• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.10a
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• pp.15-15
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• 2003

치과재료에 사용되는 금속재료는 주로 스테인리스강, 타이타늄, Ni-Ti, Co-Cr등과 같은 특수합금이 주로 사용되고 있다. 이들 재료는 치과 보철물과 교정재료 및 충전재료로 주로 사용되고 있으며 그 외 치과에서 사용되는 기기나 기구에도 많이 활용되고 있다. 특히 치과 보철물을 사용하여 치료를 원하는 환자가 최근에 급격히 증가하면서 임플란트 고정체와 나사 등을 이용한 치료법의 연구와 개발이 필요하게 되어 세계적으로 연구와 투자가 활발히 진행되고 있다. 그러나 재료의 설계나 합금의 설계 및 제품의 설계상의 문제로 인하여 생체조직과 결합하는데 많은 문제점이 임상적으로 발생되고 있다. 즉 임플란트 표면의 생체적합성부여, 고정체와의 결합시 파절이나 풀림현상, 골에 고정체로 사용하는 나사의 강도와 내마모성문제 등이 개선되어야 할 문제점으로 남아있다. 또한 총의치에 사용되는 자석 어태치먼트의erosion-corrosion문제, 교정선의 탄성 과 마모저항문제 등은 앞으로 계속적인 연구를 행하여야할 과제로 남아있다. 또한 국소의치에서 사용되는 frame은 정밀주조법을 통하여 제조하며 주조상의 결함 등으로 인한 클라스프의 파절 문제점이 발생되고 있다. 따라서 본 연구에서는 치과재료로 사용되는 임플란트 고정체, 나사, 교정용 선등의 문제점을 고찰하고, 지금까지 이루어진 연구를 중심으로 최적의 개선 조건을 찾고자하였다. 최근첨단소재 및 금속재료를 사용하여 치과재료 합금을 설계할 수 있는 연구가 활발히 진행된다면 수입에 의존하고 있는 고가의 치과재료를 값이 싼 고성능의 제품으로 대체할 수 있는 효과가 클 것으로 생각된다.>$\rho$$\sub$0/=1.8 %. As t$\sub$Co/ increases, a transition from the regime of co-existence of superparamagnetic and ferromagnetic behaviors to ferromagnetic behavior was observed. Tunneling barrier called "decay length for tunneling" for the films having the thickness of Co layer from 1.4 to 1.6 nm was measured to be ranged from 0.004 to 0.021 ${\AA}$$\^$-1/.문에 기업간 관계를 연구하는 측면에서는 탐험적 연구성격이 강하다. 더 나아가 본 산업의 주된 연구가 질적이고 기업내부만을 연구했던 것에 비교하면 시초적이라고 할 수 있다. 또한 관계마케팅, CRM 등의 이론적 배경이 되고 있는 신뢰와 결속의 중요성이 재확인하는 결과도 의의라고 할 수 있다. 그리고 신뢰는 양사 간의 상호관계에서 조성될 수 있는 특성을 가진 반면, 결속은 계약관계 초기단계에서 성문화하고 규정화 할 수 있는 변수의 성격이 강하다고 할 수가 있다. 본 연구는 복잡한 기업간 관계를 지나치게 협력적 측면에서만 규명했기 때문에 많은 측면을 간과할 가능성이 있다. 또한 방법론적으로 일방향의 시각만을 고려했고, 횡단적 조사를 통하고 국내의 한 서비스제공업체와 관련이 있는 컨텐츠 공급파트너

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.193-200
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• 2008

Statement of problem: There have been a few studies about unsplinted implant retainted maxillary overdenture. Purpose: The purpose of this study was to examine the effect of different position of implant for 2 implants-retained maxillary overdenture. Materials and methods: Three-dimensional finite element models were used to reproduce an edentulous human maxilla with an implant-retained overdenture. Two implants in the canine tooth positions on both side and in the second premolar tooth positions on both side models were examined. Axial loads of 100 N were applied to the occlusal surface at the right first molar tooth positions. Maximum stress at the implant-bone interface and stress at the cortical bone surface just under the loading point were observed. Results and conclusion: Within the limits of this study, maximum stresses were concentrated around implant of canine position at loading side. The second premolar area was thought to be more favorable to distribution of stress on mucosa, alveolar bone and implants than canine area for maxillary overdenture.

