 목분을 폴리프로필렌(polypropylene)과 혼합하였을 때 두 재료의 계면에 미치는 영향을 연구하였다. 목분과 폴리프로필렌을 압출기를 통해 기계적으로 혼합한 후 사출기를 이용하여 목분함유량 50 wt% 목분/폴리프로필렌(Wood Plastic Composite, WPC) 복합재를 제조하였다. 플라즈마 표면처리 공정에 가장 적합한 Monomer(모노머)를 찾기 위해 Oxygen, Benzene, CH-4, Acrylic-acid, Hexafluoroethane, Trifluorotolune, Hexamethyl-disiloxane(HMDSO) 등 7가지의 모노머에 대해 Contact angle(접촉각)을 측정하여 표면에너지를 계산하였다. 그 결과 HMDSO가 가장 높은 표면에너지를 나타내어 플라즈마 공정의 모노머로 적용하였다. 소수성인 폴리프로필렌과 친수성인 목분을 플라즈마 표면처리를 통하여 목분의 표면을 개질하였고 두 재료의 계면 결합력을 향상시킬 수 있었다. 기계적 물성평가 결과는 인장강도의 경우 최대 7.59%, 굴곡강도의 경우 최대 12.43%가 증가하였다. SEM(Scanning Electron Microscope)을 이용하여 파단면을 관찰하였고 플라즈마 표면처리의 효과를 확인하였다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권6호
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• pp.285-290
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• 2014

Objectives: We compared resorbable plates with titanium plates for treatment of combined mandibular angle and symphyseal fractures. Materials and Methods: Patients with mandibular angle and symphysis fractures were divided into two groups. The control (T) group received titanium plates while the experimental (R) group received resorbable plates. All procedures were carried out under general anesthesia using standard surgical techniques. We compared the frequency of wound dehiscence, development of infection, malocclusion, malunion, screw breakage, and any other technical difficulties between the two groups. Results: Thirteen patients were included in the R group, where 39 resorbable plates were applied. The T group consisted of 16 patients who received 48 titanium plates. The mean age in the R and T groups was 28.29 and 24.23 years, respectively. Primary healing of the fractured mandible was obtained in all patients in both groups. Postoperative complications were minor and transient. Moreover, there were no significant differences in the rates of various complications between the two groups. Breakage of 3 screws during the perioperative period was seen in the R group, while no screws or plates were broken in the T group. Conclusion: Resorbable plates can be used to stabilize combined mandibular angle and symphysis fractures.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권2호
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• pp.127-135
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• 2009

Objectives : The titanium fixation system has been used in orthognathic surgery for fixation of bone segments usually, but the biodegradable fixation system was developed and also being used. The strongest point in the biodegradable system is that no extra operation should be needed to remove fixation materials. In spite of this merit, oral & maxillofacial surgeons hesitate to use this system in fracture or orthognathic surgery. In this study, as we got some clinical experiences, we'd like to report the result of clinical study using the biodegradable fixation system in orthognathic surgery. Patients and Methods : A total of 35 patients composed of 17 males and 18 females with 25 osteotomies in maxilla and 34 osteotomies in mandible were fixated with the biodegradable fixation system(Inion $CPS^{(R)}$). We investigated methods of stabilization, fixation time, and complications on the basis of the method as above. Results : Four 2mm thick L shaped plates with 7 holes of which 1 hole was removed were fixed in maxilla with six $2.0{\times}7mm$ screws. Three $2.5{\times}16{\sim}18mm$ screws were used to fix superior ramus area and one mandibular angle area in mandible. It took about 27.4 minutes in maxilla, 25.3 minutes in mandible to perform the fixation which took longer time than the titanium system(9.5 minutes in maxilla, 8 minutes in mandible). Generally, there was no problem except 9 cases in which there were some complications. Conclusions : In most cases, the biodegradable fixation system can be used without problem in usual orthognathic surgery. But, this system is inferior to the titanium fixation one in some respects such as fixation time, size, and physical property. Some supplementations for such weak points as aforementioned should be needed for the universal use of biodegradable materials.

• 대한심미치과학회지
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• 제28권2호
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• pp.64-73
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• 2019

심한 치조골의 위축과 흡수로 인한 형태학적 변화는 임플란트의 성공적인 식립과 임플란트의 골유착에 영향을 미친다. 이를 극복하기 위한 다양한 골증대술 중 치조제분할술은 좁은 치조골 폭을 성공적으로 증대시키는 수술방법으로 보고되었다. 또한 다양하게 개발되는 임플란트 디자인과 치조제 팽창 기구 등은 심하게 흡수된 위축된 하악부위에서도 협측골 파절을 최소화할 수 있다. 가철성 부분의치의 사용으로 심하게 흡수된 하악 구치부에 치조제 분할술과 최소 크기의 블록형 골이식술을 이용해 한개의 스크류로 수용부의 고정을 획득한 후 동시적 접근법을 이용한 골이식 증례를 보고 하고자 한다. 보철과와 치주과의 협업으로 환자의 기능과 심미를 회복해준 증례로 사료된다.

• 접착 및 계면
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• 제15권1호
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• pp.14-21
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• 2014

본 연구에서는 이축압출기와 사출기를 사용하여 폴리유산(PLA)와 폴리부틸렌숙시네이트(PBS) 수지의 함량비를 달리하여 PLA/PBS 블랜드를 제조하고, 그들의 기계적, 열적 특성 및 모폴로지를 조사하였다. PLA/PBS 블랜드의 굴곡강도, 굴곡탄성률, 인장강도 및 인장탄성률과 같은 기계적 특성, 그리고 용융거동, 동역학적 열특성 및 열안정성과 같은 열적 특성이 PLA와 PBS 함량비에 크게 의존하였다. 그러나 PLA/PBS 블랜드의 열변형온도는 PLA 또는 PBS 함량 변화에 크게 영향을 받지 않았다. 또한 PLA/PBS 블랜드의 파단면은 PBS 함량이 증가함에 따라 brittle 양상으로부터 ductile 양상으로 변화되었다.

• 한국기계가공학회지
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• 제17권6호
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• pp.24-30
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• 2018

Dental implants are currently widely used as artificial teeth due to their good chewing performance and long life cycle. A dental implant consists of an abutment as the upper part and a fixture as the lower part. When chewing forces are repeatedly applied to a dental implant, gap at the interface surface between the abutment and the fixture is often occurred, and results in some deteriorations such as loosening of fastening screw, dental retraction and fixture fracture. To cope with such problems, a sealing-type abutment having a number of grooves along the conical-surface circumference was previously developed, and shows better sealing performance than the conventional one. This study carries out optimization of the groove shape by genetic algorithm(GA) as well as structural analysis in consideration of external chewing force and pretension between the abutment and the fixture. The overall optimization system consists of two subsystems; the one is the genetic algorithm with MATLAB, and the other is the structural analysis with ANSYS. Two subsystems transmit and receive the relevant data with each other throughout the optimization processes. The optimization result is then compared with that of the conventional one with respect to the contact pressure and the maximum stress. The result shows that the optimized model gives better sealing performance than the conventional sealing abutment.