Earticle

The aim of this study is to propose effective measures for shortage of manpower of dental technologylaboratory in Gangwon province by means of examining not only the history of Gangwon association,present condition of transference of members of Gangwon association from 1990, of missing members andannual rate of participation in repair education with setting object of study into Gangwon association underthe influence of the Korean Dental Technology Association but also the present condition of opening andclosing laboratory, amount of business connection and condition of shortage of manpower and its field withsetting object of study into 28 dental technology laboratories.Results from this study are like followings : First, Gagnwon association was established in 1984 as the eleventh in the line of the board,reorganization of board is conducted 8 times up to the eighth in the line of the board in 2001. board iscomposed of 16 persons including president and operated its term as 3 years.Second, a number of representative and ordinary member of Gangwon association has increasedgradually from 1992 to 2001. in aspect of annual rate of participation in repair education, representative's ismore higher than ordinary member's overall. the worst rate of whole members' is shown as 47.9% and theits best rate is shown as 92.0%. in addition, 70~80% rate of participation into repair education is shownmost frequently as 8 times of whole 20 times from 1992 to 2001. hird, 29 authorized dental technology laboratories have registered in Gangwon association until march2002 within 9 cities and counties. in consideration of establishment location. Gangneung city has mostamount as 7 laboratories(24.1%), Wonju city has 5(17.2%), Samcheok city and Sokcho city, each has4(13.8%), Chuncheon city has 3(10.3%), Donghae city and Taeback city, each has 2(6.9%) and Yangyangand Yongwol county, each has 1(3.4%)Fourth, amount of work personnel of laboratory in Gangwon province is 1~10 persons as the maximumvalue. 23 laboratories(82.1%) have their own work personnel as amount of 5 and below. in aspect of mainbusiness, most of laboratories focus on the Porcelain and Crown. and 16 laboratories(57.1%) have theirown expensive equipments such as Milling. its also suggests that 16 laboratories(57.1%) suffer theirshortage of working personnel. specifically, 6 laboratories(21.4%) suffer the highest shortage especially inDenture field, Fifth, whole number of Gangwon association is up to 101 members (28 representatives and 73 ordinarymembers) until December 31th 2001. amount of immune from repair education of Gangwon associationuntil October 2001 is up to 10 persons, and missing members from 1997 is up to 18 persons, suspension ofbusiness is up to 4 persons. in aspect of transference from 1990, transfer-in is up to 21 persons and transfer-out is up to 16 persons.

The purpose of this study was to examine the respiratory system health condition of dental technicians and tobe of use for more successful health management and health promotion for them. The subjects in this study were155 dental technicians who were working in North Jeolla province. Out of them, 70 dental mechanics wereinvestigated in 1993, and 85 were surveyed in 2001. And the reports of the two groups on respiratory distress,including cough, sputum, phlegm, the notable sound of breathing, nasal discharge, coryza, shortness of breath andgasping, were compared. The findings of this study were as below:1. The cough report rate was 24.3% in 1993 and 16.5% in 2001. There appeared approximately 7.8% decreasebetween the two years. The most powerful variables included working hours and age.2. The complaint rate of sputum and phlegm was 47.1% in 1993 and 43.5% in 2001. The rate of 2001 reducedby 3.6%. Whether or not they smoked was identified as the most influential variable.3. The report rate of shortness of breath and gasping was 7.4% in 1993 and 12.9% in 2001, and this rateshowed about 1.5% increase in the latter year. The biggest variables were working hours and career.4. The complaint rate of nasal discharge and coryza was 41.4% in 1993 and 44.7% in 2001, which showedabout 3.3% increase. The largest variables were smoking and career.5. The report rate of the notable sound of breathing and breathing in light little gasps was 12.0% in 1993 and17.6% in 2001. There was approximately 5.6% increase, and the most powerful variables were working hours andcareer.

In dental prosthetics, the application of metal-ceramic restorations has steadily increased since theirintroduction. This is due to excellent esthetics in combination with high mechanical stability. In order to optimumbond strength between metal and ceramics, controlled oxidation of metal substructure is essential factor. Beryllium containing and beryllium free Ni-Cr alloys for metal-ceramic restorations were evaluated forthe metal-ceramic bond strength by changing heat treatment for oxide formation. A mechanical three-pointbending test was employed to evaluate the interfacial bond strength of metal-ceramic. In each metal, platetype specimens were used for mechanical three-point bending test .With Ni-Cr alloys for metal ceramics, mechanical three-point bending test showed that double degassingwas more available preheat treament method than another. It was found that beryllium containing Ni-Cralloys are more effective than beryllium-free for metal-ceramic bond strength.

