• Journal of Welding and Joining
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• 제32권4호
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• pp.10-14
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• 2014

Laser aided Direct Metal Tooling(DMT) process is a kind of Additive Manufacturing processes (or 3D-Printing processes), which is developed for using various commercial steel powders such as P20, P21, SUS420, H13, D2 and other non-ferrous metal powders, aluminum alloys, titanium alloys, copper alloys and so on. The DMT process is a versatile process which can be applied to various fields like the mold industry, the medical industry, and the defense industry. Among of them, the application of DMT process to the mold industry is one of the most attractive and practical applications since the conformal cooling channel core of injection molds can be fabricated at the slightly expensive cost by using the hybrid fabrication method of DMT technology compared to the part fabricated with the machining technology. The main objectives of this study are to provide various characteristics of the parts made by DMT process compared to the same parts machined from bulk materials and prove the performance of the injection mold equipped with the conformal cooling channel core which is fabricated by the hybrid method of DMT process.

• 대한치과교정학회지
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• 제50권5호
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• pp.346-355
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• 2020

The treatment of skeletal Class III malocclusion in adolescents is challenging. Maxillary protraction, particularly that using bone anchorage, has been proven to be an effective method for the stimulation of maxillary growth. However, the conventional procedure, which involves the surgical implantation of mini-plates, is traumatic and associated with a high risk. Three-dimensional (3D) digital technology offers the possibility of individualized treatment. Customized mini-plates can be designed according to the shape of the maxillary surface and the positions of the roots on cone-beam computed tomography scans; this reduces both the surgical risk and patient trauma. Here we report a case involving a 12-year-old adolescent girl with skeletal Class III malocclusion and midface deficiency that was treated in two phases. In phase 1, rapid maxillary expansion and protraction were performed using 3D-printed mini-plates for anchorage. The mini-plates exhibited better adaptation to the bone contour, and titanium screw implantation was safer because of the customized design. The orthopedic force applied to each mini-plate was approximately 400-500 g, and the plates remained stable during the maxillary protraction process, which exhibited efficacious orthopedic effects and significantly improved the facial profile and esthetics. In phase 2, fixed appliances were used for alignment and leveling of the maxillary and mandibular dentitions. The complete two-phase treatment lasted for 24 months. After 48 months of retention, the treatment outcomes remained stable.

• 융복합기술연구소 논문집
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• 제6권2호
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• pp.41-46
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• 2016

Based on Regional Industry Development Plan in 2014, machinery part industry and medical instrument industry has been designated as core industries of Chung-buk area. Machinery part industry plays an important role in economic growth of chung-buk area and it has been faced with signigicant changes - such as SMART factory and IoT(Internet of things). Also, medical instrument industry with 3D printing technology grows rapidly in Chung-buk area. It is believed that medical instrument could be next cash-cow items for Chung-buk area. In this paper, we survey, analyze and summarize the current machinery part industry and medical instrument industry focused on Chunk-buk Area.

• 한국방사선학회논문지
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• 제14권7호
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• pp.899-906
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• 2020

WSS 측면 검사는 척추의 질환을 진단하기 위해 매우 중요한 검사이다. 최근 대면적의 Long Length Detector가 보급되고 있어 피폭선량과 검사 시간을 효율적으로 줄일 수 있으며, 낙상 고위험군 환자 및 소아, 청소년기 환자의 검사에 매우 효율적으로 적용할 수 있다. 하지만 1회 조사로 영상을 얻기 때문에 기하학적인 척추의 해부학적 구조상 허리뼈 보다 목뼈 부근이 상대적으로 체적이 적어 목뼈 부위의 영상 품질은 진단 가치가 매우 하락한다는 단점이 있다. 이에 본 연구는 WSS 측면 검사에서 균일한 영상품질을 얻기 위해 3D 프린팅 기술과 구리 필라멘트를 이용하여 부가 필터를 제작하고 결과를 분석하고자 한다. 3D 프린팅 기술은 원하는 모양을 손쉽게 출력할 수 있는 장점이 있어 산업 분야 전반에 광범위하게 사용되고 있으며, 최근 구리 소재의 필라멘트가 개발되어 부가 필터로서의 가능성을 확인하였다. WSS 측면 검사에서 부가 필터 적용시 CNR과 SNR이 우수하게 측정되어 부가필터의 사용 가능성을 확인 하였다.

