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Purpose: The purpose of this study was to observe the microstructural changes of surface in the specimens, performing the shear bond strength testing. The currently most used non-precious alloys are nickel-chromium based alloys with or without beryllium. However, their biocompatibility has been questioned concerning possible damages to the health of the patient and professionals involved in the fabrication of prosthesis caused by long exposure to Ni and Be. An option to nickel-chromium alloys is the cobalt-chromium alloy, an alternative that does not sacrifice the physical properties of the metal porcelain systems. Studies in the animals substantially show that the cobalt-chromium alloys are relatively well tolerated, being therefore more biocompatible than the nickelchromium alloys. Methods: Non-addition Be to nickel-chromium based alloy(Bellabond plus) and cobalt-chromium alloy which has been widely used(Wirobond C) fused with ZEO light porcelain classified control group and cobalt-chromium alloy which is developing alloy of Alphadent company in Korea(Alphadent alloy) fused with ZEO light porcelain classified experimental group. The specimens of 4 4 0.5 were prepared as-cast and as-opaque to cast body to analyze the mechanical characteristic change, the microstructure of alloy surface. The phase change was used to observe through XRD analysis and OM/SEM was used to observe the surface of specimens as-cast and asopaque to cast body. Chemical formation of their elements was measured with EDS. Then hardness was measured with Micro Vicker’s hardness tester. Shear bond strength test thirty specimens of 10 10 2 was prepared, veneered, 3 high and 3 in diameter, over the alloy specimens. The shear bond strength test was performed in a universal testing machine(UTM) with a cross head speed of 0.5 /min. Ultimate shear bond strength data were analyzed with one-way ANOVA and the Scheffe’s test (P<0.05). Within the limits of this study, the following conclusions were drawn: The X-ray diffraction analysis results for the as-cast and as-opaque specimens showed that the major relative intensity of Bellabond plus alloy were changed smaller than Wirobond C and Alphadent Co-Cr based alloys. Results: Microstructural analysis results for the opaque specimens showed all the alloys increased carbides and precipitation(PPT). Alphadent Co-Cr based alloy showed the carbides of lamellar type. The Vickers hardness results for the opaque specimens showed Wirobond C and Alphadent Co-Cr based alloys were increaser than before ascast, but Bellabond plus alloy relatively decreased. The mean shear bond strengths ( ) were: 33.11 for Wirobond C/ZEO light; 25.00 for Alphadent Co-Cr alloy/ZEO light; 18.02 for Bellabond plus/ZEO light. Conclusion: The mean shear bond strengths for Co-Cr and Ni-Cr based alloy were significantly different. But the all groups showed metal-metal oxide modes in shear bond strengths test at the interface.

Purpose: The purpose of this study was to analyze dental laboratory’s working environment and turnover intention level and to examine its correlation. Methods: 180 dental technicians in Seoul, Incheon, and Chungnam area were selected. Survey was carried out from April 6, 2009 to May 20, 2009 by using self-administered questionnaire. As for the tools for this study, the structured questionnaire was used with its proven reliability and feasibility, and the contents of questionnaire consisted of 43 questions on the basis of related references. The questionnaire consisted of total 32 questions which included general attribute of subjects(14 questions), working Environment(20 questions) and turnover intention(9 questions). The data analysis was processed by computerized system with SPSS 12.0. Statistical analysis techniques included frequency, percentage, T-test, F-test analysis and regression analysis. Results: As a result of analyzing the research subjects’ working environment level, there was significant difference in the item of health(P<0.05). The average in the working environment was indicated to be high with 1.53. As a result of analyzing the research subjects’ turnover intention level, there was difference in the item of working hours a day(Hour), job satisfaction level, plan for task continuity, most difficulty given task(P<0.05). The average of turnover intention was indicated to be high with 2.85. Conclusion: Correlation between working environment and turnover intention, most of variables were indicated to have reverse correlation, thereby having been shown that the worse working environment leads to the more turnover intention.

Purpose: It is necessary for dental technicians exposed to hazardous chemicals in the dental laboratories to be informedof the various harmful effects of chemicals for their health and safety. The purposes of this study was to investigate theactual condition of the use of MSDS in dental laboratories and the recognition rate of MSDS for dental technicians. Methods: 231 dental technicians who were self-written questionnaire. The results were analyzed by SPSS 12.0. The answers to the questionnaire underwent frequency analysis, chi-square test and correlation analysis were performed to investigate association between health effects and recognition rate of chemical information. Results: The results from the effects of damage caused by chemicals 60.7%, and when it was less than 2 years working experience 47.6%. Currently any dental laboratories(rooms) was not furnished MSDS(0%) and even similar data furnishing rate was only 17.3%. Answer rate of ‘Do not know about MSDS’ was 73.6%. In addition to, education in the types and characteristics of chemicals(74.5%) does not receive all the higher education. For the question of ‘To prevent human risks and accidents, is to provide chemical information needed’, the answer rate of ‘needed’ was 87.2%. Moreover, the answer rate of ‘To provide chemical information that could prevent accidents’ was 76.6%. Therefore it was found that dental technicians need to be provided for chemical information. In addition, they wanted to get education related to chemicals used in the workplace(80.5%), and 90.9% was answered that they was willing to keep MSDS in they workplace. Conclusion: This study investigated the current dental laboratories(rooms) and the MSDS for the awareness and recognition of workers was very low, education was not being conducted properly. The dental laboratories(rooms) of the compact characteristics of the MSDS was not reasonably accessible and the furnishing location, dental laboratories(rooms) for the real item was needed for improvement. MSDS for dental technicians through education and promotion of information about chemicals and chemicals was to prevent health problems caused by the MSDS that will raise awareness of the necessity.