To develop the natural antibacterial agents which don't have any toxicity against man, collected several speciesof medicinal plants were tested for their antibacterial activity from dental caries bacteria Streptococcus sanguis.The result of using paper disc method and the result of viable cell counting method, Phellodendri Cortex wasselected as antibacterial agent. The high antibacterial activity was acquired at high extraction temperature and longextraction temperature. The antibacterial of Phellodendri Cortex was not effected by the concentration of ethanol.

The purpose of this study was to be of use for getting rid of job stress from dental technicians, byexamining how much they were stressed out at work place as one of the professional medical personnels.The subjects in this study were 255 selected dental technicians who were working in the region ofTaegu. The one-on-one interview was conducted from March 1 to 30, 2001, with structured questionnaire.The questionnaire sued in this study included 19 question items about the general characteristics and 29items regarding job stress. The job stress was categorized into seven subareas based on earlier studies andconsidering the job situations of dental technicians: heavy workload, job conflicts, improper treatment, roleand job knowledge, human relations, physical environment and personal matters. The job stress extent wasmeasured on five-point Likert scale that is widely used in social science: one point for no stress, two forlittle stress, three for so-so, four for a little stress, and five for severe stress. Therefore, a higher point meansa severer job stress. The reliability of the questionnaire turned out very good with Cronbach a = 0.9272.The findings of this study were as follows:1. The general characteristics of the dental technicians investigated could be described as below:(1) By gender, 80.4% of the dental technicians were male, and 50.2%, the largest percentage, were intheir 20s, followed by those in their 30s, those in their 40s, and those in their 50s in the order named. (2) The most common work place was dental technician shop(92.5%), followed by dental technologyroom in dental hospital or clinic and in general hospital in the order named. The primary duties werecoating materials work(30.6%), followed by sculpture, grinding, partial and full denture and orthodontics inthe order named. 2. The most larges(1) The most largest motivation to be a dental technician was its being a professional(33.7%), followedby the advice from others, their own aptitude, and good economic treatment in the order named. 3. Their job stress could be explained as below:(1) Their collective job stress average was 3.96°æ0.50 on the basis of 5 point, which showed that theywere exposed to a fairly severe job stress.(2) By area, they were most stressed out from heavy workload (4.12), and they also were severelystressed from role and job knowledge(4.02) and personal matters(4.00). (3) By situation, they were most stressed when the disagreement of prosthesis that results from aspecific error is unconditionally attributed to them(4.43). And they were also stressed a lot when theirworkload increases due to the rework(4.38), when a dentist asks something difficult for them toresolve(4.20), when heavy workload makes their working hours irregular and it's impossible to lead apersonal life or have leisure time(4.16), and when they are o work for an excessively short time(4.16). Thisfact indicated that most of the dental technicians were exposed to a lot of stress in conjunction with jobperformance. 4. The main duties they took charge of didn't make any significant difference to their job stress, butyielded a significant difference to the extent of job stress in individual areas and the order of the moststressful one. Those who were engaged in grinding were most stressed from their own matters, whereasheavy workload was most stressful for those who were engaged in the other types of works. 5. As a result of seeing if their personal characteristics yielded any differences to job stress, the personalcharacteristics that made their job stress vary significantly were working hours, motivation of being adental technician, job satisfaction and willingness to continue doing dental technology works. There was atendency that longer working hours led to severer job stress, and those who chose to be a dental technicianaccording to their own aptitude were less stressed than the others who became a dental technician becauseof economic reason or advices from others. And the people who were satisfied with their job were exposedto less job stress than the others who weren't, and those who had an intention to keep that job as much aspossible were less stressed, compared to the others who hadn't.

This study was performed to observe the microhardness change of the surface and the bonding strengthbetween the porcelain and alloy specimens in order to investigate the effects of appended indium, tin and copperon interfacial properties of Au-Pd-Ag alloys. The hardness of castings was measured with a micro-Vicker'shardness tester.The interfacial shear bonding strength between alloy specimen and fused porcelain was measured with amechanical testing system(MTS 858.20).The microhardness of Au-Pd-Ag alloy was increased by adding indium and tin, but not increased by addingcopper. The shear bonding strength of Au-Pd-Ag-Sn alloy and Au-Pd-Ag-Cu alloy showed 87MPa, 57MPa. Thehigher concentration of adding elements showed the higher shear bonding strength.

