• Transactions on Electrical and Electronic Materials
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• 제18권3호
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• pp.148-150
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• 2017

For the improvement of the anti-fouling features of porcelain electrical insulators, in this study, the surface of an insulator was coated with a functional material to expand the insulator's self-cleanness. The anti-fouling and mechanical features of the functional film coating of ceramic substrates made from components like an electrical insulator were analyzed. The coating methods that were used were spray coating, dip coating, and fabric coating. Following the coating, the contact angle of the coated surface was measured, revealing that the spray coating method offered the lowest angle ($13.7^{\circ}$) and a strong hydrophilic feature. The anti-fouling analysis showed that the anti-fouling features improved as the contact angle decreased. The mechanical properties - hardness and adhesion - were both excellent at 9H and 5B, respectively, regardless of the coating method that was used.

• 박물관보존과학
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• 제16권
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• pp.122-137
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• 2015

국립중앙박물관 소장 백자수주(덕수5531)는 1915년에 구입한 것으로 전체적으로 운룡문이 투각되어 있고 반파된 상태로 수구부분은 이미 복원된 상태이다. 본 논문은 수작업식 보존처리의 단점을 보완하기 위해 백자수주의 결손부분인 운룡문을 3D 스캐닝과 프린팅을 이용하여 복원하는 방법에 대하여 다루었다. 이에 대한 선행연구로서 이미 상용화된 6종의 출력 재료에 대하여 강도 실험을 실시하고, 수작업용 복원재료인 에폭시퍼티(Quick Wood^®)와 에폭시(Araldite AY103+HY956^®)의 강도와 비교하였다. 디지털 기술을 이용한 복원형 제작은 수작업보다 적은 시간과 노력으로 더 정확한 형태를 얻을 수 있음을 확인하였으며, 무엇보다도 비접촉식 복원방식이기 때문에 보존처리 과정에서 있을 수 있는 위험요소를 줄일 수 있었다. 특히, 디지털 원형 파일을 기록물로 남기고 이를 부차적인 콘텐츠로 사용할 수 있는 점이 주목할 만하다. 그러나 유물 보존처리 과정에 적용할 디지털 기술의 적용방법, 출력재질에 대한 평가와 적용, 출력물의 정형, 접합 및 표면채색 방법 등은 향후 좀 더 연구해야 할 과제이다.

• 대한치과기공학회지
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• 제23권2호
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• pp.211-221
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• 2002

The purpose of this study was to analyze the commercial paste opaque products currently available in domestic of foreign as well as domestic, such as Duceram Plus(DU; Ducera Dental GmbH, Germany), VMK 95(VM; Vita Co., Germany), Noritake EX-3(EX; Noritake Co., Japan) and Ceramax(CE; Alphadent Co., Korea). They were characterized in thermal expansion coefficient, particle size distribution, viscosity and solvent using thermomechanical analyzer, particle size analyzer, rheometer and infrared spectrophotometer. Experimental results are as follows; Firstly, thermal expansion coefficients were determined $13.9{\times}10-6/^{\circ}C$ for DU, $14.3{\times}10-6/^{\circ}C$ for VM, $13.3{\times}10-6/^{\circ}C$ for EX, and $14.0{\times}10-6/^{\circ}C$ for CE. Secondly, percent of partice size below $1{\mu}m$ were 12% for DU, VM and CE, and 13% for EX, percent between $1{\mu}m$ and $5{\mu}m$ were 42% for DU, 42% for VM, 38% for EX, and 61 % for CE, percent between $5{\mu}m$ and $10{\mu}m$ were 21 % for DU, 24% for VM, 20% for EX, and 18% for CE, and over $10{\mu}m$ were 25% for DU, 22% for VM, 29% for EX, 9% for CE. Thirdly, the basic composition of the solvent in all of the commercial paste opaques were determined as ethylene glycol from FT-IR investigation. Lastly, measured viscosities were 1798 cp for DU, 536 cp for VM, 1110 cp for EX, and 721 cp for CE.

