Earticle

Purpose: The aim of this study was to determine the repeatability and reproducibility of two dental scanners. Methods: The master die and the stone replicas(Kavo, Germany) were digitized in touch-probe scanner(Incise, Renishaw, UK), white light scanner(Identica, Medit, Korea) to create 3-dimensional surface-models. The number of points in the point clouds from each reading were calculated and used as the CAD reference model(CRM). Discrepancies between the points in the 3-dimensional surface models and the corresponding CRM were measured by a matching-software(Power-Inspect R2, Delcam Plc, UK). The t-student test for one samples were used for statistical analysis. Results: The reproducibility of both scanner was within 3 , based on mean value. The mean value between measurements made directly on the touch probe scanner digital models and those made on the white light scanner digital models was 2.20-2.90 , and was statistically significant(P<0.05). Conclusion: With respect to adequate data acquisition, the reproducibility of dental scanner differs. Threedimensional analysis can be applied to differential quality analysis of the manufacturing process as well as to evaluation of different analysis methods.

Purpose: This study was performed to compare mechanical properties for sintering methods of porous Ti implants. Methods: The specimens of Ti implant were fabricated by several sintering methods. One of them is spark plasma sintering(SPS). Another is electro discharge singering(EDS) and the other is high vacuum sintering(HVS). Mechanical properties of porous Ti implants were evaluated by universal testing machine(UTM) and their fracture surface was examined under a sanning electron microscope(SEM). Results: The tensile strength was in a range of 71 to 230 MPa, and Young’s modulus was in a range of 11 to 21 . It matched with range of cortical bone. Conclusion: Mechanical properties of porous Ti implants were similar to human bone. It was shown that sintering methods of spherical powders can efficiently produce porous Ti implants with various porosities. Porous metals will be commonly used in orthopedic and dental application despite of initial focus has been on bioceramics

Purpose: This study compared the surface hardness (Vickers) and microstructural characteristics between a type IV stone with and without die hardening treatment, a polyurethane die material. Methods: Materials used were a type stone(MG Crystal Rock), two die hardeners (Hardening bath, Epox-it), and a polyurethane resin material(Polyluck). Six specimens per group were prepared according to manufacturer’s directions. The prepared specimens were tested by means of hardness test, one-way ANOVA analysis, scanning electron microscopic(SEM) observations and energy dispersive spectroscopic(EDS) analysis. Results: In the hardness test and its statistical analysis, there was no significant difference in the surface hardness between a type stone and type stone with die hardener coating, type stone mixed with an epoxy like material instead of water. In contrast, polyurethane resin material exhibited significantly greater surface hardness than other specimen groups (p<0.05). Conclusion: By considering the results of the hardness test, SEM observations and EDS analysis, although the die hardeners on type stone did not show remarkable improvement in surface hardness, the die hardener coating on the surface of type stone material did show decrease of microporous and improvement of surface defects.

Purpose: This study was conducted to evaluate the corrosion resistance of metal ions of alloys and use the results as the dental health data. These were performed by examining the corrosion levels of Co-Cr alloys for the full and removable partial denture metal frameworks and porcelain-fused-to-metal crown, among the dental casting nonprecious alloys. Methods: The alloy specimens (N = 10) were manufactured in 15 10 1.2 and stored in two types of corrosive solutions at 37 for seven days. The metal ions were quantitatively analyzed using the Inductively Coupled Plasma-Atomic Emission Spectrometer. Results: Of the three Co-Cr alloys, the Co ion concentration of the porcelain-fused-to-metal alloy was 1.512 / , which indicated the highest metal ion dissolution. The metal corrosion was higher in the more acidic pH 2.2 solution compared with the pH 4.4 solution. In all three Co-Cr alloys, Co ion dissolution was predominant in the two corrosive solutions. Conclusion: The corrosion resistance of the three Co-Cr alloys was high, indicating a good biocompatibility

Purpose: This study was carried out in order to examine the relationship of job satisfaction and quality of life on the dental technicians and to analyze its influence. Methods: A self-reported questionnaire survey was carried out by having convenience sampling as 220 dental technicians who work in Seoul Metropolis, Gyeonggi-do Province, Daejeon and Chungnam Province from March 12, 2012 to April 13. A research tool was used questionnaire that was proved reliability and validity. It was prepared with totally 50 questions such as 12 items for subjects’ general characteristics, 18 items for job satisfaction measurement, and 20 items for life quality measurement. An analysis of the collected data was computationally processed by using SPSS Win 17.0 program. An analytical technique was made by using statistical techniques such as frequency & percentage, T-test or One-way ANOVA analysis. The following are the analytical results of the collected materials. Results: As a result of analyzing research subjects’ job satisfaction level, there was significant difference(P<0.05) in items of religion, hobby life, working environment, and rest time out of daily work. The whole mean in job satisfaction was indicated to be relatively high with 3.13. However, job satisfaction with social recognition, salary, and safety was indicated lowly. As a result of analyzing research subjects’ life quality level, there was significant difference(P<0.05) in items of religion, hobby life, working environment, and rest time out of daily work. The whole mean in quality of life was indicated to be relatively high with 3.10. However, the satisfaction was indicated lowly in the whole life quality and the life environment sphere. As a result of analyzing correlation between job satisfaction and life quality, all variables were indicated to be positive correlation in high significance level, thereby having been indicated that the higher job satisfaction leads to the higher life quality. Conclusion: As a result of research, the dental technicians’ job satisfaction was indicated to have high correlation with quality of life. An effort is judged to be necessary for establishing fair compensation system, improving welfare policy and enhancing social recognition and position in order to promote dental technicians’ quality of life.

