• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.253-258
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• 2016

The development of translucent zirconia enabled clinicians to choose a monolithic zirconia crown as one treatment modality in the posterior dentition. Careful occlusal adjustments are recommended for monolithic zirconia crowns because grinding zirconia inevitably causes phase transformation, which may deteriorate mechanical properties. intraoral scanners enable the clinician to scan and superimpose a complete tooth structure before preparation onto the prepared abutment. This technique helps to reproduce the original tooth form and occlusion of the patient. In this case report, prostheses were fabricated for patients with cracked or fractured tooth by applying intraoral scanner, Computer aided design-computer aided manufacturing (CAD-CAM) and monolithic zirconia crown to reproduce the occlusion of original tooth and to minimize occlusal adjustment. The clinical results were satisfactory in both esthetic and functional aspects.

• The Journal of Advanced Prosthodontics
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• v.10 no.5
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• pp.335-339
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• 2018

PURPOSE. The purpose of the present study was to compare scanning trueness and precision between an abutment impression and a stone model according to dental computer-aided design/computer-aided manufacturing (CAD/CAM) evaluation standards. MATERIALS AND METHODS. To evaluate trueness, the abutment impression and stone model were scanned to obtain the first 3-dimensional (3-D) stereolithography (STL) file. Next, the abutment impression or stone model was removed from the scanner and re-fixed on the table; scanning was then repeated so that 11 files were obtained for each scan type. To evaluate precision, the abutment impression or stone model was scanned to obtain the first 3-D STL file. Without moving it, scanning was performed 10 more times, so that 11 files were obtained for each scan type. By superimposing the first scanned STL file onto the other STL files one by one, 10 color-difference maps and reports were obtained; i.e., 10 experimental scans per type. The independent t-test was used to compare root mean square (RMS) data between the groups (${\alpha}=.05$). RESULTS. The $RMS{\pm}SD$ values of scanning trueness of the abutment impression and stone model were $22.4{\pm}4.4$ and $17.4{\pm}3.5{\mu}m$, respectively (P<.012). The $RMS{\pm}SD$ values of scanning precision of the abutment impression and stone model were $16.4{\pm}2.9$ and $14.6{\pm}1.6{\mu}m$, respectively (P=.108). CONCLUSION. There was a significant difference in scanning trueness between the abutment impression and stone model, as evaluated according to dental CAD/CAM standards. However, all scans showed high trueness and precision.

• The Journal of Advanced Prosthodontics
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• v.11 no.2
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• pp.128-137
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• 2019

PURPOSE. The aim of this study was to compare the effect of different finishing and polishing techniques on water absorption, water solubility, and microhardness of ceramic or glass-polymer based computer-aided design and computer-aided manufacturing (CAD/CAM) materials following thermocycling. MATERIALS AND METHODS. 150 disc-shaped specimens were prepared from three different hybrid materials and divided into five subgroups according to the applied surface polishing techniques. All specimens were subjected up to #4000 grit SiC paper grinding. No additional polishing has been done to the control group (Group I). Other polishing procedures were as follows: Group II: two-stage diamond impregnated polishing discs; Group III: yellow colored rubber based silicone discs; Group IV: diamond polishing paste; and Group V: Aluminum oxide polishing discs. Subsequently, 5000-cycles of thermocycling were applied. The analyses were conducted after 24 hours, 7 days, and 30 days of water immersion. Water absorption and water solubility results were analyzed by two-way ANOVA and Tukey post-hoc tests. Besides, microhardness data were compared by Kruskal-Wallis and MannWhitney U tests (P<.05). RESULTS. Surface polishing procedures had significant effects on water absorption and solubility and surface microhardness of resin ceramics (P<.05). Group IV exhibited the lowest water absorption and the highest microhardness values (P<.05). Immersion periods had no effect on the microhardness of hybrid ceramic materials (P>.05). CONCLUSION. Surface finishing and polishing procedures might negatively affect physical properties of hybrid ceramic materials. Nevertheless, immersion periods do not affect the microhardness of the materials. Final polishing by using diamond polishing paste can be recommended for all CAD/CAM materials.

• The Journal of Advanced Prosthodontics
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• v.12 no.6
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• pp.329-337
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• 2020

PURPOSE. To verify the influence of computer-aided design/computer-aided manufacturing (CAD/CAM) implant-supported prostheses manufactured with cobalt-chromium (Co-Cr) and zirconia (Zr), and whether ceramic application, spark erosion, and simulation of masticatory cycles modify biomechanical parameters (marginal fit, screw-loosening torque, and strain) on the implant-supported system. MATERIALS AND METHODS. Ten full-arch fixed frameworks were manufactured by a CAD/CAM milling system with Co-Cr and Zr (n=5/group). The marginal fit between the abutment and frameworks was measured as stated by single-screw test. Screw-loosening torque evaluated screw stability, and strain analysis was explored on the implant-supported system. All analyses were performed at 3 distinct times: after framework manufacturing; after ceramic application in both materials' frameworks; and after the spark erosion in Co-Cr frameworks. Afterward, stability analysis was re-evaluated after 106 mechanical cycles (2 Hz/150-N) for both materials. Statistical analyses were performed by Kruskal-Wallis and Dunn tests (α=.05). RESULTS. No difference between the two materials was found for marginal fit, screwloosening torque, and strain after framework manufacturing (P>.05). Ceramic application did not affect the variables (P>.05). Spark erosion optimized marginal fit and strain medians for Co-Cr frameworks (P<.05). Screw-loosening torque was significantly reduced by masticatory simulation (P<.05) regardless of the framework materials. CONCLUSION. Co-Cr and Zr frameworks presented similar biomechanical behavior. Ceramic application had no effect on the biomechanical behavior of either material. Spark erosion was an effective technique to improve Co-Cr biomechanical behavior on the implant-supported system. Screw-loosening torque was reduced for both materials after masticatory simulation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.104-107
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• 2002