• The korean journal of orthodontics
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• v.36 no.5
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• pp.339-348
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• 2006

Objective: With development of the skeletal anchorage system, orthodontic mini-implant (OMI) assisted on masse sliding retraction has become part of general orthodontic treatment. But compared to the emphasis on successful anchorage preparation, the control of anterior teeth axis has not been emphasized enough. Methods: A 3-D finite element Base model of maxillary dental arch and a Lingual tipping model with lingually inclined anterior teeth were constructed. To evaluate factors influencing the axis of anterior teeth when OMI was used as anchorage, models were simulated with 2 mm or 5 mm retraction hooks and/or by the addition of 4 mm of compensating curve (CC) on the main archwire. The stress distribution on the roots and a 25000 times enlarged axis graph were evaluated. Results: Intrusive component of retraction force directed postero-superiorly from the 2 mm height hook did not reduce the lingual tipping of anterior teeth. When hook height was increased to 5 mm, lateral incisor showed crown-labial and root-lingual torque and uncontrolled tipping of the canine was increased.4 mm of CC added to the main archwire also induced crown-labial and root-lingual torque of the lateral incisor but uncontrolled tipping of the canine was decreased. Lingual tipping model showed very similar results compared with the Base model. Conclusion: The results of this study showed that height of the hook and compensating curve on the main archwire can influence the axis of anterior teeth. These data can be used as guidelines for clinical application.

• Journal of Yeungnam Medical Science
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• v.7 no.1
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• pp.81-93
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• 1990

The author fractographically analyized the cause of metal failure(the first time this procedure has been used for this metal failure)and also analyized it clinically. In this study, I selected eight cases which have been analyized fractographically. In all these cases, the analysis was done after treatment of metal failure of implants internally fixed to femur shaft fractures at the Department of Orthopedic Surgery, Yeung-Nam University Hospital during the six year period from May 1983 to September 1989. 1. Metal failure occured in five dynamic-compression plates, one Jewett nail, one screw in Rowe plate, and one interlocking nail. 2. The clinical cause of metal failure was deficiency of medial butress in five cases, incorrect position of implant in one case, and incorrect selection of implant in two cases. 3. The time interval between internal fixation and metal failure was four months in one case, between five months to twelve months in six cases, three years in one case. 4. The fractographically analytical cause of metal failure was ; first, impact failure, one case, second, fatigue failure, six cases, machining mark(stress liser), four cases type : low consistent cyclic fatigue failure irregular cyclic fatigue failure third, stress corrosion crack, one case. 5. 316L Stainless Steel has good resistance to corrosion. However, when its peculiar surface film is destroyed by fretting, it shows pitting corrosion. This is, perhaps, the main cause of metal failure. 6. It is possible that mechanical injury occured in implants during the manufacturing of implants or that making a screw hole is the main cause of metal failure.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.3
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• pp.221-239
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• 2010

Bone loss may occur depending on the loading conditions. careful treatment planning and prosthetic procedures are very important factors for the proper distribution of stress. Evaluate the stress distributions according to numbers and location of implants in three-unit fixed partial dentures. A mandible missing the right second premolar, first molar and second molar was modeled. Using the CT data. we modeled a mandible with a width of 15mm, a height of 20mm and a length of 30mm, 2mm-thickness cortical bone covering cancellous bone mallow. An internal type implant and A solid type abutment was used. A model with 3 implants placed in a straight line, offset 1.5 mm buccally, offset 1.5 mm lingually and another model with 3 implants offset in the opposite way were prepared. And models with 2 implants were both end support models, a mesial cantilever model and a distal cantilever model. Three types of loading was applied; a case where 155 N was applied solely on the second premolar, a case where 206 N was applied solely on the second molar and a case where 155 N was applied on the first premolar and 206 N was applied on the first and second molar. For all the cases, inclined loads of 30 degrees were applied on the buccal cusps and vertical loads were applied on the central fossas of the teeth. Finite element analysis was carried out for each case to find out the stress distribution on bones and implants. This study has shown that prostheses with more implants caused lower stress on bones and implants, no matter what kind of load was applied. Furthermore, it was found out that inclined loads applied on implants had worse effects than vertical loads. Therefore, it is believed that these results should be considered when placing implants in the future.

