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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Acedemy of Dental Technology
Journal Basic Information
Journal DOI :
Korean Academy of Dental Technology
Editor in Chief :
Volume & Issues
Volume 29, Issue 2 - Dec 2007
Volume 29, Issue 1 - Jul 2007
Selecting the target year
Factors of Skin Diseases in Dental Technician (Focus in Seoul)
Ahn, Jae-Seok ; Kim, Hae-Joon ; Oh, Sae-Yoon ; Kim, Woong-Chul ; Kim, Ji-Hwan ;
Journal of Korean Acedemy of Dental Technology, volume 29, issue 1, 2007, Pages 9~21
This study was conducted to determine the cause and prevalence of occupational skin disease in dental technicians working in Seoul, Korea. and to investigate the relation between these work condition and skin disease of the hand, wrist and forearm. This study was based on the Nordic occupational skin questionnaire(NOSQ), a self-administrated questionnaire which was modified to investigate the dental technician's occupational factors in domestic circumstances. The number was distributed to 500 dental technicians who participated in annual continuing education for dental technicians of the Seoul metropolitan area in April 2006. Of the subjects, 62(30.4%) had eczema and 70(32.9%) had urticaria, as diagnosed. Of the subjects with the symptoms of urticaria, 30 complained of atopic dermatitis, 65 complained of allergic rhinitis, 56 complained of allergic conjunctivitis, and 18 complained of asthma. The group with atopic history had a higher frequency of eczema or urticaria than the group without atopic history. From multiple regression analysis, the group who had a history of atopic dermatitis also had high symptom rates of eczema. The group who had a history of allergic rhinitis and allergic conjunctivitis had high symptom rates of urticaria. The urticaria symptom rates were higher in those wearing gloves than those who did not for the type of work.
Effect of MgO addition in glass composition on the strength of zirconia-glass composites
Lee, Kyu-Sun ; Lee, Chang-Wan ; Lee, Chae-Hyun ;
Journal of Korean Acedemy of Dental Technology, volume 29, issue 1, 2007, Pages 23~34
The quantity of MgO in the Zirconia of 20wt% Frit has been varied and the sintering temperature has been differentiated to monitor the changes in the mechanical features. The rise of sintering temperature from 1100
was followed by higher sintering density. And, at a sintering temperature, the increase of the quantity of MgO was followed by lower sintering density. The bending strength has been lowered as the quantity of MgO increases in the Zirconia of 20wt% Frit, which seems to be because the MgO functions as impurities degrading the mechanical features. In terms of micro-structure analysis, the pore has been greatly enlarged, while the density varied very little, when the MgO of 3wt% was added. The size of pore became smaller as the added quantity of MgO increased larger in the sequence of 5wt% and 7wt%. But, the pore-generating rate became higher as the added quantity of MgO increased in the sequence of 3wt%, 5wt% and 7wt%. Thus, it is possible to summarize that the small quantity of MgO, say, of 3wt%, promotes the grain growth, and the large quantity of MgO, say, of 7wt%, hinders the grain growth. Also, if the quantity of MgO exceeds some level, the MgO hinders substances from moving, which, ultimately, keeps blowholes from becoming enlarged or extinct, and makes pores small and dispersed in broad area. In conclusion, the study on the change in the size of pore shows that the larger the quantity of MgO is, the more the micro pores are, thereby degrading the mechanical features.
Shade Matching Identification of in Vivo Natural Teeth and Porcelain-Fused-to-Metal Crowns
Cho, Hong-Kyu ;
Journal of Korean Acedemy of Dental Technology, volume 29, issue 1, 2007, Pages 35~48
The purpose of this study was to evaluate shade selection using conventional visual assessment in vivo natural teeth and porcelain-fused-to-metal (PFM) crown. Maxillary central incisors, lateral incisors and canines of one hundred twenty four college women were used as vivo natural teeth. Fifty one PFM crown for maxillary central incisor fabricated by dental laboratory were used as experimental materials. Using Vitapan Classical Shade Guides, shade selection of natural teeth was measured by each college woman and shade selection of PFM crown was measured by three ceramists with more than ten years career. Both natural teeth and PFM crown shade selection were measured through Shade Eye-Ex. From the shade selection comparing, following results were obtained. The results were as follows: 1. The shade matching identification of natural teeth between the shade selection using Vitapan Classical Shade Guides and the shade selection using Shade Eye-Ex was 27.4% in maxillary central incisor, 13.7% in lateral incisor and 18.5% in canine. 2. Among the shade selection of PFM crown by three ceramists, the shade evaluation of three ceramists were same only in ten cases. In twenty case, those of two ceramists were same. 3. The shade matching identification of PFM crown between the shade selection using Vitapan Classical Shade Guides and the shade selection using Shade Eye-Ex was 38.6% in average. These results suggest that the shade selection using conventional visual assessment should be dealt with care in clinic and need a credible method for shade matching color.
