• Composites Research
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• v.12 no.5
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• pp.98-109
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• 1999

An investigation has been performed to develop a nonlinear finire element method for the analysis of the long-term behavior of an artificial hip joint. The three dimensional multi-layered brick element is used to analyze the design performances of hip prodtheses with various materials and the thick laminated composite hip prostheses with various layup sequences. The used element can accommodate the varying material properties of the element and allow the ply-drop-off along the eleement edge. The nonlinear finite element analysis program has been verified by the comparison with the exact solution of the bean problem subjected to uniaxial loading. By using the program, the density changes and strength ratios of artificial hip joint are calculated according to the hip prosthesis materials and the layers of composite hip prosthesis. The numerical results are easily applied to evaluate design performances of a hip prosthesis, and decrease the difficulty and time of hip prosthesis design.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.3
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• pp.276-282
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• 2022

Close communication between clinicians and dental technicians is an important factor in providing successful prostheses. The exchange of opinions with laboratories has mainly been in the form of written prescriptions and a photos, but it has been reported that information transmission may be limited. Currently, as digital technology-based prosthesis fabrication is common, 3D image objects can be stored on the web and can be easily viewed through a mobile web browser. In this article, we introduce cases where the design of the prosthesis was improved by designing the prosthesis using CAD software and reviewing the prosthesis designed with the clinical side through a web viewer. Through this protocol, it was possible to improve the occlusal surface and crown contour, the opposing teeth condition, the size of the gingival embrasure, and the shape of pontic. The process of sharing, discussing, and modifying the prosthesis design with the clinician and technician through a web viewer contributes to reflecting the diversity of oral conditions and individualized needs, thereby helping to make functional and esthetic prostheses.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.3
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• pp.288-295
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• 2019

Passive fit of prosthesis is an essential property of implant supported prosthesis for long term success and minimization of complications. And the property is determined mostly by fabrication procedure. There were limitations of extensive implant prosthesis because conventional casting method generate contraction error of long span prosthesis. However, Computer-aided design/Computer-aided manufacturing (CAD/CAM) technology of 3D printing and milling metal framework can overcome those limitations. This case is a full mouth rehabilitation using extensive implant fixed prosthesis. Removable interim prosthesis was made for esthetic, functional evaluation and a guide for implant insertion. After the insertion, implant fixed interim prosthesis was delivered. After additional evaluation and adjustment, final prosthesis was designed with CAD, the fabricated with CAM. Milling technique was used for anterior screw type implant superstructure and 3D printing technique was used for the anterior and posterior implant copings. Fit of the final restoration was favorable. The practitioner and patient were both esthetically and functionally satisfied with the final result.

• 대한치과보철학회:학술대회논문집
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• 1992.05a
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• pp.10-11
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• 1992

상악골이 부분적으로 결손된 환자의 증가와, 수술 후 수명의 연장으로 좀 더 확실한 보철물이 요구되고 있다. 본 증례에서는 종양으로 인해 상악골의 Leoisection을 시행한 2명의 환자에 대하여 obturator를 제작, 창착하여 발표, 심미, 기능 및 심리적인 개선이 이루어졌다. 그러나 악골 자체의 부분의 소실로 외치의 지지 및 유지등에 한계성이 있으므로, 장래의 Hemimaxillectomy가 시행된 악궁에 대한 의치의 설계에 관한 더 많은 연구가 진행되어야 하겠다.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.3
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• pp.227-233
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• 2023

Tardive dyskinesia is an involuntary neurological movement disorder caused by long-term use of dopamine receptor-blocking drugs leading to dental implications like uncontrolled gnashing and grinding of teeth which in turn imperil the oral rehabilitation procedures as the excessive load increases the risk of prosthesis fracture. A 40-year male with a medical history of tardive dyskinesia visited the hospital to receive oral rehabilitation for missing maxillary anterior teeth. After the oral examination, tooth preparation was done on teeth 13, 15, and 23. After that silicon impression was made and the gypsum cast was digitalized using a desktop scanner and an interim prosthesis was fabricated by milling a resin block. During the try-in, the occlusal one-third of the interim prosthesis was trimmed, and an auto-polymerizing acrylic resin was applied on the occlusal surfaces and inserted in the patient's mouth. Then, the functionally generated path (FGP) of occluding surfaces of opposing arches was traced on the resin surface. When the resin was hardened, the modified interim prosthesis was removed and digitized using an intraoral scanner. The scan image was used in designing the occlusal morphology of definitive prosthesis by modifying the design of the interim prosthesis using the dual scan method. Lastly, a monolithic zirconia prosthesis was fabricated by milling a zirconia block. The definitive prosthesis was delivered reflecting the patient's occlusal scheme. This case report shows that the FGP technique with the dual scan method can help in fabricating fixed prosthesis with harmonious occlusion in a tardive dyskinesia patient.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.3
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• pp.246-251
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• 2014

