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하악 전돌증 환자의 악교정 수술에서 기도 공간의 부피변화에 관한 3차원적 분석
이지호,팽준영,명훈,황순정,서병무,최진영,이종호,정필훈,김명진,Lee, Jee-Ho,Paeng, Jun-Young,Myoung, Hoon,Hwang, Soon-Jung,Seo, Byoung-Moo,Choi, Jin-Young,Lee, Jong-Ho,Choung, Pill-Hoon,Kim, Myung-Jin 대한악안면성형재건외과학회 2005 Maxillofacial Plastic Reconstructive Surgery Vol.27 No.6
Orthognathic surgery changes patient's mandibular position and environment of related anatomic structures. Many clinicians were interested in these changes and studied about this problem. However, most of them were based on two dimensional cephalogram. According to the development of image and computer system, it would be possible that the airway change is analyzed with three dimensional CT. So we tried to measure the volumetric change of airway and analyzed the relationship between the airway structure and volumetric change. Nineteen patients who experienced orthognathic surgery due to mandibular prognathism were analyzed with 3D CT data (preoperative and postoperative 6 months) and 2D lateral cephalometry. Volumetric change was measured and 3 dimensional change of related structure was assessed with simulation program ($V-works^{(R)}$, 4.0 Cybermed, Korea). Ten patients showed the decrease of airway volume change and nine showed the increase of airway volume change. Volumetric change was determined by dimensional change of mandible and hyoid bone. The dimensional positions of mandible and hyoid bone were the key factor for determining the airway change after surgery. Airway change is also predictable with the dimensional change of mandible and hyoid bone.
컴퓨터보조 기반 점막지지 서지컬템프레이트를 이용한 하악전치부 임플란트 식립
이지호,김성민,김명주,박정민,서미현,명훈,이종호,김명진,Lee, Jee-Ho,Kim, Soung-Min,Kim, Myung-Joo,Park, Jung-Min,Seo, Mi-Hyun,Myoung, Hoon,Lee, Jong-Ho,Kim, Myung-Jin 대한악안면성형재건외과학회 2011 Maxillofacial Plastic Reconstructive Surgery Vol.33 No.2
A 73-year-old Korean female patient with a fully edentulous mandible was planned to have five implant fixtures installed in the anterior mandible for the fixed prosthesis. After 3-dimensional (3D) computed tomographic scanning was transferred to OnDemand3D$^{(R)}$ (Cybermed Co., Seoul, Korea) software program for the virtual planning, five fixtures of MK III Groovy RP implants of Branemark System$^{(R)}$ (Nobel Biocare AB Co., Goteborg, Sweden) were installed in the anterior mandible between both mental foramens using In2Guide$^{(R)}$ (CyberMed Co., Seoul, Korea) mucosa-supported surgical template with Quick Guide Kit$^{(R)}$ (Osstem Implant Co., Seoul, Korea) systems. Fixture installations were completed successfully without any complications, such as mental nerve injury, bony bleedings, fenestrations and other unexpected events. Postoperative computed tomographic scans were aligned and fused to the planned implant, then angular and linear deviations were compared with the planned virtual implants. The mean angular deviation between the planned and actual implant axes was $3.42{\pm}1.336^{\circ}$. The mean distance between the planned and actual implant at the neck area was $0.544{\pm}0.290$ mm horizontally and $0.118{\pm}0.079$ mm vertically. The average distance between the planned and actual implant at the apex area was $1.166{\pm}0.566$ mm horizontally and $0.14{\pm}0.091$ mm vertically. These results could be considered more precise and accurate than previous reports, and even our recent results. The entire procedures of this case are reported and reviewed.