A Study on the Mechanical Properties Based on Frit Addition in 3Y-TZP Zirconia Composition
Kwon, Eun-Ja ; Lee, Gyu-Sun ; Lee, Chae-Hyun ;
Journal of Korean Acedemy of Dental Technology, volume 29, issue 1, 2007, Pages 49~57
This study was to add crushed frit with different grain sizes to 3Y-TZP so that it could determine the mechanical properties depending on sintering temperature. In this study, 3 types specimens were prepared in powder with respective additions of 20wt.% frit, which was sized through 24-, 48- and 72-hour ball milling with zirconia. Then, sintered pellets were tested in experiments under the temperature variations for different compositions. As a result, this study came to the following findings: 1. It was found that the higher sintering temperature and the longer ball milling time of frit led to the higher sintered density. 2. Bending strength tended to increase with higher sintering temperature and longer ball milling time of frit. 3. Hardness tended to increase with higher sintering temperature and longer ball milling time of frit. 4. However, it was found that fracture toughness didn't vary significantly depending on sintering temperature. From these findings, it was concluded that the smaller frit grain size and the narrower particle size distribution of frit lead to the better mechanical properties.
A Study on Correlation of Teaching Efficiency and Satisfaction of Clinical Practice of Dental Technology Students (in Seoul and Kyung-ki)
Sung, Hwan-Kyung ; Lee, Kyu-Sun ; Hwang, Jae-Sun ;
Journal of Korean Acedemy of Dental Technology, volume 29, issue 1, 2007, Pages 59~72
This study executed to offer the basis for dental technology student who chanced better clinical training. This investigation conducted on 267 of seniors who have been taken clinical training to self written a questionnaire. We used and dealt a spss 12.0 program. Study results below 1. In a question about relationship, one answered "Harmonious" took largest proportion by 40.9% during training, and about the degree of satisfaction of campus life who answered :normal: were the most with 50.0% 2. In a question about clinical training place, most(50.0%) choose place less than 10 for clinical training, and more than 10 for clinical training with 29.7%. Residue statues was most of them resided own home with 78.6%. About their commuting time from home to training place, 50.0% was under 30min, 34.1% took time 30
60min. 3. In a question about clinical trainer, most (34.4%) choose as dental lab president, as each part manager with 34.1%, a senior with 7.6% and not exist to clinical trainer with 7.6%. 4. A perfect score about teaching efficiency and satisfaction of clinical practice of dental technology students was 5. The average of score about satisfaction of clinical practice was 3.25 and circumstance of clinical training got 3.50 as a highest score. the lowest score was 2.87 that is about satisfaction of clinical training period. The average of score of teaching efficiency was 3.25. 'a Role model' got 3.55 as the highest score and 'utility for student' got 3.12 as the lowest 3.12. 5. The result of T-test to see of the satisfaction according to the general character and clinic training condition between teaching efficiency is that the degree of satisfaction of clinical training showed statistical significance only in the degree of satisfaction of college life(p<0.05), teaching efficiency has a statistical significance with age and satisfaction of college life(p<0.05). 6. The relation between of teaching efficiency of clinical training and satisfaction of clinical training of dental technologic student has a statistical relation r=0.551 and a statistical meaning in significance leveler 0.01.
