Earticle

The purpose of this study was to evaluate the titanium castability with a spin typecasting machine(TiCast, Super R, Selec, Osaka. Japan). We tested phosphate bondedinvestment “Rematitan�Plus(Dentaurum, Inc., Pforzheim, Germany)”of mesh grid patternand plate pattern. Four different mold temperatures(room temperature, 200℃, 400℃and600℃) were prepared for the present study. In mesh grid pattern with spruing of φ0.88㎜dimeter, when the mold temperature increased, high percentage of castability was gained.Mold temperature showed a highly significant(p<0.05) correlation on the castability, Inplate pattern, the higher the mold temperature during casting, the greater the adhesivephenomenon between Ti surface and the investment.

The effect of Nb on interfacial bonding characteristics of Ni-Cr alloy for porcelain fused tometal crown (PFM) has been studied in order to investigate oxide layer. A specimens of Ni-Cralloy, which is 0.8mm in thickness, within the porcelain furnace of 1,000℃with four testssuch as air, vacuum, air for 5 minutes and vacuum for 5 minutes in order to examine an oxidebehavior of alloy surface generated by the adding of Nb to be controlled at a rate of 0, 1, 3and 5. Oxide film was observed form of the fired specimens with scanning electron microscope(SEM), and at the same time it measured Electron Probe Micro Analyzer (EPMA). The result of this study were as follows:1. Cr oxide film and Nb oxide film were observed from the surface of specimen to becontrolled at a rate of Nb 1%.2. Nb oxide film was observed from the interface of specimens to be controlled at a rateof Nb 1% and 3%.3. The stability of oxide films that treated in air were more stable than treated under vacuum.

The physical property and phase transformation in a commercial dental casting high gold alloy was investigated as a function of ageing temperature and time usingmicrovickers hardness tester, X-ray diffraction, optical and electron microscopy andEPMA analyser. 1. With increasing ageing time, the hardness of solution-treated gold alloys increasedslowly at the initial stage of ageing treatment at an ageing temperature of 300~400℃,and it reached a maximum value of hardness at the medium stage. Finally, it decreasedgradually during further ageing. The maximum value of hardness at was similar with thatof the conventional materials and suitable for using as the crown & bridge. 2. During isothermal ageing at a temperature range of 300~400℃, three phasesconsisting of the Au-rich α₁phase with a face-centered cubic structure, the Pt3Zn α₂phasewith an ordered AuCu3(L12) type(f.c.c.) and the Pt-rich α₃phase with face-centered cubicstructure in solution-treated gold alloys were transformed into different three phasesconsisting of the α₁phase, the α₃phase and the PtZn βphase with an ordered AuCu I(L10)type. 3. The hardening of gold alloys was attributed to the lattice strains of the matrixresulting from the transformation of the α₂phase to the βphase.4. The softening of gold alloys during over-ageing was attributed to the coarsening ofthe nodules consisting of the βphase and α₁matrix.

Three t-amines, 4-(dimethylamino)benzoic acid (ABA), 4-(dimethylamino)benzaldehyde(MBA), 4-(dimethylamino)benzophenone (MBP), were investigated as new visible lightphotoinitiators for a dental resin composite of UDMA in order to improve photopolymerizationeffect. Three t-amines mixed with three photosensiizers, CQ, PD and DA, respectively. And thephotopolymerization effect of photoinitiators were compared with that of 4-(dimethylamino)ethyl methacrylate (AEM), the most widely used photoinitiator. Thephotopolymerization efficiency of UDMA containing the photoinitiator increased withirradiation time. The increase was in the order: MBP<ABA<AEM<MBA. And thephotopolymerization efficiency of CQ containing MBA was better than PD or DA.