• 한국방사선학회논문지
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• 제14권5호
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• pp.537-543
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• 2020

현대사회의 노인 인구는 첨단 의료기술과 최소 침습 수술로 인해 빠르게 성장하고 있다. 따라서 의료기기를 사용하는 경향이 증가하기 때문에 병원성 감염이 우려된다. 따라서 현대 의학의 최우선 목표는 감염예방이다. 최근 3D 프린팅을 이용하여 환자 맞춤형 임플란트 이식술이 늘고 있다. 대표적 재료로 이용되는 것이 수산화인회석이다. 현재 HA 디스크 멸균을 위한 흡수선량 기준이 없으므로, HA 디스크 표면에 오염된 대장균과 충치균을 감마선 코발트와 선형 가속기를 이용하여 각 흡수선량 0, 0.5, 1.0, 3.0, 5.0 kGy로 조사 후, 십진 희석법으로 검체에서 균 수를 측정하였다. 멸균 후 대장균, 충치균의 생존 비교분석을 위해 비모수 검정법을 시행하였으며, 그 결과 대장균은 1 kGy 이상, 충치균은 3 kGy 이상에서 멸균되었다. 방사선 멸균 흡수선량 권고사항보다 낮은 수치에서 멸균을 시행하는 것도 가능할 것으로 생각된다.

• 대한방사선기술학회지:방사선기술과학
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• 제45권3호
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• pp.205-211
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• 2022

This study aimed to provide basic data for 3D printing in the medical health field by developing upper wear fixation device (UWFD), an auxiliary device for shortening chest AP examination time on emergency room beds and non-contact with patients. The standard of hooks was modeled according to the bed frame using the Autodesk Fusion 360. It was printed with Form2 (Formlabs, Somerville, MA, USA), as SLA (stereo lithography apparatus) method, and was washed and hardened using Form Wash and Form Cure. The completed UWFD conducted an online survey on 4 items of stability, convenience, availability, preference and general characteristics. The total stability average was 3.93±0.80, the total convenience average was 3.93±0.68, the total availability average was 4.01±0.89, and the total preference average was 3.80±1.08. This study was significant in suggesting improvements in the general X-ray examination process in the emergency room by designing and making aids to easily fixing the patient's top to the frame of the emergency bed while meeting promptness and non-contact with the patient.

• Tissue Engineering and Regenerative Medicine
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• 제15권6호
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• pp.761-769
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• 2018

BACKGROUND: Bioprinting has recently appeared as a powerful tool for building complex tissue and organ structures. However, the application of bioprinting to regenerative medicine has limitations, due to the restricted choices of bio-ink for cytocompatible cell encapsulation and the integrity of the fabricated structures. METHODS: In this study, we developed hybrid bio-inks based on acrylated hyaluronic acid (HA) for immobilizing bio-active peptides and tyramine-conjugated hyaluronic acids for fast gelation. RESULTS: Conventional acrylated HA-based hydrogels have a gelation time of more than 30 min, whereas hybrid bio-ink has been rapidly gelated within 200 s. Fibroblast cells cultured in this hybrid bio-ink up to 7 days showed >90% viability. As a guidance cue for stem cell differentiation, we immobilized four different bio-active peptides: BMP-7-derived peptides (BMP-7D) and osteopontin for osteogenesis, and substance-P (SP) and Ac-SDKP (SDKP) for angiogenesis. Mesenchymal stem cells cultured in these hybrid bio-inks showed the highest angiogenic and osteogenic activity cultured in bio-ink immobilized with a SP or BMP-7D peptide. This bio-ink was loaded in a three-dimensional (3D) bioprinting device showing reproducible printing features. CONCLUSION: We have developed bio-inks that combine biochemical and mechanical cues. Biochemical cues were able to regulate differentiation of cells, and mechanical cues enabled printing structuring. This multi-functional bio-ink can be used for complex tissue engineering and regenerative medicine.