An Empirical Study on Dental Technicians' Job Satisfaction
Nah, Jung-Sook ; Yoo, Nak-Kuen ; Suh, Euy-Hoon ;
Journal of Korean Acedemy of Dental Technology, volume 29, issue 1, 2007, Pages 73~91
The purpose of this study is to investigate relations among job-related attributes of dental technicians. Findings of the study can be summarized as follows. Differences in four job-related attributes among dental technicians in accordance with their titles were investigated to find that dental lab managers were higher in job satisfaction than chief and assistant technicians of the lab. Dental lab managers were given the best work climate, followed by chief technicians of hospital, those of dental lab and assistant technicians. Job competence was highest in part of the managers, followed by chief assistants of hospital, those of dental lab and assistant technicians. But work facilities that were being used by dental technicians were not significantly different in quality in accordance with their titles. Assistant technicians were lower in job satisfaction, given work climate and job competence than managers and chief technicians of both hospital and dental lab. Under same work conditions, female dental technicians were higher in job satisfaction than male ones. Dental technicians' job satisfaction were most affected by work climate, followed by job competence and the quality of work facilities in order. In other words, job satisfaction was higher when work climate was better, job competence was higher or when work facilities were better. Job satisfaction was generally lower in part of male dental technicians than female ones. Considering the fact that job satisfaction is most influenced by work climate, more careful attention should be paid to assistant technicians who while on duty, usually have not so good relationship with seniors or colleagues. Those technicians also usually have few or no opportunity of obtaining latest knowledge or skills, so they should be allowed time for seminars or lectures in which such knowledge or skills are educated. It is also important to raise assistant technicians' pride about their job by empowering them by authorization or giving more remuneration or other rewards for their improved job competence.
Finite element analysis of stress distribution on supporting bone of posterior implant partial dentures by loading location
Son, Sung-Sik ; Kim, Young-Jick ; Lee, Myung-Kon ;
Journal of Korean Acedemy of Dental Technology, volume 29, issue 1, 2007, Pages 93~101
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.
Analysis of Relationship Between Dental Health Condition and Eating Habit
kim, Jeong-Sook ; Lee, Jong-Do ; Jung, Hyo-Kyung ;
Journal of Korean Acedemy of Dental Technology, volume 29, issue 1, 2007, Pages 103~119
The survey on dental health condition and eating habit of local residents in Daegu and Kyungbuk had been conducted. Through the analysis of influence of dental health condition on eating habit I could get the following result. The number of subjects of survey is 630. The period of survey is from June 2006 to September 2006. 1. General quality of subjects is that forty-four point four percent of subjects are male and fiftyfive pointsix percent are female. The age of thirty point one percent of subjects is between 20 and 29. Fifty-six point two percent of subjects are married. Fifty-one point four percent of subjects have above bachelor degree. Monthly income of forty-four point eight percent of subjects is less than one million won. Twenty-four point four percent of subjects are students. Fifty-five point seven percent of subjects are living in big cities. 2. Forty-seven point seven percent of male and fifty-one point eight percent of female answered their subjective dental health condition is bad. Marital status, age and academic background have relationship with answer. Forty-three point nine percent of married subjects and forty-one point five percent of divorced or bereaved subjects said they have bad dental health condition. The older he is or the lower academic background he has subjects think they have bad dental health condition. Forty-seven point four percent of non-educated subjects answered their dental health condition is bad. Forty-six percent of self-employed subjects and subjects who live in the country have tendency to think their dental health condition is bad. 3. About eating habit knowledge, male's knowledge of 2.03
0.20 is lower than female's of 2.08
0.21. This shows there is statistically significant difference(p<0.01). 4. There is significant relationship between subjective dental health condition and health condition of subjective. This means subject who has better health condition has also better dental health condition(37.5%). About subjective dental health condition, subject who eats restoratives has worse dental health condition. This shows there is a relationship between dental health condition and eating restoratives(p=0.004) and subject who works out steadily has better dental condition. 5. About relation between dental health condition and eating habit, subject who eats vegetables has worse dental health condition by fifty point seven percent. As cross tabulation result, p-value is 0.002. In level of significance of 0.05, there is statistically significant difference in eating habit. 6. It seems that eating habit has an effect on marital status, age, academic background, income and also on dental prosthetic treatment situation. Many subjects think their dental health condition is bad. About eating habit, subjects who eat meat have better dental health condition. Subjects who drink green tea and fruit juice has better dental health condition than who drink coffee and Balanced diet is good for dental health condition. As eating habit is important for developing dental health, government should make a proper program. Dental health education program especially for elderly, low-eduacted, residents in the country and poor people should be developed. Government, dental health organization, dental health specialist, associated research institution and people work in the press should be concerned and devote to improve quality of life. Primary prevention education will help for dental health.
