• Imaging Science in Dentistry
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• v.32 no.2
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• pp.107-111
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• 2002

Purpose : To compare the accuracy of digital subtraction images acquired by two different methods different in positioning four reference points for geometrical standardization. Materials and Methods : A total of 36 digital radiographic images of 6 volunteers were taken at the areas of the incisor, premolar, and molar of both the maxilla and mandible using the Digora system. Each image was moved 4 mm vertically and horizontally. Four oral and maxillofacial radiologists performed digital subtraction radiography between the paired images before and after movement using Emago (Oral Diagnostic Systems, Amsterdam, The Netherlands) and Sunny (Biomedisys Co., Seoul, Korea). The standard deviation of the internal gray value in Region of Interest (ROI) was statistically analyzed between the two programs using the paired t-test. Results : The standard deviation of pixel gray values from the digital subtraction images using the Sunny program were lower than that of the Emago program (p<0.05). All observers showed significant differences between each other when the Sunny program was used (p<0.05), but one observer showed a significantly higher score than other observers when they used Emago (p<0.05). The standard deviations of premolar area from both Sunny and Emago programs were significantly higher than those of anterior and molar regions (p<0.05). Conclusion: The subtracted images using the Sunny program were more accurate and sensitive than those taken using the Emago program.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.01a
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• pp.237-239
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• 2013

의료 기술이나 관련 장비가 발달해온 것과 달리, 현재의 단체 건강검진 환경에는 여러 가지 비효율적 요소들이 존재한다. 이에 따라 본 논문에서는 단체 건강검진 현장의 개선을 위한 전자태그(RFID) 기반 운영관리 시스템을 제안하고자 한다. 본 시스템은 데이터베이스를 이용하여 검진과정에서 수집되는 데이터들을 실시간으로 관리하고, 이를 토대로 현장 검진의들의 작업을 지원할 수 있는 정보를 제공한다. 아울러, 수검자들은 검진현장을 순회할 때 기존처럼 문서로 된 검진서식을 지참하는 것이 아니라 개인 RFID 카드를 이용하게 되고, 수검자들의 검진 내역 역시 지속적으로 추적이 가능하다. 결과적으로 제안하는 시스템을 통하여 전체 검진현장의 실시간 통합 관리가 가능하며, 단체 건강검진 현장의 업무효율성과 수검자 편의성이 증진될 수 있다. 아울러, 제안하는 시스템은 건강검진 현장에서 여러 가지 성과지표를 수집, 산출하여 검진 서비스의 지속적인 개선을 위한 토대를 제공한다.

• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.271-276
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• 2022

A company or organization introduces various management techniques and systems to achieve performance in a situation where it does not provide or fails to provide motivating factors such as the provision of parts required or required by employees to achieve desired results. It puts a burden on the employees mentally and physically. If this situation continues for a long time, it can be called job burnout. Job burnout is due to long-term exposure to increase in production based on new management techniques and new technologies implemented by companies or organizations for survival and to achieve excessive work demands through overtime and holiday work to achieve this. It is defined as a state of emotional and mental exhaustion. Therefore, this study investigated how mental and work-related bullying affects job burnout and job commitment, and how they affect turnover intention. As a result, workplace bullying has a positive effect on job burnout and has a direct effect on turnover intention. Therefore, in the case of dental clinics, it is judged that a lot of effort should be put into workplace bullying and job burnout in order to prevent the turnover of excellent talents.

• Journal of dental hygiene science
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• v.16 no.1
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• pp.93-100
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• 2016

The purpose of this study was to compare the changes of retentive force in different stud attachment systems for implant retained overdenture. Two commercially available attachments with different retentive forces were investigated: Kerator (pink, blue, red) and O-ring (orange, red). Two implant fixtures were vertically embedded in base mountings. Five pairs of each attachment were evaluated. A universal testing machine was used to evaluate the retentive force of two attachments during wear simulation. Surface characteristics of each attachment system were evaluated with scanning electron microscopy. Five pairs of each attachment were evaluated. Kerator pink showed the highest initial retention. After 2,500 cycles of wear-simulation, Kerator pink noted the largest decrease in retention. According to results of surface analysis, Worn surfaces were obtained in matrices and patrices. Heavy wears were observed in matrices. After 2 year-wear simulation, most attachments exhibited retention loss. Attachments using different kind of material exhibited dissimilar surface alterations.

