• 대한기계학회논문집A
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• 제33권4호
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• pp.430-439
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• 2009

Posterior Cruciate Ligament (PCL) plays an important role in knee extension. Rotational instability due to injured PCL can be restored by various PCL reconstruction methods. In this study, the initial lengthening affected by fixation device and location was demonstrated, and furthermore, the slippage and the relationship between lengthening ratio and slippage ratio in the calcaneus and soft tissue fixation methods was newly suggested. Eight specimens of proximal tibia and Achilles tendon grafts were harvested from four cadavers and divided into four groups in regard to the four different types of transtibial fixation techniques. The cyclic load ranged from 50 N to 250 N applied to each graft fixed to proximal tibia in 55 degrees. The initial lengthening ratio to the total elongation has been approximately constant regardless of the fixation methods. The soft tissue fixation method with an interference screw showed about 56.4% slippage ratio to the total elongation and the same method with a double cross-pin presented about 45.4% slippage ratio. The soft tissue fixation method with an interference screw demonstrated approximately 2 mm less total elongation and about 13% more slippage than lengthening because of poor fixation compared to the same method with a double cross-pin.

• 대한치과보철학회지
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• 제35권2호
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• pp.373-384
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• 1997

In this study, 4 types of dowel pin were used to fabricate removable dies using the Pindex system. The comparison of interabutment distances between before and after sawing were conducted in each type of dowel pin, and the horizontal discrepancies in the interabutment distance according to the abutment location and the type of dowel pin were comparatively analyzed. Abutments LM(left molar), LP(left premolar), A(anterior), RP(right premolar), and RM (right molar) were used for measurement. The interabutment distances were measured between each abutment : LM-LP, LM-A, LM-RP, and LM-RM. The slide scanned image of each model was magnified on the computer screen and the measurements were conducted using the meeting point of the cross on the occlusal surface of each abutment. The results were as follows : 1. In the comparison of interabutment distances between before and after sawing in each type of dowel pin, there was no significant difference in World dowel pin(double), Bi-pin(double), Maxcel dowel pin(single). In the World dowel pin(single) there was no significant difference between LM-LPs, but in the other measurements (LM-As, LM-RPs, and LM-RMs) there was significant difference between before and after sawing(p<0.05). 2. In comparison of horizontal discrepancies of the measurement according to the abutment location, there was significant difference between measurement LM-LP($0.27{\pm}0.19mm$) and the others : LM-A($0.46{\pm}0.20mm$), LM-RP($0.38{\pm}0.25mm$), LM-RM($0.45{\pm}0.22mm$) (p<0.05). 3. In comparison of horizontal discrepancies of the measurement according to the type of dowel, there was no significant difference between each dowel. As a result when fabricating a removable die using the previously mentioned 4 types of dowel pins, it is thought that the horizontal discrepancy increased in proportion to the interabutment span length and does not depend on the type of dowel pin.

• 구강회복응용과학지
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• 제32권1호
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• pp.80-86
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• 2016

잔존 지대치의 수가 적은 경우 이중관 가철성 국소의치를 사용한 여러 보고에서 우수한 결과가 나타남을 확인할 수 있다. 특히 치주 상태가 양호하지 않고 고립된 소수 잔존치를 지대치로 이용하여 국소의치로 수복해야 하는 경우에 프릭션핀을 이용한 하이브리드 텔레스코픽 이중관은 적절한 적응증이 될 수 있다. 본 증례는 심한 치주염으로 다수 치아 발치 후 상악은 전치부 고정성 보철 수복과 Kennedy class I 가철성 국소의치로 수복하고 하악은 양측성 고립 지대치만 남아있어 클래스프 국소의치로 수복하기에 예후가 불분명하여 프릭션핀을 이용한 하이브리드 텔레스코픽 이중관 국소의치를 이용하였다. 이중관 가철성 국소의치의 특성과 효용성을 고찰해 보고자 본 증례를 보고한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.203-204
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• 2008

• Structural Engineering and Mechanics
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• 제56권4호
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• pp.667-694
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• 2015

The suspended dome system is a new structural form that has become popular in the construction of long-span roof structures. Suspended dome is a kind of new pre-stressed space grid structure that has complex mechanical characteristics. In this paper, an optimum topology design algorithm is performed using the enhanced colliding bodies optimization (ECBO) method. The length of the strut, the cable initial strain, the cross-sectional area of the cables and the cross-sectional size of steel elements are adopted as design variables and the minimum volume of each dome is taken as the objective function. The topology optimization on lamella dome is performed by considering the type of the joint connections to determine the optimum number of rings, the optimum number of joints in each ring, the optimum height of crown and tubular sections of these domes. A simple procedure is provided to determine the configuration of the dome. This procedure includes calculating the joint coordinates and steel elements and cables constructions. The design constraints are implemented according to the provision of LRFD-AISC (Load and Resistance Factor Design-American Institute of Steel Constitution). This paper explores the efficiency of lamella dome with pin-joint and rigid-joint connections and compares them to investigate the performance of these domes under wind (according to the ASCE 7-05), dead and snow loading conditions. Then, a suspended dome with pin-joint single-layer reticulated shell and a suspended dome with rigid-joint single-layer reticulated shell are discussed. Optimization is performed via ECBO algorithm to demonstrate the effectiveness and robustness of the ECBO in creating optimal design for suspended domes.

