This study sought to apply different MgO additions to Zirconia (20wt % Frit) and thereby determine its mechanical properties depending upon variation of temperature, as a part of elementary study. First, in terms of sintering density depending on sintering conditions, it was found that sintering density increased as temperature varied from $1100^{\circ}C$ to $1300^{\circ}C$. As the addition of MgO increased, it was found that sintering density tended to decrease at each temperature. For the maximum sintering density obtained from pellet, it was found that 3wt% MgO addition specimens sintered at $1300^{\circ}C$ had its maximum sintering density as high as 97.39%. This study measured mechanical properties of these specimens, and it was found that their bending strength tended to decrease as the content of MgO addition increased. And it was found that their bending strength reached up to 162 MPa when 3wt% MgO was added to them for sintering process at $1300^{\circ}\Delta C$. It was also found that those specimens had Vickers microhardness up to 4.6 GPa when 5wt% MgO was added to them for sintering process at $1300^{\circ}C$.

This experimental study was to determine the fitness in each cervical margin of reusing porcelain gold alloy. The gold alloy used in this experimental study was a Au-Pt-Pd alloy (BDCG-898, Bukwang Inc, Korea) for the fabrication of porcelain fused to metal crown. Twenty-five copings were divided into the five groups. And the group A, B, C, D and E were cording successively according to the frequency of reuse to five times. Each specimen was reused without adding new metal. The experimental results were as follows: 1. The group A, B, C showed good fitness in each cervical margin. 2. The group D got good fitness in labio and linguo cervical margin, but the mesio and disto cervical margin showed more than $40{\mu}m$ 3. The group E showed worse fitness than the other groups in each cervical margin.

This study was the study verifying dental technicians' motivation and job satisfaction in Seoul through the positive method as well as its purposes were to investigated the effect of dental technicians manpower supply/demand prospect on motivation, job satisfaction and the effect of other job satisfaction factors on dental technicians motivation and job satisfaction. For then, general characteristics of study objects were classified by sex, married/unmarried, age, career, salary, highest level of education, working place, position and job as well as job satisfaction factors were classified with future supply/demand prospect, future prospect, working hours, working environment and salary. We conducted a frequency analysis, crossing analysis and multi-linear regression analysis about the effect of the classified articles on motivation and job satisfaction. Also, for verifying the relationship of motivation and job satisfaction, we conducted correlation analysis and its result is as followed. First, it showed that the job related with making orthodontic appliance influenced on motivation, among the age, career and job of the general characteristics, and other jobs between working place and job influenced on job satisfaction. Second, the dark future prospect was showed to influence on motivation and job satisfaction highly so we could grasp that negative opinions are included in that. And low-paying was showed to highly influence on job satisfaction s fall so we could grasp the subjective low-salary standard at the present. But we expected that the manpower supply/demand prospect would influence on motivation and job satisfaction but there was little influence. Third, the correlation between motivation and job satisfaction was showed to be somewhat high, motivation had the standard which is above average and job satisfaction had the standard which is below the average. So with a little improving of job satisfaction, it s possible that motivation can be very high. Therefore, in rapidly changing generation, we think that the dental technicians are actively coping with the reality of low-paying and high-working. But it's implying that anxiety for uncertain future was reflected. Furthermore, because institutional strategies for dental technicians' efficient management are insufficient in relation with policies so it's necessary the policy consideration for solve the job-unsatisfying factors actively.

Purpose: The purpose of this study is dental technicians perception investigation about national health insurance of old persons denture in metropolitan area. Methods: A survey was performed on 103 subjects in metropolitan from January 14 to April 30 in 2009. The research tool was a structured questionnaire. The collected data was analyzed by frequency, descriptive and multiple linear regression. Results: Total dental technician who respond to questionnaire was 103(100.0%). Male respondent appeared by 66.0%. 30-year-old low respondent appeared by 60.2% and subjects lived the most in seoul(68.0%). When got married, was expose that realization about national health insurance of old person s denture was high(p<0.05). When made denture, was expose that realization about national health insurance of old person s denture was high(p<0.05). Also, When got married, was expose that necessity about national health insurance of old persons denture was high(p<0.001). Conclusion: When did national health insurance of old persons denture, there were a lot of problems. But, old people was need it. Therefore, I desire that this study is used to basic data of the national health insurance.

As Korea is entering an aging society, the number of elderly people who need new denture or who have problems with their existing denture or adjacent tissue is increasing and it will double in 2018. Therefore, denture clinician system will lessen patients financial burden and introduce market economy to the dental prosthesis field. Therefore, Korea needs to adopt denture clinician system as soon as possible as USA or Canada to increase people s accessibility in quality and quantity. Denture clinician will determine the size and shape of denture after performing oral examination, make impression using various materials, fabricate denture, deliver and adjust completed denture to the patient, repair denture, and carry out financial management in the denture fabricating company or manage human resources. Considering denture clinicians services, American and European education system seems to be close to our system. Therefore, in this study, basic curriculums of several countries in Europe and America were reviewed and curriculum that meets Korean situation was suggested.