• 한국가시화정보학회지
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• 제18권3호
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• pp.96-102
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• 2020

Oral cancer surgery changes the morphologic characteristics of the human upper airway. These changes can affect the flow patterns. In this study, computational fluid dynamics (CFD) simulations with transient solver were performed to numerically investigate the air flows in the human upper airways depending oral cancer surgery. 3D reconstructed models were obtained from 2D CT images of one patient. For the boundary condition, the realistic breathing cycle of human was applied. The hydraulic diameters of cross-sections for post-surgical model are changed greatly along streamwise direction, so these variations can cause higher wall shear stress and flow disturbance compared to pre-surgical model. The recirculation flows observed in the protruding region result in the relatively large pressure drop. These results can be helpful to understand the flow variations after resection surgery of oral cancer.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제40권
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• pp.4.1-4.4
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• 2018

Background: Along with the advances in technology of three-dimensional (3D) printer, it became a possible to make more precise patient-specific 3D model in the various fields including oral and maxillofacial surgery. When creating 3D models of the mandible and maxilla, it is easier to make a single unit with a fused temporomandibular joint, though this results in poor operability of the model. However, while models created with a separate mandible and maxilla have operability, it can be difficult to fully restore the position of the condylar after simulation. The purpose of this study is to introduce and asses the novel condylar repositioning method in 3D model preoperational simulation. Methods: Our novel condylar repositioning method is simple to apply two irregularities in 3D models. Three oral surgeons measured and evaluated one linear distance and two angles in 3D models. Results: This study included two patients who underwent sagittal split ramus osteotomy (SSRO) and two benign tumor patients who underwent segmental mandibulectomy and immediate reconstruction. For each SSRO case, the mandibular condyles were designed to be convex and the glenoid cavities were designed to be concave. For the benign tumor cases, the margins on the resection side, including the joint portions, were designed to be convex, and the resection margin was designed to be concave. The distance from the mandibular ramus to the tip of the maxillary canine, the angle created by joining the inferior edge of the orbit to the tip of the maxillary canine and the ramus, the angle created by the lines from the base of the mentum to the endpoint of the condyle, and the angle between the most lateral point of the condyle and the most medial point of the condyle were measured before and after simulations. Near-complete matches were observed for all items measured before and after model simulations of surgery in all jaw deformity and reconstruction cases. Conclusions: We demonstrated that 3D models manufactured using our method can be applied to simulations and fully restore the position of the condyle without the need for special devices.

• Journal of International Society for Simulation Surgery
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• 제4권1호
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• pp.13-16
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• 2017

Fibular free flap reconstruction is the flap of the choice in long-span mandibular bone reconstruction. The most common disadvantage of the fibular flap is short bone height to install dental implant. Double barrel fibular flap has been tried, however, bulky flap in the oral cavity hinder its use. Titanium reconstruction plate has been used simultaneously with the free fibular flap to stabilize occlusion and to fix the fibular flap. In this study, titanium reconstruction plate was fixed in the lower border of the mandible and the fibular free flap was fixed in the superior border of the titanium plate to improve implant-crown ratio. This new technique improved the longevity of the dental prosthodontics with dental implants.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제37권
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• pp.44.1-44.6
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• 2015

Background: The present study introduces the design and fabrication of a simple surgical guide with which to perform genioplasty. Methods: A three-dimensional reconstruction of the patient's cranio-maxilla region was built, with a dentofacial skeletal model, then derived from CT DICOM data. A surgical simulation was performed on the maxilla and mandible, using three-dimensional cephalometry. We then simulated a full genioplasty, in silico, using the three-dimensional (3D) model of the mandible, according to the final surgical treatment plan. The simulation allowed us to design a surgical guide for genioplasty, which was then computer-rendered and 3D-printed. The manufactured surgical device was ultimately used in an actual genioplasty to guide the osteotomy and to move the cut bone segment to the intended location. Results: We successfully performed the osteotomy, as planned during a genioplasty, using the computer-aided design and computer-aided manufacturing (CAD/CAM) surgical guide that we initially designed and tested using simulated surgery. Conclusions: The surgical guide that we developed proved to be a simple and practical tool with which to assist the surgeon in accurately cutting and removing bone segments, during a genioplasty surgery, as preoperatively planned during 3D surgical simulations.

• Communications for Statistical Applications and Methods
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• 제24권3호
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• pp.271-290
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• 2017

We study a bivariate response regression model with arbitrary marginal distributions and joint distributions using Frank and Clayton's families of copulas. The proposed model is used for fitting dependent bivariate data with explanatory variables using the log-odd log-logistic Weibull distribution. We consider likelihood inferential procedures based on constrained parameters. For different parameter settings and sample sizes, various simulation studies are performed and compared to the performance of the bivariate odd-log-logistic-Weibull regression model. Sensitivity analysis methods (such as local and total influence) are investigated under three perturbation schemes. The methodology is illustrated in a study to assess changes on schoolchildren's oral health-related quality of life (OHRQoL) in a follow-up exam after three years and to evaluate the impact of caries incidence on the OHRQoL of adolescents.