In case of prosthesis fabrication by CAD/CAM, location, area and contour of occlusal contacts can be adjusted so more functional occlusion can be acquired. Also, errors in a manufacturing process is reduced compared to cast metal prostheses and porcelain fused metal prostheses fabricated by conventional methods such as casting and porcelain build up. Therefore, prostheses by CAD/CAM show superior occlusion accuracy. Recently, virtual articulator function has been introduced to CAD/CAM system, which reproduces mandibular movement against maxilla. Thus, it is possible to consider occlusal interference in anterior/lateral movement as well as closing movement. There have been many studies on the marginal and internal fit of prostheses using zirconia but the occlusal fit of zirconia crown fabricated by CAD/CAM has not been researched as much. In this case report, 7 zirconia crowns were designed and fabricated by CAD/CAM for total 5 patients. The models of zirconia crowns before and after occlusal adjustment during intraoral try-in were scanned for occlusal contacts, which were compared to evaluate accuracy of prostheses and understand patterns of occlusal adjustment. Most of the occlusal adjustments were done on functional cusps and slopes of zirconia crown, and the magnitude of occlusal adjustment ranged from $15{\mu}m$ to $60{\mu}m$. In the zirconia crown fabricated with CAD/CAM systems, the occlusal adjustment is a necessary procedure, so additional procedures will be needed for compensating reduced mechanical properties.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.2
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• pp.164-170
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• 2017

When restoring their anterior dentition, patients become more demanding on esthetics compared to posterior region during treatment planning phase. Digital Smile Design (DSD) procedure is performed in presentation software and digital photographs. This can widen diagnostic visualization and aid in transferring information between clinician, patient, and technician. This case presented is that of patient with dissatisfaction of his anterior old restoration. Retreatment procedures were carried out in two different manners: (1) using DSD protocol for diagnosis, smile simulation, communication and fabricating interim and definitive prosthesis by totally digitized workflow. (2) Using diagnostic wax-up for smile design and fabricating restorations by conventional workflow. Comparing two methods, DSD was easier to communicate between the dental team than the diagnostic wax-up method. But the final result obtained failed to meet total esthetic factors. Therefore, to obtain predictable esthetic results, more advanced design tool would be needed, including consideration of various esthetic factors besides successful communications.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.598-600
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• 1999

본 논문은 수공으로 이루어지는 치과 치료 및 보철물 제작을 3차원 컴퓨터 모델링을 하여 좀 더 정확하고 빠른 시간에 처리할 수 있는 시스템을 소개한다. 이 시스템은 기존 2차원 기반이 아닌 3차원 기반으로 설계되었으며, 구강의 석고 모형을 3차원으로 컴퓨터에 모델링한 후, 모델링 정보로부터 능선(ridge), 교두(crusp), 피트(pit), 열구(fissure), 변연(margin) 등과 같은 치아 특성 정보추출과 교합면 생성을 통하여 보철물, 예를 들어 Conus 내관과 외관을 제작한다. 해부학적으로 무수히 많은 변수를 갖고 있는 구강 구조에 대해 본 논문에서는 이들 일련의 과정에서 요구되는 컴퓨터 모델링의 주요 기술들을 제시한다.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.1
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• pp.97-106
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• 2021

Dental implants should be placed at ideal sites for implant-supported restorations. For a patient with insufficient residual ridge, mouth preparation including surgical intervention can be indicated to establish a soft and hard tissue environment favorable for a definitive prosthesis. Prosthodontic design based on computer-guided surgery and computer-aided design-computer-aided manufacturing (CAD-CAM) provides a visual blueprint allowing a clinician to assess the necessity of such a surgical intervention beforehand. In this case, a definitive restoration was planned and made via a CAD-CAM system according to the patient's oral status before treatment, simulated surgical interventions and serial provisional restorations. Based on the planning, a guided template was made and the implants were installed with bone augmentation using the template. Customized abutments, the first and the second provisional restorations were designed and fabricated by CAD-CAM. The definitive restorations were digitally made following the shape of the second provisional prostheses, which were confirmed in the patient's mouth. The patient was satisfied with the masticatory, phonetic and aesthetic functions of these definitive prostheses.

• 대한치과보철학회:학술대회논문집
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• 1998.11a
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• pp.52-52
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• 1998