• 한국기계가공학회지
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• 제15권1호
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• pp.116-121
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• 2016

The purpose of this study was to ensure the safety of a scooter frame through a structure and vibration analysis according to the tube thickness and weight of the frame of the electric scooter, which is currently being commercialized. According to the results of this study, the largest displacement value of 0.13238mm appeared in the 3-mm thickness when applying the 100-kg load according to the thickness, and 0.026591mm and 0.019062mm appeared in the 4-mm and 5-mm thicknesses, respectively. The difference between the 4-mm and 5-mm values was 0.007529mm, and it showed low displacement. Thus, the frame of more than 4-mm thickness was considered safe. In addition, the experimental result for the natural frequency from Mode 1 to Mode 6 in the vibration analysis was within 601.88Hz. In the 5-mm frame, the durability regarding the vibration was recognized as the best due to the appearance of the critical frequency (341.03Hz).

• Journal of Yeungnam Medical Science
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• 제41권2호
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• pp.80-85
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• 2024

Background: This study aimed to compare and evaluate the marginal fit of nanocomposite computer-aided design/computer-aided manufacturing (CAD/CAM) inlays. Three types of nanocomposite CAD/CAM blocks (HASEM, VITA Enamic, and Lava Ultimate) were used as materials. Methods: Class II disto-occlusal inlay restorations were prepared on a typodont mandibular right first molar using diamond rotary instruments. The inlays were fabricated using CAD/CAM technology and evaluated using the silicone replica technique to measure marginal gaps at five locations on each inlay. The data were analyzed by two-way analysis of variance and Tukey post hoc tests (α=0.05). Results: There were no significant differences in the marginal gaps based on the type of nanocomposite CAD/CAM inlay used (p=0.209). However, there was a significant difference in the marginal gaps between the measurement regions. The gingival region consistently exhibited a larger marginal gap than the axial and occlusal regions (p<0.001). Conclusion: Within the limitations of this in vitro study, the measurement location significantly influenced the marginal fit of class II disto-occlusal inlay restorations. However, there were no significant differences in the marginal gaps among the different types of CAD/CAM blocks. Furthermore, the overall mean marginal fits of the class II disto-occlusal inlay restorations made with the three types of nanocomposite CAD/CAM blocks were within the clinically acceptable range.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1995년도 춘계학술대회논문집
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• pp.147-154
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• 1995

In this paper, a computer-aided design system for axisymmetric deep drawing process will be described. An approach to the system is based on the knowledge based system. The system has been written in AutoLISP with personal computer. The system is composed of four main modules, such as input , geometrical design, test & rectification and user modification . The system which aids designer provides powerful capabilities for the design of axisymmetric deep drawing process.

• 대한치과보철학회지
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• 제60권1호
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• pp.44-54
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• 2022

다수 치아의 상실 상태로 장시간 지속시 구치부 지지의 부족 및 치아들의 과정출이 발생되어 교합 부조화, 수직고경 상실 및 기능 장애 등의 심각한 문제가 초래된다. 본 증례는 장기간 다수치아 결손으로 인하여 대합치가 정출하면서 교합평면의 붕괴가 일어난 환자의 완전 구강 회복에 관한 증례이다. 상기 환자는 서울대학교 치과병원 치과보철과로 내원한 68세 남환으로 오래된 상악 의치를 빼다가 치아가 함께 발거되었으며, 하악 전치부가 상악 전치부와 강하게 닿아서 불편함을 호소하며 내원하였다. 여러가지 평가를 통해 수직고경을 4 mm 거상하였으며, 무치악부는 진단 및 치료계획시 설계한 최종 보철 수복물 제작을 고려하여 정확한 임플란트 식립을 위해 CAD-CAM (Computer-aided design-computer-aided manufacturing) 기술을 이용한 Computer guided implant surgery를 시행하고, 임플란트 고정성 보철 수복으로 진행하였고, 환자는 저작, 기능 및 심미 모두 큰 개선에 만족하였다.

