Earticle

Purpose: The aim of this study was analyzed by comparing the effect of glass fiber reinforcement addition on the strength of resin denture base. It was intended to provide a reference data useful for clinical application. Methods: The test specimens (length 64.0 0.1 , width 10.0 0.1 , thickness 1.0 0.1 , 1.5 0.1 , and 2.0 0.1 respectively) were made. In the experimental groups resin denture base reinforced with glass fiber were fabricated. In the control groups resin denture base were fabricated by conventional method. After specimen fabrication was completed, transverse test was performed using a universal testing machine. Results: The transverse strength value in CON group was 83.08 9.07 for 1.0 mm, which ranked the highest in value. On the other hand, the value was 56.07 5.15 for 2.0 , which ranked the lowest in value. And CON+SES group was 119.80 30.70 for 1.0 , which ranked the highest in value. On the other hand, the value was 84.00 7.97 for 2.0 , which ranked the lowest in value. Also, the flexural modulus value in CON group was 2,983.10 506.92 for 1.0 , which ranked the highest in value. On the other hand, the value was 1,257.64 230.48 for 2.0 , which ranked the lowest in value. And CON+SES group was 4,679.41 1578.29 for 1.0 , which ranked the highest in value. On the other hand, the value was 2,512.36 527.09 for 2.0 , which ranked the lowest in value. Conclusion: The reinforced glass fiber increased the strength of resin denture base, effected to reduce the thickness of resin denture base.

Purpose: Generally dental technicians clinically decide the sintering temperature of zirconia artificial teeth to match the color of the teeth. However, the sintering temperature influence the microstructure and mechanical strength of ceramic body. In this study, to evaluate the free choice of sintering temperature which leads to color the problems in zirconia false teeth, the variation of microstructure, mechanical strength, and colortone of zirconia ceramics according to the change of sintering temperature was investigated. Methods: Bar type specimens were prepared from commercial zirconia blocks by cutting and polishing into 0.8 cm(L) x 1.0 cm(W) x 4.8 cm(H). Specimens were fired from 1,400 to 1,700℃ at 50℃ intervals and held for 1hour at highest temperature. Apparent porosity, water absorption, firing shrinkage, bulk density, bend strength, whiteness were tested. Microstructures were observed by SEM. Results: When fired above 1450℃, all specimens showed 0% apparent porosity and water absorption, 20% firing shrinkage, and 6.1g/cm2 bulk density regardless of firing temperatures. SEM photomicrographs showed grain growth of zirconia occurred above 1,600℃. Whiteness was also largely changed above this temperature. Maximum bend strength of 1,050 MPa was obtained at 1,550℃. Bend strength lowered slightly above this temperature and showed 950ßÁ at 1,700℃. Conclusion: In order to fit the colortone of zirconia artificial teeth, arbitrary choice of firing temperature higher than 1,500℃, up to 1,700℃ did not influence the mechanical strength.

Purpose: The purpose of this study was to analyze and compare the relative accuracy of digitized stone models of lower full arch, using two different scanning system. Methods: Replica stone models(N=20) were produced from lower arch acrylic model. Twenty digital models were made with the white light and blue LED(Medit , Korea) scanner. Two-dimensional distance between the landmarks were measured on the Delcam CopyCAD (Delcam plc, UK). Independent samples t-test was applied for comparison of the groups. All statistical analyses were performed using the SPSS software package (Statistical Package for Social Sciences for Windows, version 12.0). Results: The absolute disagreement between measurements made directly on the two different scanner- based dental digital models was 0.02~0.04mm, and was not statistically significant(P>0.05). Conclusion: The precision of the blue LED optical scanner was comparable with the digitization device, and relative accuracy was similar. However, there still is room for improvement and further standardization of dental CAD technologies.

Purpose: The purpose of this study is to investigate the improvement measure of dental technicians practical examination system. Methods: The subjects in this study were 290 dental technicians who were self-written questionnaire. The results were analyzed by SPSS 16.0. The collected data was analyzed by frequency and chi-square test. Results: Dental technician practical exam feasibility of survey were largely negative views. Articulators work required in practical exam as a tool used (28.7%), electric wax carver (19.5%), heating clear (17.8%), handpiece (16.2%) had a response. Dental Technician positions in accordance with practical exam in comparison to satisfaction, the professor is satisfied, but the clinical dental technicians were generally dissatisfied (p<0.05). Conclusion: Based on the results of this study, Current is necessary to analyze the practical test. It also should be compared with foreign institutions. Long-term and short-term improvement examination system that can be applied to the improvement of the dental technician to draw practical test it is necessary to improve the system.

Purpose: The purpose of this study is to investigate the improvement measures of dental technician practical examinations. Methods: A survey was performed on 37 professors through a questionnaire. The results were analyzed by SPSS 12.0. The collected data was analyzed by frequency and the chi-square test. Results: The education compared to the satisfaction of practice examinations only differs in the method of enforcement(p<.05). The evaluations on the ability to perform the job with practical subjects were inadequate (37.8%). Questions with the most necessary work tools through the articulator was highest at 48.7%, Electric wax carver was 32.4%, and heating clear was 3.5%. Conclusion: There must be an improvement to increase the cooperation within the clinical department, while considering the practical exam environment.

Purpose: Recently our country is rapidly aging population is growing. In the oral cavity of the elderly status of oral health-related quality of life to evaluate any impact. Methods: The survey used structured self administered questionnaires from April to May in 2011 in Daejeon and Chungcheong provinces to 277 people, analysis of the general characteristics of a frequency analysis method, the difference between the quality of life T / F test, whether oral self-according to the quality of life healthy oral health effects of the multiple regression analysis. Results: Award comes on the number of residual value, lower age all the more, smaller monthly income was small, but significant difference between them was no difference between gender. Residual value according to the number of differences in the quality of life of physical pain upper, physical disability, the lower the physical pain, physical disability, psychological disability were significant differences in degradation. Depending on oral maxillary prosthesis fitted to physical pain, psychological discomfort, physical disability, the lower the functional limitation, physical pain, there was a significant difference in physical disability. Conclusion: Status of the oral cavity of the elderly factors affecting the quality of life remaining in the lower dimensions, upper and lower prosthetics, self-aware state of oral health in order to improve the quality of life of elderly oral health education to be strengthened to increase the residual value, reducing their own prosthetic perceived oral health is health, so they feel it should be for the development of health education programs for the elderly should be.