• 대한치과기공학회지
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• 제1권1호
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• pp.31-36
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• 1979

• 대한치과기공학회지
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• 제3권1호
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• pp.21-24
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• 1981

• 대한심미치과학회지
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• 제9권1호
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• pp.62-67
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• 2000

• 대한치과기공학회지
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• 제2권1호
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• pp.47-49
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• 1980

• 대한치과보철학회지
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• 제31권1호
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• pp.1-10
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• 1993

The purpose of this study was to evlauate the microleakage of 3 dentin bonding agents using different dentin pretreatment method under simulated physilogic pressure in cementing the porcelain laminate veneer. Noncarious 60 human maxillary molars were selected and randomly assigned to 4 groups of 15 each. The group with the margin placed on the enamel was classified as the control and the groups with the margin placed on root surface were subdivided into 3 groups according to the dentin bonding agents used. The group using All Bond 2 was classified as experimental group 1, the group using Scotchbond MP was classified as experimental group 2, and the group using Gluma was classified as experimental group 3. Roots were removed at 3mm below the cementoenamel junction, and reductions of the teeth for the porcelain laminate veneer were done on the mesial 1/2 of the buccal surface of each teeth. The pulp was extirpated and the pulp chamber was cleaned with 37% phosphoric acid for the patency of dentinal tubule. Under simulated physiologic pressure, porcelain laminate veneers were cemented to the teeth using each dentin bonding agent and luting cement. After cementation, all samples were stored at 36t in water for 24 hours and thermocycled for 1500 cycles, then immersed in 0.5% basic fuchsin solution and the teeth were sectioned longitudinally by using diamond saw and the extent of microleakage was measured. The following results were obtained, 1. Microleakage was observed in a few samples of control group but all the samples of experimental groups. 2. The control group showed the less extent of microleakage than the experimental groups. In experimental groups the experimental group 1 & the experimental group 2 showed similiar extent of microleakage and the experimental group 3 showed the greater extent of microleakage than other groups. Conclusively, practicing the porcelain laminate veneers in the clinic, although the margin of the porcelain laminate veneer should be placed on enamel, in the case that it is inevitable to place the margin of the porcelain laminate veneer on the root surface, it is recommened to use dentin bonding agents which use no dentin pretreatment or a dentin pretreatment which can leave the smear plugs.

• 대한치과보철학회지
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• 제37권6호
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• pp.756-766
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• 1999

This study was performed to evaluate effect on color and opacity of 3 different copy-milled In-Ceram cores by glass infiltration and porcelain veneering. Color was evaluated by the $CIEL^*a^*b^*$ readings were recorded with a Colorimeter, Color difference value(${\Delta}E^*_{ab}$) was calculated and opacity was represented by the contrast ratio. The variance of each color parameter ($L^*,\;a^*,\;b^*$), color difference value, and opacity change after glass-infiltrated and after veneered with porcelain was compared. Three experimental groups were fabricated as follows. Group 1 (Alumina core) 15 Alumina blanks was infiltrated with originally marketed glass (A1) and veneered with porcelain(A1) Group 2 (modified Alumina core) : 15 Alumina blanks was infiltrated with its associated glass(S11) and veneered with porcelain(A1) Group 3 (Spinell core) : 15 Spinell blanks was infiltrated with originally developed glass(S11) and veneered with porcelain(A1). The results were as follows: 1. After glass infiltration, $L^*$ value showed decrease, $a^*$ value showed decrease only group 1(p<0.001) and $b^*$ value showed increase on group 1, increase on group 2, 3(p<0.001). 2. After porcelain veneering, $L^*$ value showed decrease(p<0.001), $a^*$ value showed increase on group 1, decrease on group 2(p<0.05) and $b^*$ value showed decrease on group 1, increase on group 2, 3 (p<0.001). 3. ${\Delta}E^*_{ab}$ between before and after glass infiltration was more than 13.77, and between after glass infiltration and after porcelain veneering more than 19.63. 4. After glass infiltration and porcelain veneering, Alumina showed the lowest $L^*,\;a^*$ value and highest $b^*$ value among 3 different groups (p<0.05). ${\Delta}E^*_{ab}$ between group 1-2, 1-3 was higher than that of group 2-3. 5. After glass infiltration, opacity showed decrease, Group 1 had the highest opacity(p<0.05), but no significant differences between group 2 and 3. Above results suggest that glass infiltration and porcelain veneering effects on color and opacity of In-Ceram core, and that modified In-Ceram Alumina uses single crowns or bridges like In-Ceram Spinell.