• 대한치과교정학회지
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• 제54권4호
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• pp.257-263
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• 2024

Objective: Lingual fixed retainers, made from 0.0175-inch 3-strand twisted stainless steel wire (TW) and 0.016 × 0.022-inch straight rectangular wire (RW), are generally used in clinical practice. This study aimed to calculate their accuracy by comparing the discrepancy between computer-aided customized retainers made from these two types of wires. Methods: Eleven orthodontic patients were selected, resulting in 22 maxillary and mandibular three-dimensional printing dental models. Two types of lingual fixed retainers were bonded from canine to canine. To determine the accuracy, five points were chosen for each model, resulting in 110 selected points. The absolute values of the distances on the x-, y-, and z-axes were measured to compare the accuracy of the two types of computer-aided retainers. Results: The accuracy of the two types of retainers did not differ significantly in the x- and z-axes, but only in the y-axis (P < 0.01), where RW-fixed retainers exhibited a slightly but significantly increased distance compared to the TW. Conclusions: Both types of retainers showed high accuracy; however, RW had a slight but statistically significant difference along the y-axis compared with TW. This type of computer-aided design/computer-aided manufacturing bending machine is limited to two dimensions, and the dental arch is curved. Therefore, RW may require slight manual adjustment by the practitioner after manufacturing.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 추계학술대회(한국공작기계학회)
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• pp.330-335
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• 2001

Characteristics of the present world market include demanding and sophisticated customers, requirement of high quality and innovative products, greater product diversity, increasing labour and products costs, availability of diverse alternatives to the customers and smaller batch sizes to satisfy a variety of customer profiles. To fulfil these characteristics, manufacturing companies need to be flexible adaptable, proactive and able to produce variety of products in short time at low cost. The aim of the study is to develop a computer-aided design system for water-gate on AutoCAD R2000 system. The developed system has been written in AutoCAD and VisualLISP with a personal computer, and is composed four modules which are the gate-lifter input module, guide-frame input module, and upgrade module. Based on knowledge-based rules, the system is designed by considering several factors, such as width and height of a water-gate, material, object of product and maximum depth of water.

• Restorative Dentistry and Endodontics
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• 제45권3호
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• pp.27.1-27.9
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• 2020

Apical surgery for a mandibular molar is still challenging for many reasons. This report describes the applications of computer-guided cortical 'bone-window technique' using piezoelectric saws that prevented any nerve damage in performing endodontic microsurgery of a mandibular molar. A 49-year-old woman presented with gumboil on tooth #36 (previously endodontically treated tooth) and was diagnosed with chronic apical abscess. Periapical lesions were confirmed using cone-beam computed tomography (CBCT). Endodontic microsurgery for the mesial and distal roots of tooth #36 was planned. Following the transfer of data of the CBCT images and the scanned cast to an implant surgical planning program, data from both devices were merged. A surgical stent was designed, on the superimposed three-dimensional model, to guide the preparation of a cortical window on the buccal side of tooth #36. Endodontic microsurgery was performed with a printed surgical template. Minimal osteotomy was required and preservation of the buccal cortical plate rendered this endodontic surgery less traumatic. No postoperative complications such as mental nerve damage were reported. Window technique guided by a computer-aided design/computer-aided manufacture based surgical template can be considerably useful in endodontic microsurgery in complicated cases.

• 대한치과보철학회지
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• 제58권1호
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• pp.42-49
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• 2020

