• Journal of dental hygiene science
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• v.14 no.3
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• pp.349-355
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• 2014

The purpose of this study was to evaluate marginal gap of fixed dental prostheses (FDPs) fabricated by soft metal material with using dental computer aided design/computer aided manufacturing (CAD/CAM) system and to compare gap of its by a conventional method. Ten same cases of study models were manufactured and scanned for digital models fabricating. Ten FDPs were fabricated by soft metal material using dental CAD/CAM (SMB group). Then, ten FDPs were fabricated by cast metal using lost wax technique and casting method (LWC group). Marginal gap was measured by silicone replica technique. Gap was measured by digital microscope (${\times}160$). Mann-Whitney test for statistical analysis was executed (${\alpha}=0.05$). The mean (standard deviations) of marginal gap was $76.5{\mu}m$ (35.2) for the SMB group, and $82.9{\mu}m$ (22.1) for the LWC group. Statistically significant differences were not found between SMB and LWC. As results, FDPs fabricated by soft metal material were clinically acceptable range.

• Journal of Powder Materials
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• v.25 no.6
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• pp.475-481
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• 2018

Selective laser melting (SLM), a type of additive manufacturing (AM) technology, leads a global manufacturing trend by enabling the design of geometrically complex products with topology optimization for optimized performance. Using this method, three-dimensional (3D) computer-aided design (CAD) data components can be built up directly in a layer-by-layer fashion using a high-energy laser beam for the selective melting and rapid solidification of thin layers of metallic powders. Although there are considerable expectations that this novel process will overcome many traditional manufacturing process limits, some issues still exist in applying the SLM process to diverse metallic materials, particularly regarding the formation of porosity. This is a major processing-induced phenomenon, and frequently observed in almost all SLM-processed metallic components. In this study, we investigate the mechanical anisotropy of SLM-produced 316L stainless steel based on microstructural factors and highly-oriented porosity. Tensile tests are performed to investigate the microstructure and porosity effects on mechanical anisotropy in terms of both strength and ductility.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4405-4410
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• 2012

This research aims to do heat transfer analysis on multi-functional dough conditioner. The dough conditioner is a key bakery machine for the maturation of dough which is raw material of bakery and also it's amount of used has been increased. Solidworks which is one of automatic design programs is applied to design in order to manufacture the multi-functional dough conditioner, and ANSYS which is a three dimensional finite element analysis code is used for the heat transfer analysis. Inside temperatures and heat fluxes are obtained as the results of heat transfer analysis and the results are contributed significantly in manufacturing the multi-functional dough conditioner.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.4
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• pp.444-450
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• 2017

Prosthetic decision-making is complex because of various factors, and involves a combination of the individual dentist's interpretation of the objective clinical data and his or her interaction with the patient. Increasing therapeutic options and emerging outcome data demand the constant re-evaluation of our decision-making process. In this case, fixed prosthetic restorations were selected as a treatment method to reconstruct the occlusal plane of a patient with disharmonious occlusal plane. And the occlusal plane was re-established by establishing a treatment plan through diagnostic wax-up. Provisional restorations obtained by continuous re-evaluation for a sufficient period of time was replicated to definitive restorations using CAD/CAM technology. The results were satisfactory when they were observed through clinical follow-up for 3 months after the end of treatment.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.25 no.2
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• pp.79-87
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• 2016

Single visit monolithic restoration can be proceed with digital workflow which consist of intraoral scanning, dental CAD(computer aided design) and restoration milling with CAM(Computer aided manufacturing). While zirconia has more than 900MPa of flexural strength compared with 400MPa for lithium disilicate, shortened fabricating time of lithium disilicate is considered to be a better choice for fabricating single visit full contour monolithic restoration. However, new zirconia materials which are TZI C(Dentsply Sirona) and LUXEN Enamel(Dental Max), new induction heating method of sintering furnace, and new sintering protocols for MoSi2 heating elements sintering furnace offer significantly reduction of full contour monolithic zirconia restoration fabrication time with greater translucency. These new developments lead single visit zirconia restoration in reality.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.4
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• pp.469-477
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• 2021

For successful restoration of maxillary anterior implants, both pink esthetics and white esthetics must be satisfied. For pink esthetic part, the role of appropriate provisional prosthesis restoration is important, and for white esthetic part, the color and shape of the definitive prosthesis is important. Multilayer zirconia can be used for natural tooth appearance due to the higher transparency of the incisal area compared to the conventional monolithic zirconia. Therefore, in this case, white esthetic part was achieved through multilayer zirconia after recovering function and esthetics through appropriate provisional prosthesis in a patient who lost the maxillary anterior teeth.