Accurate acquisition of surface geometries such as machined surfaces, biological surfaces, and deformed partshave been very important technique in scientific study and engineering, expecially for system design,manufacturing and inspection. Two camera method is relatively simple with an acceptable accuracy. In this paper,a new method is studied to acquire 3D geometric data of the small object such as a die in stone model. When thedevices, cameras, laser beam and object are in a perfect plane, the calculation becomes very simple with less error.But this paper shows that arbitrarily positioned system can also be used to obtain 3D data.

This study was performed to evaluate the importance of parents, knowledge, cognition and behaviour aboutdental health care on the development of dental caries in preschoolers.Subjects were comprised of 170 preschoolers collected from three preschoolers placed in Pusan and Kimhaearea and study period were 6 months from January, 2000.Examination on the preschoolers' dental health and questionnarie survey on parents' knowledge, cognition andbehaviour about dental health care were conducted. Collected data were analyzed by chi-square test and t-testusing SAS program.Dental caries was so prevalent as the rate of 73.5%. And, the rate was different by the area(p=0.001), andincreased with preschooler's age(=0.004). The parents gain the knowledge about dental health care mainly fromdentist or dental hygienist(32.9%), newspaper, magazine booklets(26.5%), TV and VTR tape(20.0%), etc, butrarely from school health education(4.7%). Caries prevalence was significantly lower in case of regular brushingthan that of insufficient brushing(p=0.002) and in case of consistently informing brushing time to theirchildren(p=0.014).This results showed that the dental health care for preschoolers is insufficient and the most important factor forcaries prevention is regular brushing. And it seemed that the parent's concern and knowledge play an importantrole for the prevention of preschooler's dental caries. Dental health education would be focused on the parents,especially for the practice of preventive behavior by preschoolers themselves.

For biomedical applications, Ti-X%Zr-Y%Nb-0.2%Pd(X:10~20, Y:2~8) alloys not containing harmful Al andV were newly designed, and the effect of alloy composition and heat treatment on the microstructure andmechanical properties was investigated. From the results, it was shown that the mechanical properties wereenhanced with the addition of Zr or Nb. The effect of heat treating on room temperature strength was investigatedby aging treatment after solution treatment. The mechanical properties of Ti-20%Zr-4%Nb-0.2%Pd alloy aged at400for 10hrs was found to be superior to those of the pure Ti and Ti-6%Al-4%V ELI alloy.

The first function of occlusion is mastication. Therefore the functional restoration of occlusal surface is veryimportant. The restoration of occlusal surface is three method as wax bite technique, F.G.P. technique, conetechnique. Many dental technician is using compound method. I am using compound method of wax bitetechnique and cone technique. I have knew common point on each teeth during I have waxing up wax pattern. SoI studied on the design waxup technique for mandible molar occlusion. The results of the study were as follows;1. The dam wax up method can restore axial contour of teeth very easy and make short working time of wax pattern2. The height of dam must be same with cusp of adjacent teeth.3. Automatically the contour of tooth is appeared if the contour of dam is relationship with cuspid line ofadjacent teeth.4. The height of contour of buccal, lingual surface is formed natural curve to add fluid wax by gravitation.5. The development groove of mandible first premolar is appeared V form.6. The development groove of mandible second premolar is appeared Y form.7, The development groove of mandible first molar is appeared M form.8, The development groove of mandible second molar is W form.9. The embrasure is formed to carve around contact point area as round convex. It affects to axial form of tooth.10. The buccal, lingual groove of molar is formed parallel with direction of teeth arrangement.

There are some cases that dental prosthesis does not operate as properly as expected in oral mouth. The reasonsare such as a distortion of the mandibular, a fault of impression taking system or an extrusion of remaining teeth.One of dental prostheses to consider in the situations is the attachment which connects segment bridge. Active discussions are managed on theoretical side of this field but few on clinical side of it, which must beconsidered first. Accordingly I'd like to suggest a theoretical background for connect attachment of fixedsegmented bridge.1. As a bridge gets longer, burden on dental ligament is increased and the hardness of a bridge is lessened.2. The flexibility of a bridge increases in ratio to 3 multiplication of the length and decreases in ratio to 3multiplication of the width of occlusal surface and base of pontic.3. Precision rest is needed to cope with the shake of teeth and the difference of axis direction among abutments.4. Female part of the precision rest should be on middle abutment distal and male one on mesial of pontic. 5. Segmented attachment can be efficiently used to cope with long span bridgework and also in case that onepiece casting can't be done because of slant of abutment.