• 반도체디스플레이기술학회지
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• 제20권3호
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• pp.172-177
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• 2021

The HUD (Head-up Display) device for vehicles has gradually been advanced in connection with ADAS (Advanced Driver Assistant System) for the safety and the convenience of driving. In this paper, the major features (e.g. speed, RPM, etc.) of vehicles is received through the ECU and the route information is received through the navigating API, configurating the integrated GUI. And, the optical system is configured based on DLP (Digital Light Processing) to evaluate the visibility depending on the resolution change of the GUI. The IoT HUD system proposed in this paper has the scalability to flexibly add not only the ECU but also various cloud-based driving-related information.

• The Journal of Advanced Prosthodontics
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• 제12권4호
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• pp.225-232
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• 2020

PURPOSE. This study aimed to fabricate provisional crowns at varying build directions using the digital light processing (DLP)-based 3D printing and evaluate the marginal and internal fit of the provisional crowns using the silicone replica technique (SRT). MATERIALS AND METHODS. The prepared resin tooth was scanned and a single crown was designed using computer-aided design (CAD) software. Provisional crowns were printed using a DLP-based 3D printer at 6 directions (120°, 135°, 150°, 180°, 210°, 225°) with 10 crowns in each direction. In total, sixty crowns were printed. To measure the marginal and internal fit, a silicone replica was fabricated and the thickness of the silicone impression material was measured using a digital microscope. Sixteen reference points were set and divided into the following 4 groups: marginal gap (MG), cervical gap (CG), axial gap (AG), and occlusal gap (OG). The measurements were statistically analyzed using one-way ANOVA and Dunnett T3. RESULTS. MG, CG, and OG were significantly different by build angle groups (P<.05). The MG and CG were significantly larger in the 120° group than in other groups. OG was the smallest in the 150° and 180° and the largest in the 120° and 135° groups. CONCLUSION. The marginal and internal fit of the 3D-printed provisional crowns can vary depending on the build angle and the best fit was achieved with build angles of 150° and 180°.

• 대한심미치과학회지
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• 제27권2호
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• pp.82-96
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• 2018

3D 프린팅은 삼차원 이미지 정보를 이용하여 레이어로 분할한 후 선택한 소재를 적층하여 가공하는 방법을 말한다. 소재를 적층하는 방법에 따라 다양한 종류의 3D 프린팅이 존재하는데 최근 치과분야에서는 SLA방식과 DLP방식으로 광원을 이용한 경화를 통해 적층 가공하는 3D 프린팅이 널리 보급되어 사용되고 있다. 전악 범위의 3D프린팅 치과용 모델은 전통적인 인상 채득으로 제작된 스톤모델보다는 다소 정확성이 부족한 것으로 보고되었으나, 같은 STL파일을 이용하여 4분악 범위를 3D 프린팅한 모델은 밀링 방법으로 가공한 모델보다 정확하였다. 디자인 소프트웨어의 활용도에 따라 보철치료의 진단, 임시 보철물의 제작, 의치의 제작이 가능하였다. 교정에서는 투명 교정 모델과 브라켓 간접 부착을 위한 트레이 제작이 가능하였다. 임플란트 수술에 있어서 CT를 기반으로 한 정확한 위치에 임플란트를 식립하는 가이드 제작에 활용하고 있다. 출력 방식의 발전으로 인하여 3D 프린터의 출력시간이 계속적으로 단축되고 있으며, 이로 인해 치과 진료실 내에서 3D 프린터가 기존의 전통적인 가공 방법을 대체할 수 있을 것으로 기대한다.

• The Journal of Advanced Prosthodontics
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• 제15권2호
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• pp.72-79
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• 2023

PURPOSE. The purpose of this in vitro study was to compare the accuracy of various 3D printers and a milling machine. MATERIALS AND METHODS. The die model was designed using CAD (Autodesk Inventor 2018 sp3). The 30 ㎛ cement space was given to the die and the ideal crown of the mandibular left first molar was designed using CAD (ExoCAD). The crowns were produced using the milling machine (Imes-icore 250i) and the 3D printers (Zenith U, Zenith D, W11) and they were divided into four groups. In all groups, the interior of each crown was scanned (Identica blue) and superimposed (Geomagic Control X) with the previously designed die. The difference between the die and the actual crown was measured at specific points. The Kruskal-Wallis test, the Mann-Whitney test, and Bonferroni's method were performed with a statistical analysis software (P < .008 in inter-group comparison P < .001 in intra-group comparison). RESULTS. In all groups, the center of the occlusal area and the anti-rotational dimple area showed significantly greater difference and the marginal area showed the smallest difference comparatively. The mean value of the difference in each area and the sum of the differences were higher in order of W11, Imes-icore 250i, Zenith D, and Zenith U. CONCLUSION. The digital light processing (DLP) method shows higher accuracy compared to the sereolithography (SLA) method using the same resin material.