The movement range on the semi adjustable articulator and the movement range in anoral were measured. And then I studied to analyze the gap. I got wax records by themovement on the semi adjustable articulator, the movement in an oral. I measured thedistance of the cusp tips that are close to the mesial direction and the distal direction, thebuccal direction and the lingual direction then I compared gaps.As I saw results on data, I knew that the semi adjustable articulator represented therange of mandibular movement restrictively. I could find the decisive contradiction thatthe sliding movement finished on the semi adjustable articulator although it did not finishin an oral. When the sliding movement does not reappear exactly, it brings a fatal failureto the dental prosthesis. In addition it is impossible that the semi adjustable articulatorrestores the movement in an oral because the lateral condyle inclination and thehorizontal condyle inclination are appeared to be straight. Therefore dental prosthesisseswere made by the semi adjustable articulator, they will interfere with a mastication.I have obtained the following results;1. The distance of sliding movement on the semi adjustable articulator showed shorter than the distance of sliding movement in oral. This means the increase of cusp inclinationof the dental prosthesis that was made on the semi adjustable articulator. Therefore,when the lateral movement occurs in oral, there is a possibility to become the prematureas the increase of cusp inclination. 2. The difference in the range of movement is considered as the gap that is madebecause the movement only can be occurred as straight in the semi adjustable articulator.3. When the dental technician understand mandibular movement and articulatordeficiencies, they can attain proficiency in use of the articulator and reduce the gap.

Titanium alloys have been used for dental materials due to it`s very good biocompatibility.Ti-6Al-4V alloy instead of pure titanium is being widely used as biomaterials has somecharacteristics such as high fatigue strength, tensile strength and corrosion resistance.But it has been reported recently that the vanadium element expresses cytotoxicity andcarcinogenicity and the aluminium element is related with dementia of Alzheimer typeand neurotoxicity.The Ti-Nb alloys has designed and examined corrosion resistance. Ti-3wt.%Nb(αtype),Ti-20wt.%Nb(α+βtype) and Ti-40wt.%Nb(βtype) alloys were melted by vacuum arc furnace.The corrosion resistance of Ti alloys was evaluated by potentiodynamic polarization test inthe solution of 0.9% NaCl and 5% HCl. The results can be summarized as follows:1) For the corrosion test in the solution of 0.9% NaCl and 5% HCl, the corrosion behaviourof Ti-Nb alloys was similar to ASTM grade 2 CP Ti.2) The corrosion resistance of Ti-20Nb alloy was better than that of CP-Ti, Ti-3Nb, Ti-40Nb alloy in 0.9% NaCl and 5% HCl, solutions.

This research has been attempt to examine closely factors that high cost and value tooverall satisfaction state for dental implant prosthesis, re-utilization intention, inducementintention of the general hospital dental service user and provide basis data necessary toestablish competitive general hospital dentistry management strategy.Collected data using own recording way questionnaire from April 17, 2004 to May 15, 2004choosing 142 people that agree on this research and question of 361 people that dentalimplant prosthetic treatment finished from March 1, 1999 to March 1, 2004 for this.Major analyzation consequences are as follows :First, general satisfaction, re-utilization intention, inducement intention for implantprosthesis that highly correlation variables are kindness, explanation, medical treatment leveland appreciation of the aesthetic.Second, correlation is high relatively between re-utilization intention, inducement intentionin the 3 variables such as general satisfaction re-utilization intention, inducement intention.Third, the result of multiple regression analysis showed that most significant effectivefactors are satisfaction with explanation of dental implant prosthesis between the 3 dependant variables such as general satisfaction, re-utilization intention, inducementintention. In looking into these consequence, how to improve that raise satisfaction about dentalimplant prosthetic treatment and to establish patient focused care service system for dentalimplant prosthesis ,it is consider that explain enough about implant prosthesis and raisequality of medical examination and treatment level, including satisfied with fabrication ofgood esthetic dental implant prosthesis.