컴퓨터 시뮬레이션 기반의 외과용 스텐트를 이용한 임플란트 시술과 영상융합기술을 이용한 평가
이지호(Jee-Ho Lee),김성민(Soung-Min Kim),팽준영(Jun-Young Paeng),김명진(Myung-Jin Kim) 대한구강악안면외과학회 2010 대한구강악안면외과학회지 Vol.36 No.5
Introduction: The planning of implant surgery is an important factor for the implant prosthesis. Stereolithographic (SLA) surgical stents based on a computer simulation are quite helpful for clinicians to perform the surgery as planned. Although many clinical and technical trials have been performed for computed tomography (CT)-guided implant stents to improve the surgical procedures and prosthetic treatment, there are still many problems to solve. We developed a system of a surgical guide based on 3 dimensional (3D) CT for implant therapy and achieved satisfactory results in the terms of planning and operation. Materials and Methods: Fifteen patients were selected and 30 implant fixtures were installed. The preoperative CT data for surgical planning were prepared after obtaining informed consent. Surgical planning was performed using the simulation program, Ondemend3D In2Guide. The stents were fabricated based on the simulation data containing information of the residual bone, the location of the nerve, and the expected design of the prostheses. After surgery with these customized stents, the accuracy and reproducibility of implant surgery were evaluated based on the computer simulation. The data of postoperative CT were used to confirm this system using the image fusion technique and compare the implant fixtures between the planned and implanted. Results: The mean error was 1.18 (±0.73) mm at the occlusal center, 1.23 (±0.67) mm at the apical center, and the axis error between the two fixtures was 3.25(±3.00). These stents showed superior accuracy in maxilla cases. The lateral side error at the apical center was significantly different from the error at the occlusal center but there were no significant differences between the premolars, 1st molars and 2nd molars. Conclusion: SLA surgical stents based on a computer simulation have the satisfactory accuracy and are expected to be useful for accurate planning and surgery if some errors can be improved.
콘크리트 손상모형을 이용한 FRP 보강 철근콘크리트 보의 해석
이지호 ( Lee¸ Jee-ho ),박영환 ( Park¸ Young-hwan ),조정래 ( Cho¸ Jung-rae ),임주은 ( Lim¸ Ju-eun ) 한국구조물진단유지관리공학회 2002 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.6 No.2
In this paper, a model for reinforced concrete beams strengthened with FRP is presented. The model consists of separate models representing concrete, reinforcing steel bars, FRP, and connection between concrete and FRP. Cracked concrete is represented by the plastic-damage model. Connection between concrete and FRP is represented by a bond-slip link model. From numerical simulation, it is shown that the proposed model effectively and realistically represents the failure behavior of reinforced concrete beams strengthened with FRP sheets. The present plastic-damage concrete model is observed to work appropriately with the reinforcing bar and FRP-concrete bond-slip link model in representing the strain localization behavior.
3D CAD 데이터 기반의 효율적 철근 요소 생성 알고리즘
조경진,이지호,Cho, Kyung-Jin,Lee, Jee-Ho 한국전산구조공학회 2009 한국전산구조공학회논문집 Vol.22 No.5
본 논문에서는 철근콘크리트 구조물의 3차원 디지털기술 기반 설계에 필요한 CAD/CAE 데이터 연동을 위하여 3D CAD 데이터로부터 철근 요소를 생성하는 2단계 알고리즘을 제안하였다. 1단계 과정은 STEP 표준형식의 3D CAD 데이터를 분석하여 여러 형태의 철근 객체 정보를 추출하는 알고리즘이며, 2단계 과정은 추출된 객체 형식의 철근 정보로부터 유한요소해석에 필요한 1차원 철근요소를 생성하는 알고리즘이다. 개발된 알고리즘을 구현하여 프로그램을 작성하였으며, 이를 사용하여 실제 3D CAD 소프트웨어로부터 생성된 철근콘크리트 구조물 데이터를 유한요소해석 데이터로 성공적으로 변환하여 제안된 알고리즘이 유효함을 보였다. In this paper a two-step algorithm is proposed to efficiently generate rebar elements from 3D CAD data in the context of CAD/CAE data transfer. The first step is an algorithm to identify various type rebar objects and their attributes by analyzing 3D CAD data in STEP format, which is one of the international data standards. The second algorithmic step is a procedure to generate one-dimensional rebar elements from the object data made through the first step for finite element analysis or other CAE tasks. Successful rebar element data generation from real 3D CAD data for a reinforced concrete structure shows the efficacy of the proposed algorithm.