Purpose: The purpose of this research was to examine department satisfaction for improving the competitiveness of department of dental technology and providing basic data for students successful guidance. Methods: The study subject were 560 students from 4 colleges, and they were selected by the convenient sampling method. Data for this survey was obtain by self-administration method. This questionnaire consist of general characteristics, the awareness of before entering department of dental technology, the satisfaction of department of dental technology, an opinion about change of one’s course and temporary absence. Results: About the time of selecting their major, 70.1% of students answered the most before highschool. Department of dental technology and the most common source of information in selecting a majors is the person oneself(52.6%). The person who answers because of knowing a little bit for the question asking the priori knowledge of department of dental technology showed up as 66.3%. About the motivation for selection their major, 37.4% of students answered the most it seemed to be a future prospect. As to the extend of department satisfaction, the satisfaction showed up as 63.3%, but the extend of satisfaction was exposed to reduce as the grade increased. The dissatisfaction factor is the difficulty of the theory(29.8%). Many students do not want to change their majors even if they are provided with the chance to do so(68.7%). From the survey related to the experience of thinking over temporary absence and drop out, 56.8% of students responded they had experienced thinking about that. Current feelings after department selection was found to be the most significant factor that affects satisfaction of department of dental technology(Adjusted R2=48.3%). Conclusion: The extend of satisfaction of the women is low. The extend of satisfaction reduces as the grade increases. The school subject extend of satisfaction can know that ratio about of considering the leave of absence and voluntary withdrawal increases. Therefore, the plan of education that women can adapt the women o the school subject well and that it can be satisfied is sought for. It is considered that effort promoting the extend of satisfaction is needed as the grade increases.

Purpose: This study conducted a survey on the elderly of 65 years and over with physical debilities and ones capable of living at home residing in Jeju Special Self-Government Province to compare and analyze demosociological characteristics and factors influencing on oral health related living quality. And also this study intended to provide basic data for developing effective public medical policies and health promotion programs to increase oral health related living quality of the elder. Methods: The elderly of 65 years and over living in Jeju Special Self-Government Province were interviewed individually from 7 February 2011 to 18 April and interview results of a total of 220 subjects were analysed for this study. Results: Current status of the elderly including ones with & without physical debilities influenced functional limitation and behavioral aspects of GOHAI criteria used in this study. The eldely with physical debilities experienced less limitaion in food chewing and swallowing, and pronunciation than ones capable of living at home. On the analogy of the previous study(by Park, N. G., 2010) in which oral health related quality and satisfaction of life of the elderly with physical debilities were different due to their physical, circumstantial and psychological limitations, the former's oral health conditions are worse than the ones capable of living at home and because of medical care accessability limitation they suffer from deteriorated oral condition. By the comparison of factors influencing on the living quality relating to the oral health of the elderly with physical debilities and ones capable of living at home, 2 factors, age and living area, were meaningful factors commonly influencing on the oral health related living qualities of both. The elderly of 75 years and over were more affected by psychological and behavioral aspects of oral health related living quality than the ones of 65-74 years, and the ones living in country suffered from functional limitations, pains and discomfort more than ones in city. Additionally, being different from the elderly capable of living at home, the ones with physical debilities were influenced by the factors of average monthly income and medical security type. Conclusion: Improvement of programs and systems to increase oral health related quality of life needs to be carried out preferentially for the elderly of 75 years and over, and dwelling in country. Also this study suggests that the policy of paying the denture insurance allowance in 2012 need effective planning considering the elderly’s current status, age, living area, medical security type.

Purpose: This study was aimed to know the perception about Certified Dental Technician system of students majoring in dental laboratory technology in Korea. Methods: A survey was conducted for four months from August through November 2011 with questionnaires. The responses from 1148 students majoring in dental laboratory technology in Korea were analyzed with SPSS 12.0 program, and frequency analysis and chi square test were implemented. Results: Total students who responded to the questionnaire were 1148 (100%). The population characteristic of this survey is that 691 (60.2%) are male. The respondents believed that the job skill could be expanded by implementing the system (85.6%). Also, they responded that they would be willing to acquire the Certified Dental Technician qualifications in the future (95.5%). Conclusion: Students majoring in dental laboratory technology in Korea believed that the execution of the system of Certified Dental Technician would expand the dental technology industry.