• The Journal of Advanced Prosthodontics
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• v.3 no.2
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• pp.57-62
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• 2011

MATERIALS AND METHODS. Ceramics have a long history in fixed prosthodontics for achieving optimal esthetics and various materials have been used to improve ceramic core strength. However, there is a lack of information on how color is affected by fabrication procedure. The purpose of this study was to evaluate the effects of various dentin ceramic thicknesses and repeated firings on the color of zirconium oxide all-ceramic system (LavaTM) fabricated using CAD/CAM technology. MATERIALS AND METHODS. Thirty disc-shaped cores, 12 mm in diameter with a 1 mm thickness were fabricated from zirconium oxide based all ceramic systems ($Lava^{TM}$, 3M ESPE, St Paul, MN, USA) and divided into three groups (n = 10) according to veneering with dentin ceramic thicknesses: as 0.5, 1, or 1.5 mm. Repeated firings (3, 5, 7, or 9) were performed, and the color of the specimens was compared with the color after the initial firing. Color differences among ceramic specimens were measured using a spectrophotometer (VITA Easyshade, VITA Zahnfabrik, Bad $S{\ddot{a}}ckingen$, Germany) and data were expressed in CIELAB system coordinates. A repeated measures ANOVA and Bonferroni post hoc test were used to analyze the data (n = 10, ${\alpha}=.05$). RESULTS. $L^{\ast}a^{\ast}b^{\ast}$ values of the ceramic systems were affected by the number of firings (3, 5, 7, or 9 firings) (P<.001) and ceramic thickness (0.5, 1, or 1.5 mm) (P<.001). Significant interactions were present in $L^{\ast}a^{\ast}b^{\ast}$ values between the number of firings and ceramic thickness (P<.001). An increase in number of firings resulted in significant increase in $L^{\ast}$ values for both 0.5 mm and 1.5 mm thicknesses (P<.01, P=.013); however it decreased for 1 mm thickness (P<.01). The $a^{\ast}$ values increased for 1 mm and 1.5 mm thicknesses (P<.01), while it decreased for 0.5 mm specimens. The $b^{\ast}$ values increased significantly for all thicknesses (P<.01, P=.022). As the dentin ceramic thickness increased, significant reductions in $L^{\ast}$ values (P<.01) were recorded. There were significant increases in both $a^{\ast}$ and $b^{\ast}$ values (P<.01) as the dentin ceramic thickness increased. CONCLUSION. The number of firings and dentin ceramic thickness have a definite effect on the final color of all ceramic system tested. The mean ${\Delta}E$ value increased as the dentin ceramic thicknesses increased for zirconium-oxide based all ceramic specimens tested. However, the mean ${\Delta}E$ values were less than 3.7${\Delta}E$ units which is rated as a match in the oral environment.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.1
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• pp.1-13
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• 2012

Short implants are used in parts which have anatomical structures like maxillary sinus, inferior alveolar nerve and limited alveolar height due to severe alveolar bone resorption. In these case, there are no need of additional bone augmentation so there are advantages like reduced entire treatment time, reduced patient's discomfort and protection of important anatomical structures. The aim of this study is, in implants whose length is less than 10mm, to analyze the impact of implant length, diameter, location of implant placement, presence of bone graft, presence of prosthesis splinting on survival rates and marginal bone resorption. The samples used in this study were 227 implants, less than 10mm, placed in 137 patients in Wonkwang university dental hospital implant center. From dental charts the information about implant length, diameter, location of implant placement, presence of bone graft, presence of prosthesis splinting were obtained. Emago advanced v5.6(Oral diagnostic systems, Amsterdam, The Netherlands)program was used to measure the amount of marginal bone resorption. Out of total 227 implants, resulting in 96.5 % of survival rate. There was a tendency toward higher failure rates for the maxilla and bone graft site. No significant difference in marginal bone resorption was found associated with length of implants(p>0.05) and neither with the diameter of implants. Among the risk factors examined, more failure rates of short implants can be attributed to poor bone quality in the maxilla and presence of bone graft. At implants under 10mm, length, diameter, location of implant placement, bone graft and splinting of prosthesis didn't affect marginal bone loss.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.2
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• pp.222-233
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• 2007