고체추진기관의 유동-구조 상호작용 해석에서 Serial Staggered 기법의 수치 안정성
조현주,이지호,이창수,김종암,김신회,이정섭,Cho, Hyun-Joo,Lee, Jee-Ho,Lee, Chang-Soo,Kim, Chong-Am,Kim, Shin-Hoe,Lee, Jeong-Sub 한국전산구조공학회 2016 한국전산구조공학회논문집 Vol.29 No.2
본 연구에서는 고체추진기관의 2차원 축대칭 FSI 해석에서 CSS 및 ISS 기법의 수치 안정성을 고찰하였다. 이를 위하여 CSS 및 ISS 기법을 2차원 축대칭 FSI 수치해석 알고리즘에 구현한 프로그램을 작성하고, 이를 ACM 및 BCM 고체추진기관의 복합거동 해석에 사용하였다. 해석 결과들을 비교 분석하여 ISS 기법이 고체추진기관 FSI 해석의 수치 안정성 개선에 효과적인지 검토하였다. 연구결과, ISS 기법을 적용한 FSI 해석은 시스템 시간간격이 작아질수록 수치적 수렴성을 보이며, CSS 기법과 다르게 시간이 진행되어도 수치해의 진동이 발산하지 않는 것을 확인할 수 있었다. 이를 통하여 ISS 기법을 사용하면 ACM 및 BCM의 FSI 해석에 CSS 기법을 이용할 시 나타나는 수치 불안정성을 개선할 수 있음을 확인하였다. In this paper numerical stability of CSS and ISS schemes in axisymmetric fluid-structure-burning simulation for solid rocket motors are studied. The implemented CSS and ISS algorithms for two-dimensional axisymmetric FSI problems are used to analyze ACM and BCM solid rocket motors. Numerical results from CSS and ISS schemes are compared to investigate the efficacy of ISS scheme over CSS scheme in stabilizing the numerical solution. The ACM and BCM simulation results show that ISS scheme gives stable and converged numerical solutions with appropriately small system time step size, while CSS scheme fails to converge after generating rapidly amplified oscillatory solutions. It is concluded that ISS scheme can be useful in improving the numerical stability of FSI analysis for ACM and BCM solid rocket motor simulations, which is not successfully obtained with CSS scheme.
하악후퇴증 환자에서 골신장술과 하악지 시상분할 골절단술의 술 후 안정성에 관한 비교 연구
유명수,이지호,김명진,You, Myung-Su,Lee, Jee-Ho,Kim, Myung-Jin 대한악안면성형재건외과학회 2012 Maxillofacial Plastic Reconstructive Surgery Vol.34 No.2
Purpose: In general, the surgical treatment for mandibular retrognathism is represented by two methods, distraction osteogenesis (DO) and mandibular osteotomy surgery. The DO is mostly preferred when the degree of advancement of mandible is large. However, the postoperative stability of mandibular advancement using DO have not been actively investigated. Therefore, in the present study we have compared the postoperative stability between DO and bilateral sagittal split ramus osteotomy (BSSRO) in mandibular retrognathism. Methods: Seven patients who had been treated by DO and thirteen patients with BSSRO were included in this study. Serial lateral cephalograms were analyzed by manual tracing and the amount of the mandibular elongation was measured. To evaluate the postoperative stability, positional changes of the condylar position and B point were analyzed. Results: Mean amount of mandibular advancement was $6.51{\pm}3.57mm$ for BSSRO group and $12.43{\pm}4.35mm$ for DO group, respectively. There was no significant difference in age between the two groups (P>0.05). Mean follow up periods were 10.77 months for BSSRO group and 11.28 months for DO group, respectively. After mandibular advancement, mean positional changes in the condyle were $0.56{\pm}1.43mm$ horizontally and $0.72{\pm}1.61mm$ vertically for BSSRO group and $0.53{\pm}1.56mm$ horizontally and $0.56{\pm}1.75mm$ vertically for DO group, respectively. Mean change of distance from B point to Y-axis was $-1.76{\pm}0.83mm$ for BSSRO group and $-2.14{\pm}1.82mm$ for DO group, respectively. According to the condylar position and B point, there were no significant differences in postoperative stability between the two groups (P>0.05). Conclusion: There was no significant difference in postoperative stability between DO and BSSRO group according to condylar position and B point. Based on the results of the present study, it is hypothesized that DO would be a good treatment choice for severe mandibular retrognathism because DO could achieve more mandibular advancement and concurrent soft tissue elongation.