무치악 환자에게서 의치의 제작은 통상적이고 전통적인 방법을 따를 경우 최종 의치 장착까지 여러 단계를 거쳐야 하며 이로 인한 환자의 잦은 내원이 불가피하다. 또한 기공 과정 상에서 나타나는 중합수축에 의한 오차나, 의치의 파절이나 분실 시 빠른 재제작의 어려움 등의 단점이 존재하였다. 하지만 최근 치과 분야에서 computer-aided design and computer-aided manufacturing (CAD/CAM) System이 사용되기 시작하였고, 의치 제작에까지 그 영역을 넓히기 시작하였다. CAD/CAM System을 이용하여 의치를 제작하면 첫 번째 내원 시에 인상채득과 악간관계의 기록, 인공치의 선택 등이 동시에 이루어지고 두 번째 내원 시 의치의 장착이 가능하기 때문에 환자의 내원 횟수와 진료시간을 감소시킬 수 있다. 또한 3D-Printing 기술을 이용하기 때문에 중합수축에 의한 기공 오차를 감소시킬 수 있다. 현재 상용화 되어 있는 CAD/CAM System을 사용한 의치로는 DENTCA CAD/CAM denture (DENTCA Inc., Los Angeles, CA, USA)가 있다. 본 증례에서는 상, 하악 완전 무치악 환자에게서 conventional 한 방법과 DENTCA CAD/CAM Denture System을 사용하는 방법을 동시에 사용하여 두 쌍의 총의치로 수복함으로써 발음, 저작, 연하 등의 기능적인 측면뿐만 아니라 심미적인 측면에서도 양호한 결과를 얻었기에 이를 보고하고자 한다.

• 대한치과보철학회지
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• 제60권2호
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• pp.202-210
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• 2022

최근 디지털 치의학의 발달로, Computer-aided design-Computer-aided manufacturing (CAD-CAM)을 이용한 의치 제작이 증가하는 추세이다. CAD 소프트웨어를 통해 디자인된 의치를 제작하는 방식에는 밀링을 이용한 절삭가공방식과 3D 프린팅과 같은 적층가공방식이 있으며, 적층가공방식은 보다 복잡한 구조를 재현하는데 유리하게 사용될 수 있다. 본 증례는 뇌경색으로 인해 신체적 장애를 갖게 된 상·하악 완전무치악 환자에서 제작 기간과 내원 간격을 단축하기 위해 광경화 Stereolithography (SLA) 기반의 3D 프린팅을 이용한 디지털 제작 방식의 양악 총의치 수복 증례이다. 최종인상채득을 위해 기존 임시의치를 디지털 방식으로 복제 및 출력하여 개인트레이로 활용하였고, 부가중합형 실리콘 인상재로 채득한 최종인상체에는 수직고경과 중심위, 상악 전치부의 각도 및 길이에 대한 정보가 포함되었다. 또한 임시의치를 장착하고 촬영한 안면 스캔 데이터를 추가로 획득하여 기공 작업 시 교합평면 결정이나 인공치 배열에 참고할 수 있도록 하였다. 인상체를 3차원 스캔 후 CAD 프로그램을 통해 인공치를 배열하였고, 연마면을 형성하여 의치 디자인을 완성하였다. 시적 의치 및 최종 의치는 FDA 승인을 받은 액체 광경화성 레진을 이용하여 SLA 기반 3D 프린터로 출력하였고, 최종 의치는 적절한 안정과 유지, 지지를 보였으며, 기능적, 심미적으로 만족스러운 결과를 얻을 수 있었다. 최종 의치의 전달까지 3회의 내원 횟수를 필요로 하였으며, 기공시간의 단축으로 내원 간격을 줄임으로써 환자의 만족도를 증진시켰다.

• 한국CDE학회논문집
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• 제8권3호
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• pp.157-166
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• 2003

In this paper, we explain the DMU (digital mockup) system based on the PDM system. Most manufacturing companies are trying to develop a competitive product by increasing the quality, shortening time to market (TIM) and reducing the cost of a product. Some technologies such as SE (System Engineering), CE (Concurrent Engineering), QFD (Quality Function Development), CI (Cost Innovation) and some systems such as CAD (Computer-Aided Design), CAE (Computer-Aided Engineering), CAM (Computer-Aided Manufacturing), PDM (Product Data Management) and visualization system are adopted for these purposes. Specially, DMU system utilizes a visualization system that shows the 3D shape of a product on the computer and it gives a quick intuition to a person whether he/she is an engineer or not. It also can induce the effects of CE and QFD. SO, 0 company is developing a DMU system integrating CAD, visualization and PDM system. The main feature of the developed DMU system is that it is entirely integrated with PDM system, which means that the 3D shape of any part or assembly can be retrieved through PDM system. The DMU system will change the development process, which will increase the competitiveness of a developed product.