• 대한치과기공학회지
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• 제43권2호
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• pp.70-70
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• 2021

• 대한치과기공학회지
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• 제43권1호
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• pp.13-18
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• 2021

Purpose: This study aimed to compare the flexural properties and perform the Weibull analysis of photo-curing three-dimensional (3D) printing resin. Methods: Photo-curing temporary resin (3D polymer) was used as a printing resin. Specimens (65 × 10 × 3.3 ㎣) were prepared following the ISO 20975-1 guidelines and according to the different printing orientations using a digital light processing 3D printer (D2 120; Dentium). The flexural strength (FS), flexural modulus, and work of fracture (WOF) were measured using a universal testing machine (Instron 3344; Instron) at a crosshead speed of 5 mm/min. Results: In this study, the 0° orientation exhibited higher FS and WOF than the 45° orientation. Significant differences were found among the printing orientations (p<0.05). Specimens printed at the 0° orientation were the most accurate. In the Weibull analysis, 0° showed the greatest Weibull modulus (m), which represents a higher reliability. Conclusion: 3D printing should be selected and used by considering flexural properties, size accuracy, and reliability.

• 대한치과기공학회지
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• 제41권3호
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• pp.167-175
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• 2019

Purpose: This study was investigated the effect of multi-layer zirconia block type and design location on the mechanical properties of zirconia copings. Methods: Three kinds of multi-layered zirconia blocks (Snow princess multi layered block, Multi cherry, Dental zirconia pre-shaded blank) were used to identify the effects of the kinds of multi-layered zirconia blocks, design locations on mechanical characteristics of zirconia copings. 150 Zirconia copings were fabricated and fracture strength, hardness and microstructure were compared and evaluated. Results: Dental zirconia pre-shaded blank(2,256.9N) had the highest fracture strength of zirconia copings on all the design locations, and it was followed by Snow princess multi layered block(2,107.5N) and Multi cherry(917.0N). Snow princess multi layered block(1,949.7Hv) had the highest hardness of zirconia copings on all the design locations, and it was followed by Dental zirconia pre-shaded blank(1,671.7Hv) and Multi cherry(1,383.7Hv). The cervical layer had the highest fracture strength and hardness of zirconia copings in all the blocks, and it was followed by the cervical+gradation layer, the enamel layer, the enamel+gradation layer, and the gradation layer. Conclusion: It was found that the fracture strength and hardness were different according to the kinds of multilayer zirconia block and design location, and it was confirmed that it is lower than the fracture strength of white zirconia.

• 대한치과기공학회지
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• 제46권2호
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• pp.42-48
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• 2024

Purpose: The purpose of this study is to investigate the applications and prospects of big data in digital dental healthcare. Methods: The study included 30 participants in the dental field (dentists, technicians, professors, and graduate students). From June 25 to 30, 2023, the contents of the study were thoroughly explained, consent was obtained from the research subjects, and a questionnaire was administered via an internet service. The questionnaires of 28 participants who responded completely were used for analysis. The collected data were statistically processed using IBM SPSS Statistics ver. 22.0 (IBM). Results: The use of big data in digital dental healthcare, digital dental health system, mobile dental health, dental health analysis, and telehealthcare were all heavily surveyed, with an average score of 3.97 or higher on a 5-point Likert scale. The areas where big data can be utilized in digital dental healthcare are as follows. The utilization rate for three-dimensional digital product development via linkage with big data systems and industrial field manufacturing technology was found to be 4.11±0.67, and the analysis of trends by age in the occurrence of various oral diseases was found to be 4.00±0.98. Conclusion: In the future, research into the viability of big data's success in the medical data field, which is directly related to human life, is needed. Additionally, social policies and regulations regarding big data-related information and standards in dental healthcare are necessary.

• 대한치과기공학회지
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• 제43권3호
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• pp.93-98
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• 2021

Purpose: The aim of this study was to observe the surface roughness and surface topography of cobalt-chrome (Co-Cr) alloys with grinding time in dental barrel finishing. Methods: This study involved two types of Co-Cr alloys. Specimens were manufactured with the dimensions 10×10×2 mm. Each specimen was cast according to the manufacturer's instructions. The cast alloys were polished for 35 minutes at intervals of five minutes in an automatic barrel finishing. Specimens were imaged with a three-dimensional optical microscope to measure surface roughness. Results: BC specimens and GM specimens had the highest roughness (Ra) values in the ungrained control group, and the lowest Ra values were measured 20 minutes after grinding. Conclusion: The best conditions for grinding Co-Cr alloy using a dental barrel finishing were a weight ratio of polishing media, water, and compound of 150 g:200 g:5 g, and a rotation speed of 450 rpm. Grinding time to obtain appropriate surface roughness should be limited to 15 to 30 minutes.

