• Journal of Technologic Dentistry
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• v.6 no.1
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• pp.31-86
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• 1984

The educational purpose of a junior college is believed to be to effectively train and produce professional workers equipped with the knowledge and skills required in various technical fields of modern society. Since dental technology takes its share of an important role through the enhancement of people's health and the construction of a whlfare society, the prosthodontia department is imposed with a great responsibility to train highly skilled, responsible dental technicians who will meet the social demands. To attain this goal, those who are in charge of the training and education should place emphasis on the development of better educational programs. In other words, the present curriculum which is lacking in many comprehensive aspects, is not satisfactory to provide the students with the required know-how and qualities. As is known, a currculum is the detailed guidance to the efficient operation of an educational program, and that of dental technology is not an exception. In addition, dental technology requires very detailed programs in training, because it requires both diversified and comprehensive application of serveral different fields. The following are the main points to be taken into consideration in developing an effective curriculum for this department. 1. The curriculum should be gradually expanded so that the fundamental subjects will contain principal theories which can be directly applied to the specified majoring subjects. 2. An effective arrangement of time tables should be provided so that basic practice and experiments can be conducted in direct connection with the leatures on the basic theories. 3. For a creative and up-to-date curriculum to help cope with the problems in achieving the aims of technological development and scientific education, intensive and extensive studies should be done on the curricula developed in the advanced countries. 4. The specific majoring subjects should be rearranged to contain new theories which are beneficial to dental technology. As an institution which is spearheaded for ondustrial-educational cooperation, the Junior collegeis role demands that the department should make every possible effect to cultivate highly-skilled technicisns. The following suggestions are made to help work out an ideal curriculum. 1. The basic theory subjects should be selected with consideration toward closely related majoring subjects. 2. The curriculum should be efficiently operated to effectively relate theories with experiments. 3. Subject importance must be rearranged ; It has been found that the ideal proportion of cultural, elective and required subjects is 20%, 20% and 60% respectively. 4. The credit allotments should be reconsidered: The total credits required for completion should preferably be 80; 16 for the cultural and the elective subjects respectively and 48 for the required subject. 5. A Commissioned education system should be formalized for strengthening industrial educational cooperation. 6. Experiments and practice should be intensified with the support of improved laboratory facilities. 7. The training period should be expanded form the present two years to three of four years, in order to produce more highly qualified technicians.

• Journal of Technologic Dentistry
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• v.29 no.1
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• pp.93-101
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• 2007

The purpose of this study is to evaluate the effect of three different oblique mechanical loading to occlusal surfaces of posterior implant partial dentures on the stress distributions in surrounding bone, using 3-dimensional finite element method. A 3-dimensional finite element model of a posterior implant partial dentures composed of three unit implants, simplified 3 gold alloy crown and supporting bone was developed according to the design of AVANA self tapping implant for this study. Three kinds of surface distributed oblique loads(300 N) are applied to following occlusal surfaces in the three crowns; 1) All occlusal surfaces in the three crown(load of 300 N was shared to three crown), 2) Occlusal surface of centered crown (load of 300 N was applied to a centered crown), 3) Occlusal surface of proximal crown(load of 300 N was applied to a distal proximal crown). In the results, 141 MPa of maximum von Mises stress was calculated at third loading condition and 98 MPa of minimum von Mises stress was calculated at first loading condition. From the results, location and type of occlusive loading conditions are important for the safety of supporting bone.

• Journal of Technologic Dentistry
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• v.21 no.1
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• pp.15-26
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• 1999

This study was carried out by observing to composition of oxide on the surface of dental porcelain low gold alloy with various Indium additions according to the degassing and analysing the change composition of additional elements In on diffusion behaviors of Porcelain-matal surface. The specimens used were Au-Pd-Ag alloys by small indium addition. These specimens were treated for 10min at $1000^{\circ}C$ in vacuum condition. To investigate the microsturcture of oxidized alloy surface, SEM and EDAX were used, and EPMA were used to investigate the diffusion behaviors of porcelain-metal surface. X-ray diffraction were used to observe the morphological changes in the oxidation zone. The results of this study were obtained as follows ; 1) The hardness of alloy increased with increasing amount of In addition. 2) The formation of oxidation increased with increasing In content after heat treatment. 3) Diffusion of indium elements increased with increasing In content in metal-porcelain surface after firing. 4) The oxidations of alloy surface were mainly $In_2O_3$.