• Journal of International Society for Simulation Surgery
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• 제2권1호
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• pp.1-6
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• 2015

Purpose Bisphophonate-related osteonecrosis of the jaw (BRONJ) is an emerging problem. Extensive osteonecrosis of the jaw needs free flap reconstruction. Free fibular flap is the most useful flap for maxilla-mandibular hard and soft tissue reconstruction. The advantages of fibular free flap are simultaneous soft and hard tissue reconstruction and placing implant in reconstructed mandible and maxilla. In this study, four consecutive BRONJ patients who underwent fibula free flap reconstruction using simulation surgery were reviewed. Materials and Methods Four BRONJ patients who underwent free fibula reconstruction between May 2006 and September 2014 were included in this study. Male to female ratio was 1:3 and average age was 67.3 years old (62-70). All patients need mandibular bone reconstruction. Three patients suffered from osteoporosis and one male patient had multiple myeloma. Postoperative flap survival, functional reconstruction, esthetic results, food taking were evaluated. Results Three osseous flaps and one osteocutaneous flap were used. All the fibular flaps were survived and patients were recovered without complications. Oro-cutaneous fistula was resolved after operation. All patients were satisfied with the esthetic results. Patients reported improved solid food intake after operation with partial denture. One fully edentulous patient had semi-fluid diet after operation. Conclusion Treatment of the BRONJ is difficult due to lack of standard protocol. Fibular free flap using simulation surgery is the workhorse flap for mandibular hard and soft tissue reconstruction, especially in stage III BRONJ patient. In this study, functional and esthetic results were successful in all patients. Normal diet was possible with partial dentures.

• 대한기계학회논문집 C: 기술과 교육
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• 제2권2호
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• pp.73-80
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• 2014

상기도 내의 약물 전달을 알아보기 위하여 구강 호흡 시 공기유동에 대한 수치해석을 수행하였다. 상기도는 구강과 후두, 기관과 기관지로 구성되어 있다. 정밀 촬영한 CT 데이터로부터 의료영상 소프트웨어(Mimics)를 이용한 구분(segmentation)과 세심한 표면처리를 통하여 해부학적으로 정확한 모델을 만들 수 있었다. 이 3차원 컴퓨터 모델을 이용하여, 구강에서 기관지의 2번째 분지까지 이르는 유로의 수치 모델을 제작하였다. 수치해석은 상용 소프트웨어인 ANSYS/Fluent를 이용하여 계산하였다. 본 연구에 사용된 모델은 노즐이 부착되지 않은 상태에서 초당 250 mL를 흡입하는 정상 구강호흡 모델과 입구에 각각 20 mL/s, 40 mL/s, 60 mL/s의 유량을 갖는 노즐을 장착한 모델을 사용하였다. 전산 유동가시화 결과로부터, 노즐의 유량을 증가시킬수록 선회류의 발생 정도가 증가하여 구강 내 약물의 잔류 량은 증가하지만, 기관/기관지에 약물 도표는 균일하게 나타났다.

• 안보군사학연구
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• 통권3호
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• pp.243-263
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• 2005

The purpose of present study is to applied center assess method to Military General's Promotion System. This study aim to examine assessment center method based on core competency model will be applied to Military General's Promotion System and Human Resource Management. This study propose that Military General's core competency model based on job analysis to identify competency of Army, Navy, Air Force's Generals and to identify the consequences and performances of assess center method. This study propose that assess center method applied to Military General's Promotion System have many kinds. Facilitated Simulation methods were Planning and Analysis /Oral Presentation, Presentation management Coaching, customer /Peer lnteraction. Non-facilitated Simulation methods were In-Basket game, Leaderless Group Discussion, role playing. And this study propose that Military General's assessment center method based on core competency model will be effective in Military field.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제39권
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• pp.16.1-16.6
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• 2017

Background: Mandibular reconstruction is performed after segmental mandibulectomy, and precise repositioning of the condylar head in the temporomandibular fossa is essential for maintaining preoperative occlusion. Methods: In cases without involvement of soft tissue around the mandibular bone, the autopolymer resin in a soft state is pressed against the lower border of the mandible and buccal and lingual sides of the 3D model on the excised side. After hardening, it is shaved with a carbide bar to make the proximal and distal parts parallel to the resected surface in order to determine the direction of mandibular resection. On the other hand, in cases that require resection of soft tissue around the mandible such as cases of a malignant tumor, right and left mandibular rami of the 3D model are connected with the autopolymer resin to keep the preoperative position between proximal and distal segments before surgical simulation. The device is made to fit the lower border of the anterior mandible and the posterior border of the mandibular ramus. The device has a U-shaped handle so that adaptation of the device will not interfere with the soft tissue to be removed and has holes to be fixed on the mandible with screws. Results: We successfully performed the planned accurate segmental mandibulectomy and the precise repositioning of the condylar head by the device. Conclusions: The present technique and device that we developed proved to be simple and useful for restoring the preoperative condylar head positioning in the temporomandibular fossa and the precise resection of the mandible.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권4호
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• pp.366-375
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• 2001

Bone shaving for surgical correction is general method in facial asymmetrical patient with fibrous dysplasia. Therefore, decision of bone shaving amount on the preoperative planning is very difficult for improvement of ideal occlusal relationship and harmonious face. Preoperative planning of facial asymmetry with fibrous dysplasia is generally confirmed by the simulation surgery based on evaluation of clinical examination, radiographic analysis and analysis of facial study model. However, the accurate postoperative results can not be predicted by this method. By using the computed tomography based RP(rapid prototyping) model, simulation of facial skeleton can be duplicated and 3-dimensional simmulation surgery can be perfomed. After fabrication of postoperative study model by preoperactive bone shaving, preoperative and postoperactive surgical index was made by omnivaccum and clear acrylic resin. Amount of bone shaving is confirmed by superimposition of surgical index at the operation. We performed the surgical correction of facial asymmetry patients with fibrous dysplasia using surgical index and prototyping model and obtained the favorable results.