• 대한치과보철학회지
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• 제42권1호
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• pp.49-57
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• 2004

Statement of problem : The increased awareness of esthetics in dentistry has brought the esthetic consideration in prosthetic restorations . Dental ceramics offer better esthetics for use of prosthetic restorations. Unfortunately, dental ceramic materials are not always the most suitable candidate materials since their inherently brittle nature. In recent years, basic research in ceramic science has led to the recognition or several approaches to strengthen and to enhance esthetics of ceramics. Several all ceramic systems use ceramic core and porcelain build up structures . Ceramic cores influence to strength of all ceramic crowns . So the strength of ceramic cores is important to all ceramic crowns. Purpose : The purpose of this study is to estimate the flexural strength of ceramic cores in some all ceramic systems. Material and method : A biaxial flexure test was conducted on three groups(Cergo, Empress 2, In-Ceram). Each group consisted of 30 discs of nearly identical dimension with a 0.5mm, 1.0mm, 1.5mm thickness and 12mm in diameter. The fracture load was recorded by Instron. Analysis of valiance(ANOVA) and Tukey's tests were performed using SAS statistical software. Results : 1.5mm thickness of specimens were significantly stronger than 0.5mm and 1.0mm thickness of specimens in Cergo and In-Ceram. But each sepecimen group of Empress 2 was no significantly strength by thickness. In order of In-Ceram, Empress 2 and Cergo has significantly stronger strength in the same thickness. Conclusion : In-Ceram is the strongest ceramic material in 3 materials. All the materials can be used according to the required characters.

• 대한치과의사협회지
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• 제52권2호
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• pp.96-104
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• 2014

The aim of this study was to investigate the frequency of positive patch test reaction to dental materials in patients with oral mucosal diseases. Epicutaneous patch test was performed in 110 patients with oral mucosal diseases; 41 patients with oral lichen planus(OLP), 44 patients with burning mouth syndrome(BMS), 25 patients with other oral mucosal diseases including recurrent aphthous ulcer and mucous membrane pemphigoid. The obtained results were as follows: Oral gold restorations were most common in patents with oral mucosal diseases and porcelain fused metal crown, implant appeared in the order. 33 of 110 patients did not appear skin reactions (negative, 30%) and 77 patients (positive, 70%) had skin reactions including redness, rash, blisters. Dental materials causing positive reaction to patch test were mainly as gold-sodium-thiosulfate (26.7%), nickel sulfate(Ni) (22.7%), cobalt chloride(Co) (14.7%), palladium chloride(Pd) (11.9%), potassium dichromate (10.7%) in order, respectively. In conclusion, old metal restorations could be the cause of oral mucosal diseases and epicutaneous patch test could be used as a tool to improve the oral conditions.

• 대한치과보철학회지
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• 제48권4호
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• pp.273-279
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• 2010

연구 목적: 본 연구의 목적은 전통적인 금속 도재관과 열-가압을 이용한 금속-도재관의 변연 적합도를 비교하는 것이다. 연구 재료 및 방법: 상악 제1소구치 레진 치아를 교합면 2.0 mm, 협, 설면과 인접면을 1.0 mm 두께로 삭제하였으며, 변연 형태는 chamfer margin으로 그리고 축면 경사는 6도 taper로 삭제하였다. 삭제한 레진치를 복제하여 금속 다이 20개를 제작하였고, 이 금속 다이를 인상 채득하여 작업을 위한 석고 다이를 제작하였다. 금속 도재관과 $PoM^{(R)}$ 시스템 (Ivoclar vivadent., Liechtenstein)의 두 그룹으로 나누어 금속 코핑을 각각 10개씩 총 20개를 제작하였으며, 광학 현미경을 이용하여 변연 간격을 측정하였다. 도재 축성 후, 위와 동일한 방법으로 변연 간격을 측정하였다. 통계 처리는 Wilcoxon Signed Ranks test와 Mann Whitney U test를 이용하여 분석하였다. 결과: 본 연구의 결과는 다음과 같다. 1. 금속 도재관은 코핑 상태 ($64.93{\pm}12.48\;{\mu}m$)와 도재 축성 후 ($63.43{\pm}12.86\;{\mu}m$)의 변연 간격에 유의성 있는 차이를 보이지 않았다. 2. $PoM^{(R)}$ 시스템은 코핑 상태 ($50.00{\pm}12.28\;{\mu}m$)와도재축성후($56.72{\pm}13.80\;{\mu}m$)의 변연 간격에 유의성 있는 차이를 보이지 않았다. 3. 금속 도재관과 $PoM^{(R)}$ 시스템 변연 간격은 유의성 있는 차이를 보이지 않았다. 결론: $PoM^{(R)}$시스템은 왁스 소결법을 이용해 변화가 적은 기술적인 이점이 있으며, 세밀한 기술을 요구하는 축성 방법과는 대조적으로 왁스 성형으로 도재의 완전한 형태를 만들 수 있는 편리함을 제공하는 장점을 가진다. 본 연구 결과와 이런 장점을 토대로 앞으로 임상적 사용을 고려해 볼 수 있을 것으로 사료된다.