he purpose of this study is to understand the present conditions and problems of the jointeducation between industry and the academic world in the field of dental technology whichwere identified by the department of dental technology with the related industries and tomeet their expectations for the cooperative education. The results of this study will be able tobe furnished as basic data in deciding the direction of policy toward skillful dental technicianswith a view to improving job employment rate of college graduates. The questionnaires fordata were done by the dental technicians working in Daegu City and Kyeongbuk Province andstudents studying at the department of dental technology, Daegu Health College. Thequestionnaires of this study were processed by SPSS program.We could confirm through the investigation that on-the-job training as one of the jointpolicies between industry and the academic world is closely related to all the college educationand that the results of on-the-job training can be expected under the close cooperation andthe complementary relationship between industry and the academic world. Therefore, this study indicates the directions of policy toward skillful technicians through the cooperationbetween industry and the academic world as follows :1. The cooperative systems among industry, academic world, and government are neededfor the improvement of efficient job employment rate. The continuous training programs areneeded to be built up for the maintenance and development of the technicians’specialty afteremployment.2. The all-in-one educational programs both education and employment are needed for theon-the-job training through the cooperation between industry and the academic world, andthe activation of the organizations which fully operate them is also needed. That’s because thesufficient on-the-job training as one of the joint policies between industry and the academicworld and the education of the whole man and the improvement of sociality for the expectantgraduates in the academic world can be the methods which reduce the jobless rate and thejob-change rate.

In this study, we investigated the growth rate on the basis of the sex and the yearamong the subjects of the licensed dental technicians from the year 1970 to 2003 inKorea. In line with this investigation, this study aims to provide a basic material withregard to the state of dental technician workforce by sex and to suggest a need toreassignment of workforce by sex in accordance with the specific job description. Theresults of the study are as follows; First, among the licensed dental technicians from 1970to 2003, males came to 11,589 and females, 5,976, which shows the number of males are1.9 times higher than that of females. To put the mean sexual composite from 1970 to2003, male was 82.9% and female 17.1%, indicating the number of males are 4.8 higherthan that of females. Second, Of the mean increasing rate until the year 2003 in contrastto 1970, male was about 351 and female was about 181, which shows the number of malesincreased 1.94 times higher than the females. Comparing to the mean increasing rate ofthe last year, female came to 25.56% and male 10.73%, which reveals that the femaleswere about 2.4 times higher than the males. In the case of the growth rate, females increased by 1,196,20 times and the males, 26,41. As a result the growth of females areabout 45.3 times higher than the males. Third, in the case of the growth rate from 1980 to2003, females came to 47.85 times and males 9.16, which shows the growth rate of thefemales was about 5.2 times higher than the males. In contrast to the year 1987, thegrowth rate until 2003 shows that the females came to 5,13 times and the males 2.70,which indicates the growth rate of females was about 1.9 times higher than males.Fourth, Compared to the year 1990, the growth rate until 2003 shows that females cameto 3.40 times and males 2.03 indicating the growth rate of the females was about 1.7times higher than males. In contrast to the year 2000, the growth rate till 2003 showsthat females was 1,34 times and males 1.15 times increased. Fifth, the ratio of sex by theyear among the licensed dental technicians is as follows; ratio of male to female in 1970was 91.2 to 1. In 2003 the ratio came to 2.0 to 1. The number of growth by sex in 1970came to 24.0 males to 1 female. But the figure was equalled in 2003.