• 한국방사선학회논문지
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• 제17권7호
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• pp.1099-1108
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• 2023

Mortise view 검사는 발목관절 검사로써 발목관절의 외상이나 염좌, 탈구가 의심되는 병변의 유무를 관찰한다. mortise view 검사 시 사용되는 보조기구는 영상에 인공물을 발생하거나, 종류가 다양하지 않아 환자 맞춤형으로 제작되지 않고 가격이 비싸다. 이에 본 연구는 3D 프린팅 기술을 이용하여 mortise view 검사보조기구(ShinHan Device; SHD)를 제작하였다. SHD를 사용했을 때와 시제품인 hologic tool을 사용했을 때의 목말종아리관절, mortise 관절, 목말정강관절의 길이를 5명의 연구자가 측정하여 평가하였다. SHD를 사용했을 때 평균값의 범위는 TTJ에서 39.42~39.47 mm, TCJ 31.41~31.57 mm, MJ 21.21~21.23 mm의 범위로 나타났다. hologic tool를 사용했을 때는 TTJ 39.73~39.79 mm, TCJ 31.46~31.50 mm, MJ 21.31~21.35 mm의 범위로 측정되었다. 본 연구결과, 모든 위치에서의 오차범위가 hologic tool에 비해 SHD를 사용 때 TTJ는 24%, TCJ는 17%, MJ는 36% 감소하였으며, SHD를 사용하였을 때 재현성 높은 검사자세를 구현할 수 있었으며(ICC=0.99), hologic tool에서 발생하던 인공물을 제거한 영상을 획득할 수 있었다.

• 한국융합학회논문지
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• 제12권8호
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• pp.187-195
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• 2021

최근 치과에서 사용되는 10종의 폴리머 기구에 대한 세포독성을 평가하기 위하여 L-929 세포를 이용한 MTT 시험을 시행하였다. 검체를 4g 당 20mL의 비율로 제조한 37℃의 RPMI 1640 용액에서 24시간 동안 용출한 후 식품의약품안전처 고시 제2020-12호 의료기기 생물학적 안전에 관한 공통기준규격에 따라 검체 용출액과 공시험액, 음성 및 양성대조를 사용하여, 37℃, 5% CO₂ Incubator에서 24시간 배양하여 ELISA reader로 판정한 결과, Intraoral camera는 용출물 농도 약 50%에서 약 70% 이상의 세포 생존율을 나타냈나 Plastic impression tray, 3D printing tweezer, Impression disposable syringe, Dental floss holder, Hand implant scaler, Surgical retractor, Oral scanner tip, Dental mirror, Water pick tip은 모두 용출물 농도 100%에서 70% 이상의 세포 생존율로 세포독성을 나타내지 않아 구강점막에 직접 접촉하여 사용이 가능한 기구로 평가되었다.

• 통합자연과학논문집
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• 제17권2호
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• pp.53-58
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• 2024

This study explores the enhancement of mechanical properties in Polymethyl Methacrylate (PMMA) composites through the incorporation of Methyl Methacrylate (MMA) and Ethylene Glycol Dimethacrylate (EGDMA). Utilizing Digital Light Processing (DLP) technology, we conducted a series of experiments to analyze the impact of varying concentrations of MMA and EGDMA on PMMA. The results indicate that while MMA demonstrates non-linear and variable mechanical strength across different PMMA concentrations, EGDMA consistently improves mechanical strength as PMMA concentration increases. This consistent enhancement by EGDMA suggests a stable and predictable reinforcement effect, which is critical for applications requiring high mechanical strength. Our comparative analysis highlights that EGDMA is a more effective additive than MMA for optimizing the mechanical performance of PMMA composites. Specifically, EGDMA's ability to provide uniform reinforcement across various PMMA concentrations makes it ideal for high-strength applications. These findings are significant for material scientists and engineers focused on the design and development of advanced PMMA-based materials. In conclusion, this research underscores the importance of selecting appropriate additives to enhance the mechanical properties of PMMA composites. The superior performance of EGDMA in reinforcing PMMA suggests its potential for broader applications in fields such as automotive, construction, medical devices, and 3D printing. This study provides valuable insights that can guide future research and development in high-performance composite materials, paving the way for innovative applications and improved material efficiency.