Superhydrophilicity of Titania Hybrid Coating Film Imposed by UV Irradiation without Heat-treatment
Kim, Won-Soo ; Park, Won-Kyu ;
Journal of Korean Acedemy of Dental Technology, volume 29, issue 1, 2007, Pages 121~131
A preparation process's conditions of aqueous sol which contains anatase-type nano titania particles with photocatalyic properties was established by using Yoldas process, so called, DCS(Destabilization of Colloidal Solution) process in this study. And crystal size change and phase transformation of titania particles in aqueous titania sol depending on reaction conditions was investigated by a light scattering method and XRD analysis of frozen dried powders, respectively. This sol with photo catalytic nano titania particles was used to the following hydrophilic hybrid coating film's fabrication and its properties was evaluated. Subsequently, for coating film using the above mentioned aqueous titania sol, non-aqueous titania sol was prepared without any chemical additives and its time stability according to aging time was investigate. By using the above mentioned aqueous titania sol and non-aqueous sol, a complex oxide coating sol for metal and ceramic substrate and a organic-inorganic hybrid coating sol for polymer substrate was prepared and it's hydrophilicity depending on UV irradiation conditions was evaluated. As a conclusions, the following results were obtained. (1)Aqueous titania sol The average particle size of titania in formed aqueous titania sol was distributed between 20
90nm range depending on reaction conditions. And the crystal phase of titania powders obtained by frozen drying method was changed from amorphous state to anatase and subsequently transformed to rutile crystal phase and it is attributed to concentration gradient in aqueous sol. (2)Non-aqueous titania sol Non-aqueous titania sol was prepared using methanol as a solvent and a little distilled water for hydrolysis and nitric acid as a catalyst were used. The obtained non-aqueous titania sol was stable at room temperature for 20 days. Additionally, non-aqueous titania sol with addition of chealating reagent such as acethylaceton and ethylene glycol prolonged the stability of sol by six months. (3)Complex sol and hybrid sol with super hydrophilicity The above mentioned aqueous titania sol as a main photocataylic component and non-aqueous titania sol as a binder for coating process was used to prepare a complex sol used for metal, ceramic and wood material substrate and also to prepare the organic-inorganic hybrid sol for polymer substrate such as polycarbonate and polyethylene, in which process APMS(3-Aminopropyltrimethoxysilane), GPTS(3-Glycidoxypropyl-trimethoxysilane) as a hydrophilic silane compound and HEMA(2-Hydroxyethyl methacrylate) as a forming network in hybrid coating film were used. The hybrid coating film such as prepared through this process showed a superhydrophilicity below 1
depending on processing conditions and a pencil's hardness over 6 H.
Analysis of castability in c.p.Ti according to casting conditions
Hwang, Seong-Sig ; Kwon, Seog-Suk ;
Journal of Korean Acedemy of Dental Technology, volume 29, issue 1, 2007, Pages 133~138
In this study, the castability and of commercially pure titanium(c.p.Ti) grade according to the casting condition which are the vacuum condition in casting machine and mold temperature of investment, was investigated. Argon-arc melt/centrifugal casting machine was used for casting the specimens. The microstructure and mechanical properties were evaluated by using optical microscope. The results were as follows; 1. It could make a sure that there's relatively not much defect of casting body of c.p.Ti according to the deference of air pressure. 2. It could make sure that it formed porosity on the surface inside of the casting body of c.p.Ti according to deferent temperature. and on excellent castability was below
3. As the mold temperature of investment was increased, the lamellar structure of phase and coarse grains were shown, especially under 42MPa.
임프란트 보철물 제작과정에 있어 심미적인 구성요소
Journal of Korean Acedemy of Dental Technology, volume 29, issue 1, 2007, Pages 141~145
Nobel guide를 이용한 minimum invasive surgery와 surgical template & temporary 제작과정에 대하여
Journal of Korean Acedemy of Dental Technology, volume 29, issue 1, 2007, Pages 147~154
신개념의 ALL-CERAMIC RESTORATIONS (TOP-CERAM)
Journal of Korean Acedemy of Dental Technology, volume 29, issue 1, 2007, Pages 155~162