Earticle

Purpose: The aim of this study is to evaluate composite resins of indirect restorations for testing of flexural strength according to various polymerization methods. Methods: Specimen was produced a total of 40 to 10 per each group with a length 25 mm, width 2 mm, thickness 2 mm using a Teflon zig. The polymerization groups were classified into four groups. The first group proceeded with light curing only(LC group). The second group proceeded with light and heat curing(LHC group). The third group proceeded with air press and light curing(ALC group). The fourth group proceeded with air press, light and heat curing(ALHC group). Each prepared group was evaluated by flexural strength test. Statistical analysis was performed by one-way ANOVA. Post-test was performed with Tukey test. Results: The lowest in the ALC group was 119.18 MPa and the highest in the ALHC group was 168.15 MPa. There were statistically significant differences. Conclusion : The composite resin of the indirect restoration is recommended to heat curing along with the air press.

Purpose: The purpose of this study is to investigate the non-precious metal core materials used in the dental laboratory to fabricate the implant superstructure by CAD/CAM method. And to observe and compare the morphology and distribution of the osteoblasts in relation to implant osseointegration. Methods: In this study, the mandibular right first molar tooth model was selected as an international standard to produce a single core. Using this model, the impression was made with the silicone rubber, the tooth model was scanned, and a single core was designed and 5-axis milling was performed. The materials used were Cobalt-Chromium and Nickel-Chromium, and the cores for dental implant top structures were fabricated according to the procedures of the dental labs. After the fabrication, the marginal area of the core was separated and cell culture experiment was performed. The osteoblast cells used MC3T3-E1, which is currently widely used. For morphological analysis of osteoblasts, cells were post-treated and observed using CLSM (Confocal Laser Scanning Microscope) and compared. Results: The cell adhesion behavior of the specimen surface measured by CLSM was uniformly distributed in specimen A (Cobalt-Chromium) than in specimen B (Nickel-Chromium). The distribution and changes of the cells were different in the two specimens. Conclusion : It is possible to confirm that specimen A (Cobalt-Chromium) is suitable for the living body through adhesion and proliferation of osteoblasts related to implant osseointegration in the non-precious metal superstructure used after implantation. It is considered that it is preferable to use Co-Cr when fabricating the superstructure.

Purpose: The purpose of this study was to investigate the production environment of crown prosthesis for National Health Insurance(NHI) benefit. Methods: This study carried out self-administered questionnaire survey from September 1, 2016 to October 31 by having research subjects as 261 dental technician. Except 100 copies with incomplete response, 161 copies were used as the materials of final analysis. Results: Unlike gold crowns, the material cost of metal crowns was paid at the dental laboratory(86.3%). Total material consumption for making metal crown was more than gold crown(63.4%), especially for the finishing and polishing processes(78.3%). The subjects responded that a routine dental laboratory fee of crown prosthesis is unreasonable, and it is necessary to adjust and improve it(metal crown 96.2%, gold crown 96.9%). NHI coverage dental prosthesis was not marked on the order form(46.0%), and the dental laboratory fee of that was nor received(64.0%). Conclusion : It is necessary to estimate the NHI cost level of the crown prosthesis by reflecting the production environment and engineering process in dental laboratories. In addition, institutional arrangement should be backed up so that dental laboratories can receive appropriate dental laboratory fee.

Purpose: The purpose of this study was to examine the influence of dental technicians sense of work ethics on their organizational effectiveness such as job satisfaction and organizational citizenship behavior. Methods: A self-administered survey was conducted from August 25 to September 15, 2017, on 220 selected dental technicians. The collected data were analyzed by SPSS Win 19.0. Statistical data on frequency and percentage were obtained, and t-test, one-way ANOVA, correlation analysis and regression analysis were carried out. Results: When the subjects' sense of work ethics was analyzed, there were significant differences according to their field of work, position, dental technician career and monthly income(p<.05). Their average score in the items about a sense of work ethics was 3.80, which was a high score. As a result of analyzing the organizational effectiveness of the dental technicians, there were significant differences according to their field of work, position, dental technician career and monthly income(p<.05). The average score in job satisfaction items was 3.14, and that in organizational citizenship behavior items was 3.55. Conclusion : As a result of research, the above-mentioned findings of the study imply that as for the correlation between a sense of work ethics and organizational effectiveness, a better sense of work ethics led to better organizational effectiveness, as every variable had a significant positive correlation with each other. In addition, interpersonal relationships were identified as the factor that exerted the largest influence on both of job satisfaction and organizational citizenship behavior.

Purpose: The purpose of this study is to provide basic data that can help the development and implementation of effective and satisfactory programs. Methods: This study was used for the analysis of 699 dental technicians attending the general conference of Korean dental technicians in 2017. Statistical analysis, t-test and ANOVA were used for the analysis. The collected data were analyzed by SPSS 24.0. Results: Satisfaction with the number of lectures in continuing education was 2.54, and satisfaction with composition of major field was 2.72. Satisfaction with the content of the lecture was 3.04. The instructor level was 2.91, and the overall satisfaction was 2.92. Satisfaction with continuing education was 2.83. Conclusion : In order to increase the satisfaction of dental technicians, we expect to have various practical and systematic education such as diversification of education methods, quality level management, online continuing education.