• 대한치과보철학회지
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• 제58권1호
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• pp.7-13
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• 2020

목적: 본 연구의 목적은 절삭 가공법 및 적층 가공법에 의해 제작된 3본 고정성 국소의치의 변연 및 내면 적합도를 비교하는 것이다. 재료 및 방법: 상악 좌측 제2소구치가 상실된 3본 고정성 국소의치 지대치를 제작하고(주모형), 구강 스캐너를 이용해 주모형 스캔 데이터를 얻었다. 3본 고정성 보철물은 다음과 같은 3가지 방법으로 제작하였다: Milled 3-unit fixed dental prostheses (FDP) (MIL군), digital light processing (DLP) 3D printed 3-unit FDP (D3P군), stereolithography apparatus (SLA) 3D printed 3-unit FDP (S3P군). 보철물의 변연 및 내면 적합도와 내면 정밀도 평가하기 위해 각각 triple-scan protocol과 콤비네이션 수식을 사용하여 스캔 데이터를 중첩하였다. 3차원 분석 프로그램(Geomagic control X)을 사용하여 root mean square (RMS) 값과 color difference map 통해 정량 및 정성 분석 시행하였다. Kruskal-Wallis test (α = .05)와 Mann-Whitney U test 및 Bonferroni correction (α = .05/3 = .017)을 이용하여 통계 분석하였다. 결과: S3P군의 변연 적합도는 MIL군과 D3P군에 비해 우수하였으며, MIL군과 D3P군은 비슷한 수준을 보였다. D3P군과 S3P군은 MIL군에 비해 상대적으로 우수한 내면 적합도를 보였으며, D3P군과 S3P군 사이에는 유의한 차이가 없었다. 한편, MIL군, S3P군, 그리고 D3P군 순으로 우수한 정밀도를 보였다. 결론: 본 연구의 한계 내에서 적층 가공법으로 제작된 3본 고정성 보철물은 절삭 가공법으로 제작된 3본 고정성 보철물에 비해 우수한 변연 및 내면 적합도를 보인 반면 정밀도는 떨어지는 것으로 나타났다.

• 대한치과보철학회지
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• 제57권3호
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• pp.225-231
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• 2019

목적: 본 연구의 목적은 적층 가공법, 절삭 가공법 및 직접법에 의해 제작된 임시 수복용 레진의 파절강도와 굴곡강도를 비교하는 것이다. 재료 및 방법: 각각 다른 방법들로 제작된 5가지 방법의 임시 수복용 레진을 조사하였다: Stereolithography apparatus (SLA) 3D 프린터를 이용한 적층 가공법(S3Z군), 두 가지 digital light processing (DLP) 3D 프린터를 이용한 적층 가공법(D3Z군, D3P군), 절삭 가공법(MIL군), 전통적인 방식의 직접법(CON군). 파절강도 시험은 각 방법을 이용하여 소구치 형태의 시편을 준비하였고, 굴곡강도 시험은 각 방법을 이용하여 직사각형의 바 형태의 시편 ($25{\times}2{\times}2mm$)을 준비하여 universal testing machine (UTM)을 사용하여 평가하였다. 결과: 적층 가공을 이용해 제작된 S3Z군, D3Z군, D3P군의 파절강도는 MIL군 및 CON군의 파절강도와 유의한 차이가 없었다 (P > .05/10 = .005). 한편, S3Z군, D3P군, MIL군의 굴곡강도는 CON군의 굴곡강도보다 높았으나 (P < .05), D3Z군의 굴곡강도는 CON군보다 낮았다 (P < .05). 결론: 본 연구의 한계 내에서 적층 가공법으로 제작된 임시 수복용 레진은 절삭 가공법과 기존에 사용되었던 직접법에 의해 제작된 임시수복용 레진과 임상적으로 유사한 파절강도, 굴곡강도를 나타냈다.