• The Journal of the Korea Contents Association
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• v.21 no.5
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• pp.996-1003
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• 2021

The purpose of this study is to evaluate the reliability of repeated measurements of several dental scanners. Blue-lighted scanners, white-light scanners and optical-type scanners are used in the study of repeatability in this study. The measurement results were calculated as root mean square (RMS) and the significance level was confirmed by applying the 1-way ANOVA statistical technique (𝛼=.05). According to the statistical analysis, the scanner with the largest RMS value was Z-opt group (38.2 ㎛. Next, D-white was 35.2 ㎛ and the group with the lowest RMS value was I-blue (34.1 ㎛). The comparison of RMS means between each group was not significant (p>.05). From this result, the blue light had the lowest error in repeatability of dental scanners, but no statistical significance. The conclusion of this study is that the study results are clinically acceptable.

• Journal of Technologic Dentistry
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• v.45 no.4
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• pp.118-123
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• 2023

Purpose: This study proposes measures needed to implement a job-based national practical exam for dental technicians. Methods: For this study, a survey was conducted targeting 244 currently employed individuals. The current national practical test for dental technicians was divided into directions for the job-based practical test, subjects that need improvement among the current practical test subjects, items that need to be reflected in the practical test evaluation for each subject, and subjects that need to be added to the practical test. It comprised ten questions (Cronbach's α=0.801). Results: The following results were obtained. Satisfaction with the current practical test was lower than average. Future improvement should focus on job-based evaluation. The dental ceramic lab technology subject needs to be reorganized urgently, and the tasks that require evaluation for each subject are different. Moreover, if evaluation subjects are added in the future, the introduction of assessment for dental CAD/CAM (computer-aided design/computer-aided manufacturing) subjects was found to be the most urgent. Conclusion: In this study, the most necessary tasks of the current national practical examination for dental technicians were evaluated and the content needed for future reorganization was investigated. Future tests should be expanded to evaluate critical job areas. Furthermore, it is necessary to open new courses in fields such as CAD/CAM, as they are in high demand in the workplace.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.2
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• pp.121-127
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• 2014

Comprehensive prosthetic treatment requires considerations from various points of view. The anterior guidance is important factor in prosthodontic treatment of anterior teeth. Lingual surface contour of anterior restoration is so critical that a small mistake of laboratory or clinical process can cause discomfort of patient and disharmony of entire dentition. There are no guidelines for lingual surface contour that fit all patients. Therefore the lingual surface of provisional restoration is most accurately described as a customized one. The dentist transfers the exact information of anterior guidance that has made through long term provisional restoration to the technician. This case introduce that the duplication technique of CAD/CAM system to reproduce the anterior guidance of provisional restoration. This method can improve satisfaction of both patient and dentist.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.230-238
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• 1999

This paper describes a research work of developing computer-aided design of lead frame, semiconductor, with blanking operation which is very precise for progressive working. Approach to the system is based on the knowledge-based rules. Knowledge for the system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. This system has been written in AutoLISP on the AutoCAD using a personal computer and in I-DEAS Drafting Programming Language on the I-DEAS Master Series Drafting with Workstation, HP9000/715(64) and tool kit on the ESPRIT. Transference of data among AutoCAD, I-DEAS Master Series Drafting, and ESPRIT is accomplished by DXF(drawing exchange format) and IGES(initial graphics exchange specification) methods. This system is composed of six modules, which are input and shape treatment, production feasibility check, strip-layout, die-layout, modelling, and post-processor modules. The system can design process planning and Die design considering several factors and generate NC data automatically according to drawings of die-layout module. As forming process of high precision product and die design system using 2-D geometry recognition are integrated with technology of process planning, die design, and CAE analysis, standardization of die part in die design and process planning of high pression product for semiconductor lead frame is possible to set. Results carried out in each module will provide efficiencies to the designer and the manufacturer of lead frame, semiconductor.