One of the most important and basic test of dental restorative materials is the evaluation of microleakage into the tooth-restorative interface. There are many techniques to test microleakage, but most of them have several disadvantages. Recently developed microtomography(micro-CT) can provide the three dimensional image and information about the internal component in non-destructive way, therefore using micro-CT, it is possible to evaluate microleakage exactly in quantitative manner. The purpose of this study is to find a new method for quantitative and non-destructive evaluation of microleakage in composite resin restorations using micro-CT and to compare the new method with conventional dye penetration method. Thus, microleakages of two kinds of dentin bonding systems were evaluated with above two methods. 40 extracted sound human premolars were randomly divided into two groups consisting of 20 samples and restored accordingly. Group 1 : Class V resin restorations with $Adper^{TM}$ Singe Bond Group, 2 : Class V resin restorations with $Adper^{TM}\;Promp^{TM}$ L-pop. The $Filtek^{TM}$ Supreme was applied to the Class V cavities of all teeth. After that, 10 teeth from each group were applied to evaluation of microleakage using micro-CT, and other 10 teeth from each group were using conventional dye penetration method. The conclusions of this study were as follow : 1 Using micro-CT, Group 1 showed significantly less microleakage than Group 2 and there was statistically significant difference(p<0.01) between two groups. 2. Using conventional dye penetration method, Group 1 leaked less than Group 2 and there was statistically significant difference(p<0.01) between two groups 3. The difference between two groups is more evident in the method using micro-CT. 4. In all two methods, microleakage appeared more into the cavities to dentinal margins than enamel margins.

• Journal of the Korea Society of Computer and Information
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• v.24 no.11
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• pp.229-234
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• 2019

This study is an empirical study to examine how the family-friendly corporate culture affects organizational commitment and job performance for ICT companies in Korea. Therefore, the purpose of the study is to investigate the effects of family-friendly culture of ICT companies on the organizational commitment and job performance of their employees. To this end, the impacts of internal factors of family-friendly corporate culture on their organizational commitment and job performance of the employees of ICT companies in South Korean are empirically analyzed. And the findings of the empirical investigation are as follows: Family-friendly Organizational culture and Family-Friendly Welfare System have positive effects on the organizational commitment, and Organizational commitment, in return, has positive effects on the job performance. But the Family-friendly working environment is found to have NO significant effects on the Organizational commitment. These results confirm the characteristics of workers who prefer family-friendly welfare systems with economic rewards rather than formal family-friendly programs.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.3_4
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• pp.239-246
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• 2004

Image snapping for an image moves the cursor location to nearby features in the image, such as edges. In this paper, we propose geometric snapping for 3D triangular meshes, which is extended from image snapping. Similar to image snapping, geometric snapping also moves the cursor location naturally to a location which represents main geometric features in the 3D triangular meshes. Movement of cursor is based on the approximate curvatures which appear geometric features on the 3D triangular meshes. The proposed geometric snapping can be applied to extract main geometric features on 3D triangular meshes. Moreover, it can be applied to extract the geometric features of a tooth which are necessary for generating the occlusal surfaces in dental prostheses.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.2
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• pp.164-172
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• 2021

Purpose: The purpose of this study was to analyze the level of interest that common Internet users have in dental implant using a Google Trends, and to compare the level of interest with big data from National Health Insurance Service. Materials and methods: Google Trends provides a relative search volume for search keywords, which is the average data that visualizes the frequency of searches for those keywords over a specific period of time. Implant was selected as the search keyword to evaluate changes in time flows of general Internet users' interest from 2015 to 2019 with trend line and 6 month moving average. Relative search volume for implant was analyzed with the number of patients who received National Health Insurance coverage for implant. Interest in implant and conventional denture was compared and popular related search keywords were analyzed. Results: Relative search volume for implant has increased gradually and showed a significant positive correlation with the total number of patients (P<.01). Interest in implant was higher than denture for most of the time. Keywords related to implant cost were most frequently observed in all years and related search on implant procedure was increasing. Conclusion: Within the limitations of this study, the public interest in dental implant was gradually increasing and specific areas of interest were changing. Web-based Google Trends data was also compared with traditional data and significant correlation was confirmed.