Purpose: It is to survey old men’s utilization status of dental clinic and temporary-binding dentures and then to provide basic data to make a program for manufacturing old men’s dentures and their teeth health education. Methods: Random selection was made on old men living in Daejeon and Chungnam, and a survey was conducted from April 15 to May 20, 2011. 500 questionnaires were distributed and 420 questionnaires were collected. Using spss 18.0 program, final analysis was made on 363 questionnaires except for 57 questionnaires which had missing value or showed some doubts about the unreliability. Results: 1. With respect to number of natural teeth as per the age, the upper/lower jaws had meaningful differences (P<.001), which means that the older the person is, the smaller number of natural teeth is. In the meantime, there was no meaningful difference according to sex. 2. With respect to kind of prosthetics installed in a mouth as per the age, there was meaningful difference in the upper jaws (P<.05) but there was no meaningful difference in the lower jaws. It was found out that the older the persons are, the more they use removable dentures while the younger the persons are, the more they use fixed partial dentures. 3. With respect to mouth health condition recognized by oneself, it showed bad (44.4%) and good (10.3%),which means recognition as bad is greater, and the age when prosthetics were first used is dispersed variously from below 40 to over 70. 4. Dental care institutions which they mainly used are hospital and clinics (91.5%), and 66.4% of them visited dental clinics lately. Preferential treatment if they go to dentists is as follows in the order of prosthetics (33.9%), gum treatment (24.2%) and pain treatment (14.9%). 5. 68.4% of them revisited dentists after installation of dentures and the reason for revisit is as follows in the order of poorly fitted dentures (35.1%), painful gum 25.9%, regular check-up 25.4% and difficult chewing 9.6%. Conclusion: As our country enters into an aging society, mouth health problem of old men has come to a serious issue, and therefore, a survey was conducted on some old men with respect to their utilization status of dental clinic and removable dentures in order to provide basic data for improvement of quality of their life, maintenance and enhancement of their mouth health. The study result shows that the older they are, the higher the loss rate of teeth as well as needs for prosthetics are, and thus it is thought the study will help to develop mouth health education program which may improve quality of old men’s life by recovery of mouth functions declined due to loss of teeth and by regular check-up, education for mouth health control and following-up control of dentures.

Purpose: This study aimed to find overseas workplace and improve global competence through the preference survey on overseas employment by dental technology students. Methods: The survey sample consisted of 250 randomly selected dental technology students. Survey was conducted from March 1 to May 1 in 2012. Total of 245(98.0%) replies and analyzed 236 questionnaires excluding 9 incomplete questionnaires. The questionnaires used in this study consisted of 7 items for general information, overseas employment characteristics of 10 items, 7 items for overseas employment activation plane and job competency development of 7 items. Collected data were analyzed using SPSS(Statistical Package for Social Sciences) Win 19.0 statistics program. Results: Regarding general characteristics of the subjects, there were 131 third graders(55.5%), 63 first graders(26.7%) and 42 second graders(17.8%) among 130 males(55.1%) and 106 females(44.9%). 221(93.6%) of the subjects had no experience in language training. Students who had clinical training for 1-5 months were 123(52.1%), and 24(10.2%) students had more than six months. 89(37.7%) of the subjects had no clinical training. 155(65.7%) of the subjects hope to work with korean owner, and 81(34.3%) chose foreign owner. Favored working countries were Australia(41.5%), the United States(29.2%), Canada(18.2%) and other(11.0%). The field of dental ceramic was indicated to be the highest proportion of 104(44.1%). Period of training were 3 hours(40.3%) and 6 hours(35.2%). The most important training were language-centered education(54.2%), Joboriented education(24.2%), local culture education(16.1%), other(3.0%) and Leadership Training(2.5%). The subjects chose overseas worker(44.9%), working-level practitioner (28.8%), successfully employed dental technology graduate(19.5%a) and professor(3.4%) as an instructor. The subjects get education and training information from professor(40.3%), other(28.0%), senior(14.4%), job site(8.9%) and acquaintance(8.5%). A credit exchange(2.46 points), a joint degree program(2.46 points), and a foreign professor(2.33 points) were needed to activate the overseas employment. A kind of dental prosthesis(3.58 points), carving tooth morphology(3.38 points), and majors of dental technology(3.30 points) were indicated to develop job competency for overseas employment. Age, year, clinical training experience and company owner were statistically meaningful data among the general characteristics affecting job competency development. Conclusion: The college needs to offer variety programs such as foreign language-centered education and a local job competency development program to graduates to be connected with international workplace and employment

Purpose: The purpose of this study was to survey dental prosthesis and dental prosthesis needs of elderly for improving oral health status. Methods: The data collected from ‘The fifth Korean national health and nutrition examination survey 2010’ was analyzed in this study. Statistical analysis was done using the Statistical Package for Social Sciences version 19.0 for Windows. We determined frequencies and percentage, calculating means, and standard deviations, and determined statistical significance using cross-tabulation analysis, logistic regression analysis. Results: General characteristics showed differences in mandible fixed crown bridge needs associated with periodontal disease. General characteristics showed differences in maxillar partial and full denture with gender, age, education, perceived oral health. General characteristics showed differences in mandible partial and full denture with age, residence, education, perceived oral health. Conclusion: In order to improve oral health of the elderly, Dental prosthesis support policy and oral health policy are necessary.