• 대한치과기공학회지
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• 제40권4호
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• pp.249-259
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• 2018

Purpose: This study aimed to investigate the relationship between dental technology students' life stress and smartphone addiction in order to detect smartphone over-users early, prevent them from getting addicted, and obtain basic data for creating a positive environment for academic achievement by using smartphone in a right way. Methods: The subjects of this study were university students at D University and G University in Daejeon Metropolitan City and Gangwon-do. A questionnaire survey was conducted to the subjects who understood the purpose of this study and participated in it from March 1 to June 10, 2018, and 243 were finally analyzed except 24 questionnaires without sufficient answers. Results: As a result of multiple regression analysis with variables, which were significant in univariate analysis, as independent variables, there were gender and smartphone dependency as general characteristics affecting the degree of smartphone addiction, and family relations and future problems among stress sub-factors were selected as significant variables. Conclusion : In the case of college students, they choose the smartphone as the easiest way to relieve stress because they lack the time and space to actually release stress. Therefore, club activities or on-campus and extra-curricular activities are recommended, and it needs to seek a way to get rid of stress by solving the cause of stress through counseling.

• 대한치과기공학회지
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• 제41권2호
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• pp.123-135
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• 2019

Purpose: This study aims to prevent Smartphone addiction and provide a basic material for intervention strategy by inquiring into the correlation between interpersonal relations competency and Smartphone addiction. Methods: This study carried out a questionnaire survey oriented to 323 people who agreed to participate in this research. For the final analysis, this study selected 298 sheets of questionnaires excluding 25 sheets with insufficient response qualities. Results: According to the results of regression analysis, significant correlation between interpersonal relations competency and Smartphone addiction level was not observed. However, according to the results of correlation analysis, the subordinate factor of Smartphone addiction "directionality of virtual world" showed a significant negative correlation with "opinion expression regarding rights or refusal" of interpersonal relations competency (p<0.05), while "withdrawal," the subordinate factor of interpersonal relations competency and Smartphone addiction displayed a negative correlation with Smartphone addiction (p<0.05). Conclusion : However, the mean of the 3DP group was within the clinical tolerance suggested by the previous researchers. Based on this, dental prosthesis fabricated by 3D printing technology is considered to be clinically acceptable.

• 대한치과기공학회지
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• 제45권2호
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• pp.48-53
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• 2023

Purpose: This study aimed to provide the basic data for dental barrel finishing by observing the abrasiveness of the metal body according to the time of the barrel finishing. Methods: This study included three types of Co-Cr alloys. The specimens were manufactured by casting method using 10-mm diameter wax spheres (n=10). The cast alloys were polished for 60 minutes at intervals of 5 minutes in barrel finishing. The weight and volume of the specimens were measured, and the rate of change was calculated. The data obtained from the three groups (α=0.05) were compared and analyzed using one-way ANOVA. Results: As a result, the overall volume and weight of the group decreased after grinding compared with the control group. Conclusion: When grinding dental barrel finishing, no difference was observed in the processing rate depending on the type of alloy and the processing rate of the alloy body is within 30 minutes; hence, dental barrel finishing can be effectively used for grinding.

• 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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• 한국정보과학회언어공학연구회 2018년도 제30회 한글 및 한국어 정보처리 학술대회
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• pp.228-233
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• 2018

세벌식 한글 글쇠배열은 두벌식보다 글쇠 수가 많이 필요하다는 단점이 있으나, 자음의 종류를 구분할 필요가 없고 고속 타자에 구조적으로 더 유리하다는 장점도 있다. 통상적인 '이어치기'를 넘어 일명 '모아치기'와 '동시치기'처럼 컴퓨터 속기에서 쓰이는 원리를 반영한 입력 로직을 구현할 수 있는데, 이를 위해서는 전용 오토마타를 설계해야 하며 글쇠가 순서대로 눌러진 것뿐만 아니라 각 글쇠들이 눌러진 간격, 눌러졌다가 떼어진 시점, 둘 이상의 글쇠가 동시에 눌러지는 상황에 대해서 고려할 필요가 있다. 본 연구에서는 글쇠가 눌린 간격의 변화를 주로 이용하여 세벌식 기반의 입력 방식에 적용 가능한 동시치기 로직을 제안하였다. 그리고 이것이 오타를 자동 보정함으로써 타자의 편의를 실제로 개선할 수 있음을 공병우 세벌식 글쇠배열을 기준으로 한 실험을 통해 제시하였다.

• 한국산업융합학회 논문집
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• 제25권5호
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• pp.869-880
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• 2022

This study was conducted on 54 freshmen of the department of dental technology in D University to examine the effect of dental morphological practice mobile application utilization on the students' perception of class and satisfaction with learning. Major results of the study showed that satisfaction and utility towards functions of mobile application strengthened positive perception of dental morphology class, leading to improvement of satisfaction with learning, which suggested that functional convenience and utility in the use of applications were the effective factors for increasing the satisfaction with learning. Those results need to be given important consideration in designing the class using the mobile applications.