Collecting materials for study on teaching efficiency and satisfaction of clinical training, itchanges. Dental technology’s educational procedure to many ways of a prospect. In acircumstance that needed higher level of education, this study is aimed on realizing animportance of clinical training through the various materials that previously carried out andoffering basic knowledge to take better clinical training for the students.Study results below1. This Investigation conducted on 123 of sophomores(70.3%) and 52 of juniors(29.7%) whohave been taken clinical training, and men’s proportion(51.45%)is a bit higher thangirls(48.6%). The 64% of respondents taken largest proportion were 20 to 24 years old. As67.9% of respondents attended daytime school and 30.3% of them attended nighttime one,their school time shows a little difference. In a question about relation ship, one answered“Harmonious”took largest proportion by 72.6% during training, and about the degree ofsatisfaction of campus life who answered “normal”were the most with 59.4%.2. About the reason choosing dental technology as a major, 41.1% taken the most answered“due to the specialized job”, “Getting job easily”was second with 26.9%, and third was “recommended from around”with 18.3%. 50.3% of the respondents answered “normal”aboutthe Satisfaction of their major, student marked in grade “B”most with 51.4% 3. In a investigation result about clinical training statues and preference, most(72.6%)choose place less than 10 for clinical training, and 60.6% of them resided own home. About their commuting time from home to training place, 44% was under 30min, 40% tooktime 30-60min. It shows students prefer shotter distance in terms of choosing training place.4. Each part manager took large proportion as a clinical trainer with 33.7%, Trainingcurriculum reform and developing method were most answer as a improvement measure aftercompleting training with 30%.5. The average of total score about clinical training was 3.15 of 5. In the detailed question,‘satisfaction of clinical training’got 3.38 as a highest score, the lowest score was 2.86 that isabout satisfaction of clinical training period. The average score about efficiency of study was2.86 and in detailed question, ‘a Role model’got 3.26 as a highest score and participation ofstudent got 3.05 as a lowest score. 6. The result of T-test to see the difference of the satisfaction according to the generalcharacter and clinic training condition between teaching efficiency is that the degree ofsatisfaction of clinical training showed statistical significance only in the degree ofsatisfaction of campus life(p<0.05), and teaching efficiency has a statistical significance withtheir age, grade, and satisfaction of campus life (p<0.05).7. The relation between of teaching efficiency of clinical training and satisfaction of clinicaltraining of dental technologic student has a statistical meaning in significance leveler 0.01. Now, therefore we suggest following based on these result. 1. To elevate satisfaction of clinical training, it agentry needs development of consistentclinical training curriculum.2. To grasp the satisfaction and requirement, in needs to measure anxiousness andsatisfactory degree after completing training3. To train efficiently and evaluate efficiency over the teaching activities, it needs todevelop measuring tools for teaching efficiency in terms of teacher’s important rules in aclinical training. 4. Strengthen the relations with the study developing and managing curriculum gatheringtheoretical knowledge and practice. And make an effort to apply to their students.5. Let the trainee take a class setting a belief, sense of value, function and obtain behaviorby making the students comfort over clinical training as increasing teaching efficiency.

Objectives;The purpose of the present study is to investigate workplace satisfactionlevel of dental technicians and the differences between that of dental lab owner’s and thatof employed dental technicians, who are working in dental laboratories. Methods;Samples were comprised of 137 dental technicians working in dentallaboratories. Data were collected through self-administered questionnaires and analyzedto frequency distribution, correlation, t-test and multiple regression analysis. Results; 1) Dental technicians generally are ‘somewhat or a bit satisfied’with their workplacesituations, regardless of position, sex, and individual career. 2) Mean values of 4 items out of 11 work situation factors of employed dentaltechnicians were significantly lower than those of lab owner’s. The 4 items are theopenness of management, working environment, pay, and policy in promotion and raise.They would be sources of dissatisfaction and conflict. 3) Level of satisfaction was significantly correlated with 2 subordinate variables, i.e.working conditions and administration policy. There is a tendency that administrationpolicy is a bit more important for lab owners, while working conditions are a bit moreimportant for employed dental technicians. Conclusion;The employer-employee relationship of dental technicians seems to besound, as no signs of troublesome problem is detected. But the discrepancy revealed in theabove results is telling that there certainly exist some disagreement in the viewpoints ofthe two groups. It is necessary for the dental technicians to find ways to deal with thepossible triggers of discord and discontent.

