Earticle

Purpose: The aim of this study was to compare with color reproducibility of the coating method and dipping method using a colour liquid. Methods: Two groups of square-shaped specimens (10 10 in diameter, 1.5 thickness) were prepared for analysis(n=15/group). The CM(Coating Method) group was fabricated as full zirconia specimens with the coating coloring method and Group DM(Dipping Method) was prepared as specimens of 0.7 mm-thick zirconia plate using the dipping coloring method and veneered with 0.8mm-thick porcelain. Color parameters were measured with ShadeEye NCC spectrophotometer and color differences were calculated using the equation E* = {(L*)2+( a*)2+( b*)2}1/2. Non- parametric statistical methods, the Mann-Whitney test, and the Kruskal-Wallis test were used to analyze the data. Type one error rate was set at 0.05. Results: Color difference values larger than 7 were observed between specimens with the coating method and the dipping method, which were detectable difference in a clinical setting. Conclusion: Cautious application of the coating coloring method in a clinical setting and further researches to standardize the coating method are needed.

Purpose: In this study, in order to provide objective standard of the mixed concentration of the zirconia coloringliquids,compare the shade differences after colored zirconia blocks from different concentrations. Methods: After immersion for 2 minutes zirconia specimen (1.5 1.5 0.6 0.01 ) in coloring-liquids that produced different concentrations, were sintered in furnace dedicated. Then, it was measured in spectrophotometer and Shadepilot. It has been determined mean and standard deviation of the color difference for each group, and verified by one-way ANOVA using the (version12.0) SPSS WIN Program the difference in shade according to the concentration at the significance level of 95% confidence, it conducted a Tukey’s multiple range test to post-test. Results: The mean of L* was decreased toward LN35 group, however the mean of a and b was increased(p<.05). There is a statistically significant difference in the results of L post hoc test of each group was LN15-LN30/LN35,LN20-LN30/LN35, LN25-LN30/LN35, and LN30-LN35 group. The a* group, it was found that there is a statistically significant difference in all groups for each(p<.05). The b* group, it was found that there is a statistically significant difference in all groups except the LN25-LN30(p<.05). Conclusion: In order to make effective use of the coloring-liquids of zirconia, the device objective, accurate concentration measurement is required, from the present study, we presented evidence basic to this.

Purpose: In this study, the loosening torque test was conducted with three implant products that are produced,approved and sold in Korea, which are manufactured in different fixture and abutment tightening methods (internal submerged type, internal morse taper type, and external type) to examine the loosening torque of the screw according to the method of tightening the implant fixture and abutment. Methods: In the loosening torque test, the three types of fixtures and abutments with different tightening methods were tightened by rotating them clockwise with a 30 N force using a driver equipped with an electric torque meter. The results of the test are as follows. Results: The loosening torque values of the internal submerged type, internal morse taper type and external type implants were 24.10 0.742 N , 29.10 1.710 N , and 26.60 1.636 N , respectively. Conclusion: The screw loosening torque values of the three fixture and abutment tightening methods were analyzed via Kruskal Wallis test layout, and they were significantly different (p<0.05).

Purpose: The purpose of this study was to know the availability of two photosensitizers, PD, DA, as a photosensitizer instead of CQ in UDMA dental composite resin. We want to know photopolymerization effect of UDMA unfilled resin and surface hardness of composite resin containing PD and DA were compared with those of CQ, most widely used photosensitizer for dental composite resins. Methods: The photopolymerization effect of UDMA studied by FT-IR spectroscopy increased with irradiation time and the amount of photosensitizer. Knoop hardness of experimental composite resins prepared by the addition of the photosensitizer content and irradiation time. Results: The relative photopolymerization effect of UDMA increased in the order of PD > CQ > DA. The composite resin of UDMA containing DA or PD, which shows better Knoop hardness than that containing CQ. Conclusion: PD and DA show as effective photosensizers, suitable for UDMA dental composite resin compare with a higher efficiency than CQ.