• 농업생명과학연구
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• 제45권1호
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• pp.59-66
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• 2011

본 연구는 화병의 재질과 절화보존제 처리 여부가 절화의 화색, 엽색, 그리고 화경에 미치는 영향을 구명하기 위해 조사하였다. 절화 장미 (Rosa hybrida) 'Aqua'와 'Corvernet' 및 거베라 (Gebera jamesonii) 'Honeymoon'과 'Golden Time'을 수돗물 또는 절화보존제 용액이 들어있는 유리, 자기 및 옹기 화병에 꽂고 화색, 엽색, 최대화경의 변화를 측정하였다. 처리 8일 후 화색에 있어서 장미 'Aqua'의 ${\Delta}E$값은 옹기와 자기화병의 보존제 처리에서 작게 나타났다. 장미 'Covernet'은 옹기화병의 보존제 처리에서 ${\Delta}E$값이 가장 작았고, L값도 처리 직전의 꽃잎 (대조구)과 가장 근접하였다. 거베라 'Honeymoon'의 경우 절화보존제 처리와 옹기화병에 의해 ${\Delta}E$값이 가장 작게 나타났고, a와 b값도 58.81, 34.29로 대조구와 가장 유사하였기 때문에 옹기화병에 꽂은 절화의 화색이 처리 직전의 화색과 유사하였다. 거베라 'Golden Time'의 ${\Delta}E$값은 옹기화병이 자기나 유리화병보다 크게 작았는데, a값은 옹기화병의 보존제 처리에서 -7.81로 가장 근접하였고, b값 역시 옹기화병에서 높게 나타났다. 장미의 엽색에 있어서는 옹기화병의 보존제 처리에서 L, a, b값이 처리 직전의 잎과 가까웠고 ${\Delta}E$값은 옹기화병에서 3.25로 나타나 자기나 유리에 비해 작았다. 화경은 장미 'Covernet'과 거베라 'Golden Time' 모두 옹기의 보존제 처리에서 크게 나타났다. 이상의 결과로 보존용액에 절화보존제를 첨가함으로써 미생물 번식을 감소시켜 절화수명이 연장되어 장미와 거베라의 품질 및 신선도를 증가시킬 수 있고, 다공질의 옹기 화병을 사용하여 통기성을 증가시키면 화색과 엽색을 좀 더 좋게 하고, 화경도 증가시킬 수 있을 것으로 판단된다.

• 대한치과기공학회지
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• 제28권1호
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• pp.177-198
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• 2006