The purpose of this study was to evaluate smoking of dental technicians in 2005, and wehave distributed questionnaires about smoking in 2005-KDTA general meeting and analyzedthem. All 555 respondents who attended KDTA general meeting were selected by randomsampling. However we dismissed 41 because of invalidness, so we got 504 people. Therefore,we have got conclusions below:1. The rate of smokers who attended in 2005 KDTA was 33.93%, 46.3% in men, 1.44% inwomen. When we compared to other specialist groups, the rate of dental technician smokerswas higher than them.2. When we analyzed the ages of first smoking, 55.56% of the people started to smoke whenthey were in 24 years old. This result was very similar to the rate of dentist smokers in 2005KDA research.3. According to the answers of smokers and people who wire smokers in the past aboutquitting smoking period and willness in future, 60.82% among all members failed to quitsmoking and also 69.2% among all members did not leap over 3 months but, they have thought to quit smoking for 6 months. 4. According to the answers about antismoking training related to environment in dentaland clinical labs, most dental technicians(92.66%) have never been trained, also 37.70% amongall members have not fulfilled their duty at self office. They have not recognized the danger ofthe indirect smoking. 5. When we asked chiefs in dental and clinical labs, the reason why they, didn't do theantismoking training their staffs, 32.1% of them replied that they were so busy, and 42.13%did because of their staffs, abhorrence and needlessness.6. As Pan-dentistry members, over 80% agreed to the thought of the antismoking, also hadmedical knowledge about smoking. So we have the conclusion that dental technicians haveidentification as the Pan-dentistry members.7. Most dental technicians expected KDTA to play a role about the antismoking training fortheir members.We have two suggestions to KDTA about the antismoking problem for members accordingto above conclusions.First, KDTA should prepare the antismoking training in the curriculum. Second, KDTAshould support the antismoking programs of schools for students.

This study purposed to offer basic data for safety education of the dental laboratorytechnology after the investigation of how much the students in the dept. of dentallaboratory technology are aware of the danger of each instrument, equipment orlaboratory procedure that they use during laboratory and how much they demand safetyeducation for this. The objects for this study were 423 students who were in the dept. of dental laboratorytechnology. In this regard, four colleges which have the dept. of dental laboratorytechnology were randomly selected to do a questionnaire survey. SPSS 12.0 was used toanalyze the collected data. The results were as follows: As for satisfaction with their major, the respondents answered Satisfied (59.1%),Average (35.5%) and Dissatisfied (5.4%). In terms of the production process of a partialdenture, they considered casting, polishing the casting body, polishing denture and burnout were most dangerous in order. As for the production process of a full denture, whatthey regarded as the most dangerous in order was polishing denture, deflasking and waxwash. Regarding the laboratory procedures of porcelain material, casting, trimming castingbody, polishing porcelain material and burn out were the most dangerous procedures thatthey perceived. With regard to materials for use, alcohol, polishing, metal and wire werethe most dangerous ones they thought. As for the handling characteristics of eachmaterial, small towns showed a higher demand for safety of the handling characteristicsof alcohol. In terms of school year and sex, juniors and girls had higher scores in thedemand for safety of the handling characteristics of acid. Regarding the handling characteristics of each equipment and instrument, all of smalltowns, juniors and girls showed the highest demand for safety of the handlingcharacteristics of alcohol lamps. With regard to scores in the demand for safety of othercharacteristics, all of small towns, juniors and girls had the highest demand for safety ofemergency treatment. Concerning the demand for safety education by the completion ofsafety education, in terms of each material, highest was the demand for safety of acidfrom the group which completed safety education. In regard to equipments andinstruments, when it came to the demand for safety of the handling characteristics ofcasting machine, the educated group’s demand for safety of acid was higher. Regardingother characteristics, the group which was not educated gained higher scores in thedemand for safety of emergency treatment. 11. In all areas(materials, machines and others), small towns, girls and juniors showedhigher scores in the demand for safety. Based on the above results, it was found that when students conduct the laboratory ofdental technology, they would think that many materials, instruments or equipments foruse are very dangerous. However, safety education was not fully given to them.Regarding the scores in the damned for safety education, the highest was 4.16 and thelowest was 3.43, which suggests that the scores were generally very high. In this regard,it is necessary to continue delivering a systematic safety education of materials,equipments or instruments used during the laboratory of dental technology. Therefore, through the analysis of each material, instruments or facility used in everylaboratory and each process, safety accident types and accident risk factors should beinvestigated to develop educational materials for this. Moreover, it is required to opensafety education as a single course of study or insert safety contents of all materials andmachines into the class of dental laboratory instrument or dental materials for thepurpose of a systematic and thorough safety education to prevent a safety accident duringlaboratory.