Earticle

Purpose: The purpose of this study is to investigate the level of each metal in non-precious metal alloys dental casting, still used even banned for use and trade by the law, for oral health. Methods: Two kinds of metal alloys were analyzed. One was Ticonium 100 for removable prosthesis and the other was Rexillium V for dental porcelain. Two samples of each metal alloy were made in 0.5g, 1.0g, and 1.5g. Total number of samples were 12. Two kinds of lactic acid Solution, pH7 and pH4.6, were injected into each samples. After injection, each samples had been for 21days 1 hour in the water tank of which temperature was 37 . The level of metal was measured in each sample by inductively couplled plasma-atomic emission spectrometer. Results: In both metal alloys, metals, chrome, nickel, beryllium, and molybdenum, were founded. In Ticonium 1000, the highest level of nickel was 2.531ppm in 1.5g pH4.6 sample while the highest level of nickel was 4.062ppm in 1.5g pH4.6 sample of Rexillium V. In chemical composition of these methal alloys, chrome(14~17%) was much more than beryllium(1.95~1.99%) and molybdenum(5.0~9.0%) but berllium and molybdenum were founded more than chrome in samples. Therefore, chrome showed better anti-corrosion than other metal alloys. In both metal alloys, more metals were founded in higher pH level and more mass. Levels of chrome was significantly different in samples of both metal alloys in each pH level(p<0.05). Levels of nickels was significantly different in samples of both metal alloys in each pH level(p<0.05). Conclusion: For oral health, further studies are needed in nickel-chrome metal alloy and cobalt metal alloy of non-beryllium in addittion to beryllium metal alloy and also long-term studies needed in various period and other non-percious metal alloys for dental casting.

Purpose: The purpose of this study was to investigate the transmittance differences of zirconium core due to thickness within the visible light spectrum. Methods: 36 specimens were divided into 3 groups (0.6 , 0.8 , 1.0 ) which have each 12 specimens. The size of specimens was 10 high and 10 wide. The transmittance of specimens are measured by spectrophotometer Model Cary 500 that can measure infrared-ray, visible wave and ultraviolet-ray. Results: The results shows that there was no significant difference between specimen’ thickness and transmittance. Conclusion: The individual's color perception is personal and there are numerous factors that influence on it. In general, human eye can perceive the color of thing only within visible light spectrum but in this experiment through spectrophotometer there was no big difference between specimen’ thickness and transmittance. To sum up, The most important factors were a layed porcelain structure and its thickness rather than core thickness in the porcelain crown.

Purpose: To evaluate the accuracy of zirconia copings in terms of clinical verified for the clinical application of CAD/CAM. Methods: Zirconia copings (n=5) were prepared using CAD/CAM system and were sintered using the relevant electrical induction furnace, which uses a 2h sintering program with a maximum temperature of 1500 . The copings placed at the models and the interval values were measured. Results: The meas interval values between the die and the zirconia copings were 44.14 (A), 44.57 (B), 44.72 (C). 51.05 (D). Conclusion: The maximum interval values between the die and the zirconia copings were 51.3 which is acceptable for clinical use. Proper understanding of the test conditions will help enhancing the accuracy of zirconia coping.

Purpose: The author performed experiments on the microhardness and the marginal fitness of composite resins after polymerizing 4 kinds of composite resins on MOD standard specimens. Methods: For this study, in order to compare the microhardness and the marginal fitness of 4 kinds of composite resins. Results: The results are as follows. 1. In case of the microhardness, Tescera scored the highest among the four kinds of composite resins. 2. In case of the marginal fitness, Premise Indirect scored the highest. However, there was no statistically significant difference, all staying in clinically practical range. 3. Considering the above results, among the four kinds of composite resins, the author advises to use Tescera during teeth restoration which scored the highest in the micro- hardness. Conclusion: Conclusion: All of the composite marginal fitness were within the clinically useful range.

Purpose: This study were to analyze satisfaction with job ability development training among Dental Technicians’ examine the degree of their actual satisfaction with training courses and their status, and provide some basic data to help improve the quality level, satisfaction, and effective operation of job ability development training in the future. Methods: This study carried out self-administered questionnaire survey from January 15, 2011 to March 10 by having research subjects as 180 dental technicians who participated in the course of employees’Job Ability Development Training by ‘il Occupational Training Institute,’which is being conducted as part of dental technicians' job ability development in Seoul region. Among these things, 160(88.8%) copies were collected. Except 19 copies with incomplete response, 141(78.3%) copies were used as the materials of final analysis. Results: First of all, as a result of grasping the whole satisfaction with training according to general characteristics, the significant difference was indicated in the whole satisfaction with training depending on gender & age, and voluntary participatory intention. Second, the satisfaction with contents of Job Ability Development Training was in order of helpful level in ability development with 4.10( .70), co-worker's recommendation and a plan for reparticipation with 4.08( .77), consistence with the content goal with 4.07( .71), and reflection of demand with 4.01( .70). Third, examining satisfaction with instructors of Job Ability Development Training, it is being indicated with a little higher score compared to the satisfaction with other items. Fourth, satisfaction with service of supporting learners in job ability development training was shown to be slightly low in all the items. Especially, the convenience of administrative procedure was indicated to be the lowest with 3.52( .92) Fifth, satisfaction with the facility of job ability development training was showing very low satisfaction compared to other satisfaction items. Conclusion: A continuous effort will be needed in order to be possibly strengthened dental laboratory technicians’Û professionalism and reinforced qualitative level in major ability through offering more educational opportunities and education in good quality.

Purpose: This study was to seek the application after fostering the dental technician with the disability. The purpose of this was to suggest basic data to enhance employment for the disabled by fostering dental technician with disability through the opinion of experts. Methods: For this aim, this study made the literature research using precedent research data implemented by related departments and fields and domestic & foreign literature including the reports on the status of the disabled. Results: On the base of the findings the conclusion was deduced as following. It needs to open dental technician training curriculum with disability to enhance employment for the disabled and smoothness and qualification for the practical demand and supply of the dental technician. Conclusion: To foster the dental technician with disability, there needs the change of negative view that the disabled will not be able to do well. The disabled also can do the work well as those without disability if they get the education and the training.