Purpose: The purpose of this study was to investigate the image and the awareness of dental laboratory technicians in health allied college students. Methods: The subject of this research are 431 health-related major students who are selected by convenience sampling from Seoul, Gyeonggi-do, Chungcheong-do, Jeolla-do and Gyeongsang-do. After a survey was conducted,the answer sheets from 401 respondents were analyzed except for 30 incomplete ones. The collected data is statistically analyzed by SPSS(Statistical Packages for Social Science 12.0. SPSS Inc., Chicago, IL, USA). Results: The findings of the study were as follows: As a result of general awareness about dental laboratory technicians, the health allied college students knew 83.0% about dental laboratory technician as a job. Respondents showed high recognition about dental laboratory technician as a job(3.62 0.31), which showed that the health allied college students took a favorable view of dental laboratory in general. There were significant difference in dental laboratory technician image with age, gender (P<.05). Conclusion: It is required to develop programs such as proactive public relations or campaign via mass media that could enhance the public recognition about dental laboratory technician up to one of professional as required. It is also necessary that dental laboratory technicians make steady efforts for self-development to enhance their own job philosophy and skills in the level of quality, while they need various educations for building up their own favorable personality and positive ideas

Purpose: The study is to discover the relationship between malocclusion, which is known to cause temporomandibular disorder, and temporomandibular disorder and is aimed at college students who have retained their natural teeth. Methods: The study was aimed at 500 college students at two colleges located in Gyeongsangbuk-do and Daegu metropolitan city and survey research was conducted in order to discover any relationship between malocclusion and temporomandibular disorder. After excluding copies with insincere answers or errors out of the 500 copies of the questionnaire, the study used a total of 435 copies (87%) for research and analysis. Results: Females showed a prevalence of temporomandibular joint clicking and temporomandibular joint pain,and students who had crowding showed a high prevalence of temporomandibular joint pain, temporomandibular joint clicking, and trismus. Students whose occlusal condition was not good demonstrated a high prevalence of temporomandibular joint pain, temporomandibular joint clicking, and trismus. Students who had maxillary protrusion showed a prevalence of temporomandibular joint clicking and trimus, whereas students who had mandibular protrusion showed a high prevalence of temporomandibular joint clicking. Conclusion: Students whose dental condition was crowding and students whose occlusal condition was not good exhibited a high prevalence of three types of symptoms of temporomandibular disorder. Meanwhile student who had maxillary protrusion showed a high prevalence of temporomandibular joint clicking and trismus, while students who had mandibular protrusion showed a prevalence of temporomandibular joint clicking.

Purpose: This study aims to analyze the factors affecting the dropout intentions of the dental technology students of a college. Methods: The subject of this study was 76 freshmen and 74 sophomores of dental technician major in an anonymous college. Results from the questionnaire called K- vision diagnosis program were computed by means of t-test, One-Way ANOVA, and correlation analysis. Results: 1. Total points of the drop out intention came to 782.14 points. Of the five categories concerned with the drop out intention, complain in college satisfaction (50.12points) was the highest and department satisfaction(47.51points) was the lowest. Of 16 subcategories, complaining in administrative supporting system proved the highest as 50.80 points and Inquiry to Professor the lowest(45.56 points). 2. Among the general characteristic gender (p<. 01), student group (p<.01), and credit (p<.05) made a meaningful statistical difference; no statistical significance was found in grade, admission, and dwellings. 3. Of the five categories, statistical significance was shown as follows; Department satisfaction (p<.01), College satisfaction (p<.05) under gender, Department satisfaction (p<.05) in grade, Academic integration (p<.01), Department satisfaction (p<.01) in credit. No statistical meaning was found in admission and dwellings. 4. Statistical significance was found under 16 subcategories as follows: Career identification(p<.01), Academic support system (p<.01), Social activity II(p<.05) in gender area,Inquiry to professor(p<.01), Learning (p<.05), Understanding learning I(p<.05) in grade area, Learning(p<.001),Career identification(p<.001), Understanding learning I(p<.01), Understanding learning II (p<.01), Inquiry to professor (p<.01), Learning ability (p<.05), Occupation (p<.05), Social Activity II(p<.05), Administrative support system (p<.05) in student group area, Credit (p<.001), Career identification (p<.01), Understanding learning I(p<.05) in credit area; admission and dwellings was statistically meaningless. 5. Of the 5 categories academic integration (r=.766) was most relevant to the dropout intention of the subjects and followed by department satisfaction (r=.735), college satisfaction (r=.554), service acceptability (r=.373), and statistical significance was shown as p<.01. Conclusion: Considering the results of this study, we are in a pressing need for the introduction of policies and programmes aiming at preventing the dropout rates of the dental technician majors at college. In tandem with this,qualitative and viable human resource management of the dental technicians should be implemented.