• 구강회복응용과학지
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• 제33권4호
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• pp.284-290
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• 2017

구순구개열 환자에게 가철성 보철치료는 중요한 치료 선택 중 하나이다. 구순구개열 환자에서 만족스러운 기능적 및 심미적 결과를 얻기 위해서는 전통적인 보철 치료법에서 약간의 수정이 필요할 수 있는데, 치주 질환에 이환되어 있으며 소수의 구치만 잔존해 있는 구개열 환자의 경우 이중관에 연결된 가철성 보철이 치료 선택의 대안이 될 수 있다. 이중관이 가철성 국소의치에 연결되면 보철적 안정성과 유지를 증가시키고 치아 장축에 유리한 힘 전달을 최적화하며 심미성도 향상시킨다. 그리고 이중관 의치의 횡단치열궁안정(cross arch stabilization)은 구순구개열 환자의 갈라진 치조제의 안정화에도 도움을 준다. 본 증례는 성인 구순구개열 환자에서 마찰핀(friction pin)을 사용한 혼성 이중관 가철성 국소의치를 제작하여 유지 및 안정성과 함께 심미성도 향상시켜 만족할 만한 결과를 나타낸다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1461-1466
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• 2008

In the case of Posterior Cruciate Ligament (PCL), the most frequent mechanism is the dashboard injury, which is directly pressurized to the anterior of the proximal tibia in the state of the knee hyperflexion. The PCL associated ligament damage happens when the posterior injury, the varus, the valgus, the hyperextension and the severe vagus torque are out of the critical value of PCL. After the successful operation cases of Anterior Cruciate Ligament (ACL) reconstruction using the allograft were informed from 1986, a number of results kept over the maximum 10 years were reported. Unfortunately, PCL reconstruction are crowded the surgery techniques such as the graft, the tibia fixing method, the fixation device, the location of the femoral tunnel, the number of the graft bundles and PCL reconstruction to access to the stability of the normal joint is being developed. Therefore, this study is the basic research of these above facts. The current transtibial tunnel surgery using the cadaveric Achilles tendon grafts is chosen for the various PCL reconstruction. The initial extension of the Achilles tendon by the fixing device and its location under the cyclic loading, were observed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1527-1532
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• 2008

45% of the sports accidents is the knee damage and the representative case is the damage of an Anterior Cruciate Ligament (ACL) and the Posterior Cruciate Ligament(PCL). Although the past different views of ACL reconstruction comes to an agreement, the disputes of PCL is remained yet. The most important engineering approach for these various surgery techniques is accurately to understand and to evaluate the fatigue behavior depending on the stress flow and the stress distribution under the allotted load and the cyclic load, which are caused by the graft fixing device, the proximal tibia of the PCL reconstructing structure. Therefore, this study is the basic research of these above facts. The current transtibial tunnel surgery using the cadaveric Achilles tendon grafts is chosen for the various PCL reconstruction. The relationships between the slippage, the extension ratio, and the slippage ratio by the heel bone fixing method and the soft tissue fixing method of the Achilles tendon were also defined. This research will be the essential data to help the resonable operating techniques for the next PCL reconstruction.

• 대한관절경학회지
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• 제7권2호
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• pp.183-188
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• 2003

목적 : 전방 십자 인대 재 재건술 시행시 자가 슬괵건을 이식건으로 사용하고 대퇴 및 경골 터널은 이중으로 고정하는 방법으로 시행하여 그 치료 결과를 보고하고자 한다. 대상 및 방법 : 2000년 5월부터 2002년 7월까지 슬괵건을 이용한 전방 십자 인대 재 재건술을 시행 받고 1년이상 추시가 가능하였던 6예를 대상으로 하였다. 6예 모두 남자였으며 평균 연령은 28.3세였다. 1차 재건술 후 재 재건술까지 기간은 평균 28.9개월이었으며 재 재건술 전까지 평균 수술 횟수는 1.7회였다. 슬괵건은 네 겹으로 준비하여 이용하였으며 기존 대퇴 터널이 재 재건술에 영향을 주는 경우 대퇴 터널을 40 mm 깊이로 만들고 횡고정 핀 고정후 흡수성 간섭 나사로 이중 고정하였다. 경골 터널은 Intrafix로 고정하였고 기존 터널의 영향이 있는 경우 screw-washe로 이중 고정하였다. 술후 평가는 Lysholm 점수, IKDC (International Knee Documentation Committee) 평가 기준, KT-2000 관절계를 이용하여 평가하였다. 결과 : 최종 추시상 Lysholm 점수는 술전 77.2점에서 술후 87.7점으로 호전되었고 IKDC 평가 기준상 술전 B 1예, C 4예, D 1예에서 술후 A 1예, B 4예, C 1예로 5예$(83\%)$에서 B이상의 결과를 보였다. KT-2000 관절계를 이용한 최대 도수 부하 검사상 술전 평균 4.5 mm에서 술후 1.8 mm로 호전되었다. 결론 : 전방 십자 인대 재 재건술시 슬괵건은 좋은 이식물로 사료되며, 수술시 기존 터널의 영향이 있는 경우 이중 고정 방법은 좋은 방법으로 사료된다.