This study purposed to offer basic data for safety education of the dental laboratory technology after the investigation of how much the students in the dept. of dental laboratory technology are aware of the danger of each instrument, equipment or laboratory procedure that they use during laboratory and how much they demand safety education for this. The objects for this study were 423 students who were in the dept. of dental laboratory technology. In this regard, four colleges which have the dept. of dental laboratory technology were randomly selected to do a questionnaire survey. SPSS 12.0 was used to analyze 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 partial denture, they considered casting, polishing the casting body, polishing denture and burn out were most dangerous in order. As for the production process of a full denture, what they regarded as the most dangerous in order was polishing denture, deflasking and wax wash. Regarding the laboratory procedures of porcelain material, casting, trimming casting body, polishing porcelain material and burn out were the most dangerous procedures that they perceived. With regard to materials for use, alcohol, polishing, metal and wire were the most dangerous ones they thought. As for the handling characteristics of each material, small towns showed a higher demand for safety of the handling characteristics of alcohol. In terms of school year and sex, juniors and girls had higher scores in the demand for safety of the handling characteristics of acid. Regarding the handling characteristics of each equipment and instrument, all of small towns, juniors and girls showed the highest demand for safety of the handling characteristics of alcohol lamps. With regard to scores in the demand for safety of other characteristics, all of small towns, juniors and girls had the highest demand for safety of emergency treatment. Concerning the demand for safety education by the completion of safety education, in terms of each material, highest was the demand for safety of acid from the group which completed safety education. In regard to equipments and instruments, when it came to the demand for safety of the handling characteristics of casting machine, the educated group's demand for safety of acid was higher. Regarding other characteristics, the group which was not educated gained higher scores in the demand for safety of emergency treatment. 11. In all areas(materials, machines and others), small towns, girls and juniors showed higher scores in the demand for safety. Based on the above results, it was found that when students conduct the laboratory of dental technology, they would think that many materials, instruments or equipments for use 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 the lowest 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 every laboratory and each process, safety accident types and accident risk factors should be investigated to develop educational materials for this. Moreover, it is required to open safety education as a single course of study or insert safety contents of all materials and machines into the class of dental laboratory instrument or dental materials for the purpose of a systematic and thorough safety education to prevent a safety accident during laboratory.

• 대한치과보철학회지
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• 제33권4호
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• pp.634-644
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• 1995

The purpose of this study is to evaluate the color differences in the In-Ceram according to coping thickness and various abutment core materials ; amalgam, precious alloy, composite resin, non-precious alloy. After the porcelain was built up on the In-Ceram coping at the thicknes of 0.3mm and 0.5mm then it was cemented with glass ionomer cement to the post & core materials. The following results were obtained. 1. There were significant differences in the $L^*$ values $a^*$ and $b^*$ values in the cementation of different cores, to the In-Ceram(P<0.01). $L^*$ values were not significantly different between the composite resin to the In-Ceram and the $a^*\;b^*$ values were not significantly different between the amalgam and the non-precious alloy. 2. All of cementations of In-Ceram to the core materisal had color difference(${\Delta}E^*ab$) compared to the In-Ceram. In the 0.3mm thickness of the In-Ceram copping non-precious alloy indicated the greatest value, while the composite resin core showed the lowest value with a thickness of 0.5mm In-Ceram copping. 3. By controlloing the In-Ceram coping thickness $L^*$ value was significatly different(P<0.01), but not in $a^*$ and $b^*$ values. 4. In an amalgam, precious & non-prcious alloys there was a 1,74 to 3.06 range color difference in the controlled thickness of In-Ceram coping at the thickness of 0.3mm and 0.5mm. The above results suggest that the requirement of the sufficient thickness of In-Ceram coping and the suitable core material in order to get an estheti restoration by In-Ceram and also to intercept the original core color.

• 대한치과기공학회지
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• 제9권1호
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• pp.5-19
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• 1987

The factors which impact on the productivity of medical organization are technique, manager, raw materials, management style, manpower structure, job construction, and so on. Human resources is the most important factor among them, but the productivity of serice organization can not be measured easily. The purpose of this study was to verify the effect of laboratory status, the degree of job cognition, and stress on the productivity of dantal prosthetic products, and to fine out the factors which impact on the productivity. The results were as follows: 1. The job characteristice of crown bridge laboratory part and porcelain laboratory part similar to each other. Also partial denture laboratory part and complete denture laboratory part were similar to each other. But that of orthodontic laboratory part was different from other. 2. the degree of job cognition made significant difference statisfically according to job characteristics of each dental laboratorise. 3. The correlation coefficient between job cognition of dental laboratory technician and workshop environment was.23, but the correlation between job cognition job stress appeared reversely, its coefficient was-.17. 4. The productivity of technician engaged in dental laboratory was much heigher than that of technician engaged in dental clinical laboratory room, and each were different in the degree of job cognition. 5. the most important factors which impact one the performance productivity of dental laboratory technician were the fact whether he married or not and his status.