• The Journal of Advanced Prosthodontics
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• 제10권5호
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• pp.367-373
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• 2018

PURPOSE. To evaluate the fit of a crown produced based on a 3D printed model and to investigate its clinical applicability. MATERIALS AND METHODS. A master die was fabricated with epoxy. Stone dies were fabricated from conventional impressions (Conventional stone die group: CS, n=10). Digital virtual dies were fabricated by making digital impressions (Digital Virtual die group: VD, n=10). 3D data obtained from the digital impression was used to fabricate 3D printed models (DLP die group: DD, n=10, PolyJet die group: PD, n=10). A total of 40 crowns were fabricated with a milling machine, based on CS, VD, DD and PD. The inner surface of all crowns was superimposed with the master die files by the "Best-fit alignment" method using the analysis software. One-way and 2-way ANOVA were performed to identify significant differences among the groups and areas and their interactive effects (${\alpha}=.05$). Tukey's HSD was used for post-hoc analysis. RESULTS. One-way ANOVA results revealed a significantly higher RMS value in the 3D printed models (DD and PD) than in the CS and DV. The RMS values of PD were the largest among the four groups. Statistically significant differences among groups (P<.001) and between areas (P<.001) were further revealed by 2-way ANOVA. CONCLUSION. Although the fit of crowns fabricated based on the 3D printed models (DD and PD) was inferior to that of crowns prepared with CS and DV, the values of all four groups were within the clinically acceptable range (<$120{\mu}m$).

• The Journal of Advanced Prosthodontics
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• 제14권6호
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• pp.360-368
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• 2022

PURPOSE. This study assessed the physical and mechanical properties of interim crown materials fabricated using various digital techniques after accelerated aging. MATERIALS AND METHODS. Three groups of interim dental restorative materials (N = 20) were tested. The first group (CO) was fabricated using a conventional manual method. The second group (ML) was prepared from prefabricated resin blocks for the milling method and cut into specimen sizes using a cutting disc. The third group (3D) was additively manufactured using a digital light-processing (DLP) 3D printer. Aging acceleration treatments using toothbrushing and thermocycling simulators were applied to half of the specimens corresponding to three years of usage in the oral environment (N = 10). Surface roughness (Ra), Vickers microhardness, 3-point bending, sorption, and solubility tests were performed. A 2-way analysis of variance (ANOVA) and Fisher's multiple comparison test were used to compare the results among the groups. RESULTS. The mean surface roughness (Ra) of the resin after accelerated aging was significantly higher in the CO and ML groups than that before aging, but not in the 3D group. All groups showed reduced hardness after accelerated aging. The flexural strength values were highest in the 3D group, followed by the ML and CO groups after accelerated aging. Accelerated aging significantly reduced water sorption in the ML group. CONCLUSION. According to the tested material and 3D printer type, both 3D-printed and milled interim restoration resins showed higher flexural strength and modulus, and lower surface roughness than those prepared by the conventional method after accelerated aging.

• The Journal of Advanced Prosthodontics
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• 제14권3호
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• pp.150-161
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• 2022

PURPOSE. The purpose of the study was to assess the influence of build orientations and density of support structures on the trueness of the 3D printed removable partial denture (RPD) frameworks. MATERIALS AND METHODS. A maxillary Kennedy class III and mandibular class I casts were 3D scanned and used to design and produce two 3D virtual models of RPD frameworks. Using digital light processing (DLP) 3D printing, 47 RPD frameworks were fabricated at 3 different build orientations (100, 135 and 150-degree angles) and 2 support structure densities. All frameworks were scanned and 3D compared to the original virtual RPD models by metrology software to check 3D deviations quantitatively and qualitatively. The accuracy data were statistically analyzed using one-way ANOVA for build orientation comparison and independent sample t-test for structure density comparison at (α = .05). Points study analysis targeting RPD components and representative color maps were also studied. RESULTS. The build orientation of 135-degree angle of the maxillary frameworks showed the lowest deviation at the clasp arms of tooth 26 of the 135-degree angle group. The mandibular frameworks with 150-degree angle build orientation showed the least deviation at the rest on tooth 44 and the arm of the I-bar clasp of tooth 45. No significant difference was seen between different support structure densities. CONCLUSION. Build orientation had an influence on the accuracy of the frameworks, especially at a 135-degree angle of maxillary design and 150-degree of mandibular design. The difference in the support's density structure revealed no considerable effect on the accuracy.

• 센서학회지
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• 제30권6호
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• pp.388-394
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• 2021

The conventional microelectromechanical system (MEMS) process has been used to fabricate sensors with high costs and high-volume productions. Emerging 3D printing can utilize various materials and quickly fabricate a product using low-cost equipment rather than traditional manufacturing processes. 3D printing also can produce the sensor using various materials and design its sensing structure with freely optimized shapes. Hence, 3D printing is expected to be a new technology that can produce sensors on-site and respond to on-demand demand by combining it with open platform technology. Therefore, this paper reviews three standard 3D printing technologies, such as Fused Deposition Modeling (FDM), Direct Ink Writing (DIW), and Digital Light Processing (DLP), which can apply to the sensor fabrication process. The review focuses on strain/load sensors having both sensing material features and structural features as well. NCPC (Nano Carbon Piezoresistive Composite) is also introduced as a promising 3D material due to its favorable sensing characteristics.