• Journal of Technologic Dentistry
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• v.34 no.2
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• pp.95-103
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• 2012

Purpose: Fracture strength of all-ceramic 3-unit fixed partial dentures manufactured by CAD/CAM and copy-milling systems were evaluated. Methods: Zirconia cores were made by milling the pre-sintered zirconia block by CAD/CAM or copy milling method followed by subsequent sintering. By building-up the corresponding porcelains on the core, all-ceramic bridges were fabricated, and those were evaluated in comparison with PFM fixed partial denture. Results: During the flexural test of the 3-unit PFM bridge, the porcelain started to chip or break at 507.28(${\pm}62.82$)kgf and the metal framework did not break until the maximum load level of 800kgf which was set in the testing instrument of this study. However, among all-ceramic restoration test groups, Everest(EV) group showed a peeling off or breakage of the porcelain from 365.64(${\pm}64.96$)kgf and the core was broken at 491.77(${\pm}55.62$)kgf. Those values of Zirkonzahn(ZR) were 431.03(${\pm}58.47$)kgf and 602.74(${\pm}48.44$)kgf, respectively. The break strength of the porcelain of PFM(PM) group was significantly higher than that of EV (p<0.05) group and there was no significant difference when comparing to that of ZR (p>0.05). ZR group showed higher break strength than that of EV group however there was no significant difference (p>0.05). The break strength of cores were in the increasing order of EV < ZR < PM (p<0.05). Conclusion: We could find that even though the PM group fractured at much higher value than all-ceramic cores, the breakage values of the porcelain of PM group with crack formation or delamination, which will be regarded as clinical failure, was significantly higher than that of EV group and not significantly higher than that of ZR group at p-values of 0.05. The break strength of ZR group was higher than that of EV group at an insignificant level(p>0.05).

• Journal of Technologic Dentistry
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• v.30 no.1
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• pp.49-55
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• 2008

In this study, to provide the fundamental data on stable connection method for successful implants prosthesis, We fabricated the solder joint of gold alloy bar specimens by gas flame soldering method and laser welding and soldering method. It compared and studied the tensile strength of two soldering method by universal testing machine. The results using universal testing machine were as follow : The mean of tensile strength of solder joint bar in gas flame soldering method specimens was 363.89 $\pm$17.62 MPa, and the mean strength of laser welding and soldering method was 125.91 $\pm$ 19.66 MPa, so gas flame soldering method was better than laser welding and soldering method and the finding better way to improve tensile strength is needed in laser welding method. On weak loading condition and the part which is needed an accuracy, laser welding method is more effective and on long-span prosthesis and frequent chewing loading part, laser welding technique is recommended first and applying additional gas flame soldering technique would be better for making much more successful prosthesis.

• Journal of Technologic Dentistry
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• v.26 no.1
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• pp.209-216
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• 2004

The purpose of this study is to introduce how to make implant supported over denture with Oring. Many kinds of attachments have used to dental restorations. The application of attachment has widely increased implant fixed prosthesis and implant supported over denture. In order that implant supported over denture have properly retention, generally used O-ring, magnetic, bar attachment. O-ring give us an advantage that is required more minimum vertical dimension than bar-type and easily replace with new part. When we make these prosthesis using O-ring, Bar, Ball attachment, we should following procedures. Strong occlusion force leads to fracture of over denture because part of functional mechanism as implant abutment or attachment is spaced. Clips are regularly activated. O-ring and springs are changed every year. The pattern of resorption should be carefully monitored and compensated for by relining procedures. If the over denture appears to rest on the bar or the ball attachments, relining should be performed and clips/caps should be changed.

• Journal of Technologic Dentistry
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• v.23 no.2
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• pp.105-119
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• 2002

This study was designed to grasp the degree of job stress affecting dental technicians and the degree of the symptoms of their job stress. With this in mind, the researcher selected a total of 170 dental technicians living in Seoul and Incheon, conducting a research in a period ranging from August 1,2001, to August 20, 2001. The researcher made use of a structured questionnaire whose reliability and feasibility are proved. The questionnaire is composed of a total of 55 questions: thirteen questions related to the subjects' general characteristics; 28 questions connected to the measurement of job stress and fourteen questions linked with the measurement of job-stress symptoms. The researcher analyzed the findings with the aid of SPSS(Statistical Package for Social Sciences). The research came to draw the following conclusions on the basis of frequency, percentage, T-test, and F-test, multiple regression. I. The analysis into the job stress of the subjects indicates that there is a significant difference in difficult questions among their work places, working hours, academic background, job satisfaction and jobs(P<.05). The job stress stands at 3.48 on the average, and the area of conflict among too much work and job performance turns out to be highly perceived. 2. The analysis into the degree of the symptoms of the job stress of the subjects shows that there is a significant difference in work place, working hours, job satisfaction and the continual maintenance of job(P<.05). The symptoms of job stress accounts for 2.65 on the average. Physical symptoms turn out to be highly perceived; The response 'My arms and legs are killing me' proves to stand for 3.03. 3. The correlation between job stress and the symptoms of job stress turns out to be significant(r=0.519, P<0.001), and there is a significant correlation between the average points of each job-stress area and the average points of the symptoms of job stress. All in all, it is necessary that dental technicians themselves should make positive efforts to control and relieve stress and that more efficient programs should be implemented with a view to dealing with stress.