• 대한치과보철학회지
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• 제43권5호
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• pp.587-598
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• 2005

Statement of problem: Ceramic restorations should be made of porcelain layers of different opacity, shade, and thickness in order to provide a natural appearance. Lithium disilicate glass-ceramic system has superior color reproducibility, because it uses the ceramic ingot which is similar to teeth shade and uses the staining technique and layering technique. However, staining technique has a fault of discoloration. Also, porcelain is divided core and dentin layer, it is not enough to study about the influence of porcelain layer thickness and shade on the shade of ceramic restorations. Purpose: The purpose of this study was to evaluate the influence of porcelain layer thickness and color on the final shade of ceramic restorations. Materials and method: The CIE $L^*a^*b^*$(CIELAB) values of 72 assembled specimens, each consisting of 3 discs (enamel porcelain 0.2 mm/dentin porcelain -1.2, 0.9, 0.7, 0.5 or 0.3 mm/ceramic core -0.3, 0.5, 0.7, 0.9 or 1.2 mm, diameter is 1.0 mm) were evaluated with a spectrophotometer (Model Chromaview 300, Spectron Tech Co, Korea) for the shade A1, A2, A3 and A4. Distilled water (refractive index: 1.7) was used to attain optical contact between the layers. White, white gray, and white brown backgrounds were used to assess the influence of the background on the final shade. And the mean color difference value$({\Delta}E)$ was calculated. Results and conclusion: The results obtained from this study were as follows. 1. There was a significant correlation between the thickness ratio of the ceramic core/dentin porcelain system and $L^*,\;a^*\;and\;b^*$ values when the total thickness of specimen combination was smaller than 1.4 mm(P<0.05). 2. The specimen which the ceramic core thickness was more than 0.7 mm had the best masking effect against background colors. 3. The mean color difference value$({\Delta}E)$ is smaller than 2 $({\Delta}E<2)$ when the ceramic core thickness was larger than 0.7 mm and the total thickness of specimen was more than 1.4 mm.

• 치위생과학회지
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• 제9권4호
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• pp.405-412
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• 2009

본 연구는 도재소부용 비귀금속에 Au 코팅 층을 형성하고, Au 코팅 층이 금속-도재의 결합력에 미치는 영향을 알아보고자 2출 굴곡 시험 후에 SEM/EDS 방법으로 조사하여 비교하였다. 1. Ni-Cr ally 군과 Co-Cr alloy 군, 그리고 Ti 군의 절단면 시편의 전자현미경 사진에서 Au 코팅 층은 산화층의 확산을 제어하는 것으로 관찰되었다. 2. 2축 굴곡 시험 후에 EDS 분석 결과 Ni-Cr alloy 군과 Co-Cr alloy 군에서 Si 함량은 Au 코팅 층을 형성한 시편에서 약간 감소하였고, 결합실패의 형태는 cohesive failure와 adhesive failure가 혼재된 양상으로 관찰되었다. 3. Ni-Cr alloy 군과 Co-Cr alloy 군에서 Au 코팅 층은 도재-금속 결합력에 미치는 영향은 미미하였다. 4. Ti 군의 결합실패 형태는 Ni-Cr alloy 군과 Co-Cr alloy 군에 비해서 adhesive failure 양상이 두드러지게 관찰되었고, Au 코팅 층은 도재-금속 결합력에 영향을 미치지 않았다. 이상의 결과 비귀금속에 적용한 Au 코팅은 산화층의 확산을 제어 하는 것으로 관찰 되었으나, 금속-도재 간의 결합력 증징에 미치는 효과는 미미하였다. Au 코팅을 이용하여 금속-도재 간의 결합력 증진을 위해서는 많은 연구가 지속되어야 할 것으로 사료된다.

• 대한방사선기술학회지:방사선기술과학
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• 제31권4호
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• pp.323-327
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• 2008

자기양담낭은 담낭 벽에 칼슘이 침착되는 드문 질환이며, 만성담낭염에 의해 벽에 석회화가 일어나거나 결석에 의해 담낭관이 폐색되면서 발생하는 것으로 보고 되고 있다. 자기양담낭은 일반적으로 담낭암을 동반하므로 담낭암을 예방하기 위해 일차적으로 담낭 절제술이 시행된다. 저자들은 증상이 없는 석회화된 담낭을 초음파 검사와 복부 단순방사선검사 및 복부 전산화단층검사를 통해 확인하였고 문헌고찰과 함께 보고하고자 한다.

• Transactions on Electrical and Electronic Materials
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• 제9권4호
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• pp.147-150
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• 2008

Porcelain suspension insulators aged for 1, 5 and 10 years on Korean transmission lines and new insulators are tested for autoclave expansion. The compressive strength of the insulators aged in an autoclave with conditions of $250\;^{\circ}C$ and at 20 atm for 30 minutes, was about $7.6\;kgf/mm^2$, which is close to that measured on insulators aged for 10 years in the field. From simulation results, the cement displacement changed linearly with temperature. At a temperature of $200\;^{\circ}C$, the shear stress was approximately $7\;kgf/mm^2$; a stress that is brought about by a 0.07 % expansion of the cement. It is evident that the cement would fracture at a 0.07 % expansion, because the cement has about 7 to $9\;kgf/mm^2$ flexure strength. A turning point in the shear stress with mechanical load occurred at 0.02 % cement expansion. From an analysis of the porcelain body it is shown that there is sufficient margin of strength to guard against fracture of the porcelain body even for a cement expansion more than 0.12 %.