• Clinics in Shoulder and Elbow
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• v.13 no.1
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• pp.40-46
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• 2010

Purpose: The aim of this study was to evaluate the usefulness of arthroscopic Bony Bankart repair using a One Anchor Double Fixation Technique. Materials and Method: Seventeen patients with a Bony Bankart lesion were treated using the One Anchor Double Fixation Technique (OADF Technique). There were 13 males and 4 females. The average age was 24 years (range 17-42). The average follow-up period was 22.3 months. One 3.0 mm suture anchor with doubly loaded sutures was inserted into the glenoid rim. One suture strand was passed the around the small bony fragment and tied first. Another suture strand was passed through the capsule and tied over the bony fragment. The result was measured using Rowe's evaluation index & KSS score. The glenoid defect & bony fragment were measured by 3D-CT scan. Results: Rowe's evaluation index on the final follow-up showed an overall improvement from an average of 54 (range, 23-71) to 83.4 (range 71-90). Of the 17 cases, 13 were excellent, 3 were good, and 1 was fair. KSS scores showed improvement from an average of 71 (range 49-82) to 92.5 (range 82-94). There were no cases where pain continued to the final follow-up, and no cases being re-dislocated during the follow-up period. For six cases, we confirmed the bony healing of the bony Bankart lesion by CT. Conclusion: Bony Bankart lesion repair using this new method achieves excellent clinical results with low recurrence rates and is considered another choice for bony Bankart lesions.

• Journal of Yeungnam Medical Science
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• v.13 no.1
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• pp.116-133
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• 1996

The biocompatibility of the titanium has been estabilished through various experimental studies such as cell culture toxicity test, pyrogen test, mutagen test and others. In order to confirm biocompatibility after fabrication of titanium and to clarify the difference between the bone reaction after insertion of the lathed titanium rods and the bone reaction after insertion of the finished and polished rods, both rods were implanted into the proximal femur of a rabbit. Histologic reactions in the bone were observed according to the ASTM standards at the intervals of 6 weeks, 12 weeks and 26 weeks after implantation. The result were as follows : In 6 weeks after implantation of lathed titanium rods, inflammatory reactions, such as minimal degree infiltration of polymorphonuclear leukocytes and lymphocytes were observed in all cases. This was thought to he caused by surgical trauma. However, inflammatory cell infiltration was not seen after implantation of polished and finished rods in all cases. The cellular infiltration and the histologic reaction of the hone after implantation of lathed group were significantly more pronounced than those after implantation of the finished group. In 12 weeks after implantation of lathed rods, two of four cases revealed a minimal degree of cellular infiltration. No inflammatory cell infiltration was demonstrated after implantation of the finished group. The cellular infiltration and histologic reaction seemed to be more pronounced in the lathed group, but they were not significant statistically. At 26 weeks after implantation of the lathed and finished group, there was no cellular infiltration in both groups. New bone formation was observed up 26 weeks, and no difference between lathed titanium rods and finished titanium rods were apparent. Mild bone necrosis was observed in 1 case out of 11 cases in which lathed titanium rods were implanted. Bone necrosis was not observed in the finished titanium rod group. Fibrosis was observed in both groups, but differences were not significant between the experimental groups. In the lathed titanium rods group and the shorter interval group, inflammatory cell infiltration was significantly higher. Finished titanium rods and longer interval groups had markedly decreased tendences in histologic reaction ratings. As a conclusion, although certificated titanium might be safe to use, difference of biocompatibility were observed depending on the method of surface finish. By identifying biocompatibility as a long-term standardized animal study, we can develop progressed internal fixation device that is safe for human beings.