• Journal of Technologic Dentistry
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• v.15 no.1
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• pp.43-61
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• 1993

This study was conducted to determine factors influencing dental technicians recognition level of their occupational disease. After self-administered questionnaire were distributed by mail to 540 technicians clustered samplely semplely selected from dental laboratories resistered in seoul and pusan Korean Dental Laboratory Association 395 technicians responded from march 29 through April 27, 1993. The results are as follows. 1. The recognition level of an occupational disease of the total 395 respondents by sex is higher among male than female. The difference was found to be meaningful(p <.05). 2. When the recognition level of an occupational disease being tested with 45 as the highest point possible, the average point 31.41 $\pm$ 6.50 of the total respondents reflected a high level of recognition. The highly recognized items were stress, bronchial disease, hearing loss. 3. With the highest points in Wallston and Wallstons' health locus of control in personality being 54, the average points of the dental technicians in the study was 35.41 $\pm$ 4.93. 4. As for the medical care patterns, the rate was higher among local medical insurance 64.4% than none 16.8%, company medical isurance 9.2%, medical aide 6.7%, others 2.6%. As for the experience of utilization of outpatient servelies, Yes was 40.4% and 59.6%, showing a meaningful difference(t=.80, p<.05).01) accounted total variance of the factors influencing dental technicians recognition level of their occupational disease(p<.0.000), R-squaire is 0.08.

• Journal of Technologic Dentistry
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• v.26 no.1
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• pp.129-138
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• 2004

The organization to which we belong is the place where we make social relationships, satisfy our desires of self-realization, and accomplish our common object. The emotional and psychological state of individual as well as the whole organization is able to be explained in the concept of morale. The researcher selected a total 238 dental technicians living in seoul, and conducted a research in a period ranging from April 1, 2004, to April1 10, 2004. The researcher analyzed the findings with the aid of SPSS (Statistical package for social sciences). The researcher came to reach the following conclusions on the basis of frequency, percentage, T-test, F-test, and multiple regression. The results of this study were as follows: First, there is a significant difference in recognizing morale due to their age, academic background, their work places, position, part of objective, and working hours(p<.05). Secondly, The researcher there is a significant difference in recognizing due to their social welfare, payment, fair and objective personnel management, enough opportunities of self development, and autonomy(p<.05). Lastly, this study is very limited in generalization because it deals with a small part of morale management plans and objectifies very limited organization. But, it is very meaningful in trying to approach morale management plans with an object of dental technicians. It is necessary that dental technicians should make efforts to control themselves.

• Journal of Technologic Dentistry
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• v.20 no.1
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• pp.61-89
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• 1998

Having taken as cause of dental technicians separation from their service a variety of individual idiosyncrasies, function-related factors, external environment factors, functional satisfaction, organizational commitment, and intention to remain, the present study conducted a mail questionnaire poll and interviews on those dental technicians who are mow in the service with private dental technical workshops and dental technical workshops in general hospitals and private dental clinics. The resultant findings from analysis of the repondent's general characteristics of cause of separation form service were revealed, as follows : 1) It was shown that the higher the academic career, the considerably higher cause of position commitment among causes of individual idio-syncrasies, reflecting a statistically significant result(P<0.05) 2) The less the number of working hours as viewed from the average number of working hours per day, the higher the positive emotion, reflecting a significant relation(P<0.01) 3) Causes from performing duties among function-related causes diclosed a statistically significant relation among marital status, career, monthly income, and positions(P<0.01) 4) Causes from wages showed a statistically significant relation in the average number of working hours per day(P<0.01), monthly income(P,0.05), and positions(P<0.05) 5) Causes from supervision exposed a significant relation in workplaces(P<0.01) 6) Causes from promotion represented a significant relation in positions(P<0.001) 7) Causes from opportunnities for taking a job as seen from external environment causes also disclosed a statistically significant relation in workplaces(P<0.05) 8) Reponsibility for family sustenace reflected a statistically significant relation in sex, age, marital status, career, monthly income, work fields, term of employment, positions, and experience of separation(P<0.001) 9) Functional satisfaction showed a statistically significant relation in marital status, career, monthly income, and the average number of hours a day(P<0.05) 10) Oraganizational commitment disclosed a statistically significant relation in work experience, monthly income, term of employment, positions(P<0.05) and the average number of working hours a day(P<0.001) 11) The intention to remain indicated a statistically significant relation in age, marital status, work experience, monthly income, positions(P<0.001) and term of employment. the average number of working hours a day(P<0.01), and in the performing work field(P<0.05)