Direct Metal Manufacturing (DMM) is a new additive process that aims to take die making and metalworking in an entirely new direction. It is the blending of five common technologies : lasers, computer-aided design (CAD), computer-aided manufacturing (CAM), sensors and powder metallurgy. The resulting process creates parts by focusing an industrial laser beam onto a tool-steel work piece or platform to create a molten pool of metal. A small stream of powdered tool-steel metal is then injected into the melt pool to increase the size of the molten pool. By moving the laser beam back and forth, under CNC control, and tracing out a pattern determined by a computerized CAD design, the solid metal part is built line-by-line, one layer at a time. DMM produces improved material properties in less time and at a lower cast than is possible with traditional fabrication.

• Journal of Power System Engineering
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• v.15 no.4
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• pp.60-64
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• 2011

Computer-aided engineering (CAE) is the broad usage of computer software to aid in engineering tasks. It includes computer-aided design (CAD), computer-aided analysis (CAA), computer-integrated manufacturing (CIM), computer-aided manufacturing (CAM), material requirements planning (MRP), and computer-aided planning (CAP). In this study, the stress of mold analyzed using CAE technique. Punch loads were same difference between 0.5 % and 1.0 % of clearance, but punch load was decreased according to increasing of clearance. Punch load of pre-piercing process worked a little smaller than piercing process. Therefore, the hole of fine blanking process is also more efficient to manufacture the true size after pre-piercing.

• Korean Institute of Interior Design Journal
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• no.9
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• pp.24-29
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• 1996

The objectives of this study is to create an environment which students could apply effectively through focused on the innovative methods of education and CAD course contents. The facts which were able to figure out from this study were as follows ; 1. After the analysis of the CAD course contents of the american universities, their common contents were in order of introduce to Computer Aided Drafting and design with Auto CAD/ provide fundamental knowledge of the application for use in design/ examine and how this effects 2 D image and model creation/ CAD as a design tool . Over all trend of CAD course contents of interior design program in american university is moving toward utilizing CAD as a design tool. 2. On the other hand, common contents of our local universities were simply introducing CAD. It means that our course contents are more methodological and theoreatical . And american university's program is focused on problem solving solution as a design tool.

• Journal of the Korean Society for Precision Engineering
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• v.3 no.4
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• pp.23-29
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• 1986

CAD라 함은 computer Aided Design의 약자로서, 종종 컴퓨터 지원설계로 번역되고 있다. 그리고, CAM도 computer Aided Manufacturing의 약자로서 컴퓨터 지원제조로 번역된다. 컴퓨터가 실용화되고 설계에의 이용이 가능해졌을 당시는 설계의 자동화(DA : Design Automation)에 대한 기대가 컸다. 그러나 현실로는, 설계자가 설계하는데 있어서 컴퓨터와 주변장치들을 가까이 두고 도구로 이용하게 되었으나, 그것은 주로 제한된 비교적 단순한 제품의자동설계로서, DA의 발전은 예상외로 제자리 걸음을 하고 있었다. 인간을 대신하여 컴퓨터에 설계를 시킨다는 것이 얼마나 어렵다는 것, 특히, 그와같은 Software 개발이 어럽다는 것을 인식하게 되었다. 그래서 <생각하는 일>과 <창조하는 일>과 같이 본래 인간의 본질적인 기능 에 속하는 것을 인간(설계자) 이 하고, <설계하는 일> <제도하는 일> 과 같은 기계적 인 일을 컴퓨터에 시키는 분업이 생각하게 되었다. 이것이 컴퓨터 지원설계(CAD)인 것이다. CAC에 있어서, 설계의 주역은 어디까지나 인간(설계자)에 있으며, 컴퓨터는 설계자의 기계적(비인간적)인 일을 도와주는 도구인 것이다. 이와같이 설계에 있어서 컴퓨터의 위치가 정의된다.

• Journal of Korean Dental Science
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• v.15 no.2
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• pp.166-171
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• 2022

This case report describes a dynamic digital esthetic rehabilitation procedure that integrates a new three-dimensional augmented reality (3D-AR) technique to treat a patient with multiple missing anterior teeth. The prostheses were designed using computer-aided design (CAD) software and virtually trialed using static and dynamic visualization methods. In the static method, the prostheses were visualized by integrating the CAD model with a 3D face scan of the patient. For the dynamic method, the 3D-AR application was used for real-time tracking and projection of the CAD prostheses in the patient's mouth. Results of a quick survey on patient satisfaction with the two visualization methods showed that the patient felt more satisfied with the dynamic visualization method because it allowed him to observe the prostheses directly on his face and be more proactive in the treatment process.

• 한국기계연구소 소보
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• s.17
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• pp.69-74
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• 1987

This paper introduces a case-building algorithm which can determine automatically a desired design case by categorizing known-variables and unknown-variables among design variables. Common CAD programs use a case-selection technique, where a programmer sets initially a few of design cases and then users can only choose one of the given cases. The case-building technique is a powerful tool for the expert computer-aided design technology.