• Journal of Korean Foot and Ankle Society
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• v.13 no.2
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• pp.169-174
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• 2009

Purpose: To evaluate the clinical results between interlocking intramedullary nail with fibular fixation and nail only for treating distal tibiofibular diaphyseal fractures. Materials and Methods: From March 2003 to September 2006, 19 distal tibiofibular fractures were antegrade nailed after anatomical reduction and fixation of fibular fractures, and another 37 fractures fixed with nails only. Average age of patients was 48.6 years. These two groups were compared by VAS (visual analogue scale) & ankle ROM according to degree of comminution and fracture configuration. The statistical analysis was evaluated by t-test. Results: There was no statistical difference between fibular fixation group and non-fixation group in VAS score according to fracture comminution and configuration (p>0.05). However, compared according to fracture configuration, mean ankle eversion of fibular fixation group in oblique fractures was 18.3 degrees, and that of non-fixation group was 12.5 degrees (p<0.05). In addition, mean ankle plantar flexion, dorsiflexion, inversion and total ankle ROM of fibular fixation group in spiral fractures was 40.0, 20.0, 30.0 and 108.3 degrees of each and that of non-fixation group was 38.3, 18.5, 27.0 and 101.7 degrees (p<0.05). Conclusions: In oblique and spiral fractures of distal tibiofibular diaphysis, interlocking intramedullary nail with fibular fixation had the advantage in postoperative ankle ROM. So, it can be a worthy method for the treatment of distal tibiofibular diaphyseal fractures.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.1
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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.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1991.06a
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• pp.30-30
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• 1991

성대마비 이비인후과 영역에서는 비교적 빈번하게 관찰되는 질환으로 대부분은 미주신경과 그 분지인 반회신경이 경정맥공에서 후두까지의 주행중에 생긴 질환에 의하여 이차적으로 발생하거나, 드물게는 윤상갑상연골 관절의 고정에 의사여 발생하게 된다. 임상적인 진단은 간접후두경이나 화이버옵틱후두경 검사법에 의하여 간단하게 내려질 수 있으나, 그 발생원인은 다양하며, 임상적인 양상 및 그에 따른 치료 원칙도 다르게 나타난다. 이에 연자들은 1986년 1월 1일부터 1990년 12월 31일까지 5년간 국립의료원 이비인후과에 내원한 환자중 성대마비로 진단된 환자 61례에 대한 후향적 기록 분석에 의해 성별, 원인별, 측별, 성대의 위치, 및 그에 따른 치료방향에 대하여 비교 검토하여 다음과 같은 결과를 보였다. 1)성별은 남녀비가 3:2로 남자가 많았으며, 연령별 분포는 20대에서 70대까지 비교적 균등하였으나 50대(23.0%)에서 가장 많은 분포를 보였다. 2)원인으로는 원인불명이 16례(26.2%), 갑상선수술 8례(13.1%), 폐결핵과 기관내삽관후 각각 6례(9.8%), 폐암 5례(8.2%) 순이었다. 3)마비된 성대의 측별 분포는 편측성이 51례(83.6%), 양측성이 10례(16.4%)이며, 편측성중 좌측이 37례(60.6%)로 가장 많았다. 마비된 성대의 위치는 부정주위가 33례(54%)로 가장 많았다. 4)즉 증상은 단지 애성만 있었던 례가 31례(50.8%), 호흡곤란 혹은 기도흡인등을 동반한 애성이나, 애성을 동반하지 않은 례도 있었다(3례). 증상 발현후 병원 내원까지 기간은 2개월이내가 가장 많았다. 5)16례에서 수술적 처치가 시행되었거나(9례), 혹은 자연치유가 관찰되었는데(7례) 편측성마비때 갑상연골성형술 2례, 양측 마비때 후두외접근법에 의한 피열연골절제술 4례, 레이저를 이용한 피열연골절제술 2례, 승모판 협착증에 의한 편측성 성대마비에서 개심술후 성대마비 회복 1례, 자연 치유는 7례에서 관찰되었으며 6례에서는 증상발현후 6개월이내에 회복되었다.