Objective: The purpose of this study was to research of investigation of dental technology students about health educator systems. Methods: A survey was performed on 102 subjects in March in 2010. There search tool was a structured questionnaire. The collected data was analyzed by frequency, descriptive, chi-square test and Pearson’s correlation coefficient by Statistical Package for the Social Sciences version 12.0. Results: Respondent most did not know about health educator systems. But, positive opinion for it. And necessity about education appeared high in subjects. There are a lot of interests in health educator system(p=0.000). Conclusion: We thought that interest of dental technology student's rise more.

Purpose: The purpose of this study was to analyze the career barriers of students studying dental technology in DCollege. Methods: This study targeted 490 college students studying Dental Technology in D-College. The survey about career barriers on this study consisted of 45 questions and was scored with 5-points per question. The corrected data was analyzed by SAS V8 for Windows. Results: The difference analysis of career barriers shows that differences exist depending on gender(p<.01) and serving military service(p<.05). Especially, female students(2.69) and male students(2.65) who didn't serve the military are more susceptible to career barriers. In the sub factors of career barriers, differences exist depending on and in order of gender, serving military service, experience studying one more year to enter the college, day and night, the affiliation of highschool graduated from, and hometown. The correlation between the sub factors of career barriers and perception of career barriers manifested ‘Lack of self assurance’(0.84), ‘Sense of physical inferiority’(0.76), ‘Relationship with other important people’(0.73) and ‘Lack of information on occupation’ in order. Conclusion: In the factors affecting non-decision on the career, ‘Lack of self assurance’(=0.2465) is the highest in terms of influence, followed by ‘Difficulty in interpersonal relations’(=0.1801) and 'Lack of information on occupation’ (=0.1391).

Purpose: This study was conducted to corroborate factors affecting dental technicians recognition states of their job consciousness. Methods: Self-administering questionnaires were distributed directly to some 200 registered female dental technicians in metropolis, small & medium-sized cities, farming and fishing villages of whom 153(76.5%) female dental technicians and female students responded in December, 2009. Information on recognition states of female dental technicians and female students in department of dental technology possible occupational mind and other general characteristics was gathered. Analysis of data was processed by use of X2-test and multiple regression analysis. Results: The recognition states of occupational satisfaction were higher in female students than female dental technicians(p<.05). They were observed that between respondents with more than five years of work and less than five years of career(p<.05). Statistically significant differences were observed in recognition values of female dental technicians occupational satisfaction between high and low groups of internal characteristic of their position and all ceramic part(p<.05). Conclusion: For woman dental technicians, the most predictive variables for recognition values of occupational satisfaction were an age, between groups, which of part and career(p<.05). Finally, this result suggests the facts that in order to achieve self-realization through the work experience, women herself should get rid of the dichotomous diagram and should change the consciousness of traditional role normals.

Purpose: This study investigates one production method from several production methods of the CEREC3 system which does not require model production and that can be used without antagonistic relationship and check bite and can provide one-day treatment. Methods: The ceramic inlay was produced using the IPS Empress CAD block of Ivolar Vivadent, which is a glass ceramic block, by applying the information obtained from the optical impression prior to preparation for the maxillary right second premolar and maxillary right first premolar to the optical model constructed after preparation. The optical model was not trimmed in the case of the maxillary right second premolar while parts other than the working tooth were trimmed of their optical model in the case of the maxillary right first premolar. The thin part was reinforced after installing sprue in the maxillary right second premolar, and for the maxillary right first premolar, the thin part in the optical model was reinforced with sprue to produce the ceramic inlay. Results: The processing time for the virtual prosthesis when producing the maxillary right first premolar without trimming of the optical model was slightly delayed. Both maxillary right second premolar and maxillary right first premolar were suitable for ideal prosthesis. The thin parts of the virtual restoration were easily identified through different colors and modification was simple as the thickness was described in numeric values. It took approximately 1 hour from obtaining the optical impression to oral settlement, and production of a temporal restoration was unnecessary due to the short production time. Conclusion: The CEREC3 system enabled quick production of prosthesis due to the provision of an optical impression which enabled omission of impression sampling and model production, and also precise production due to lack of contraction and expansion of materials. In this study, the slight delay in processing time for virtual prosthesis is estimated to have resulted from the size of the optical model in the software, and both prostheses exhibited suitability for ideal prosthesis. Also, treatment was possible through one-time visits which lessened the burden of patients from having to make multiple visits to the dental clinic. Meanwhile, the patients exhibited a high level of satisfaction due to the excellent aesthetics of the ceramic material. However, precision can differ in CEREC3 based on the skills of the operator. Formation of a precise cavity of the abutment tooth, manufacturer°Øs manual, space given for cement by the program, precise use of the contrast spray containing titanium dioxide, and accurate sampling of the optical impression are considered to be important factors.