• 구강회복응용과학지
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• 제18권3호
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• pp.179-184
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• 2002

To compare surface roughness in various porcelains and know effects of condensation, We used Ceramco dentin porcelain, Creation dentin porcelain, Creation margin porcelain, Vintage margin porcelain, Vintage dentin porcelain, and Vita dentin porcelain, and built up the powders with condensation or not, and then fired according to the instructions with porcelain furnace( Dekema, Germany ). We polished the samples step by step using the porcelain adjustment kit( Shofu Inc., Japan ), and then measured, compared and analysed Ra, Rz, and Rmax with Surftest SV-400( Mitutoyo Co., Japan ). 1. With condensation, roughness is significantly increased in Ceramco dentin porcelain (p<0.05) and decreased in Vita dentin porcelain(p<0.05). 2. In Ra, Vita dentin porcelain is significantly the roughest and Creation margin porcelain is rougher than others in no condensation, (p<0.05), and there is no difference under condensation. 3. In Rz, Vita dentin porcelain is significantly the roughest and Creation margin porcelain is rougher than others in no condensation, and Creation margin porcelain is significantly the roughest and Creation dentin porcelain is rougher than others under condensation(p<0.05). 4. In Rmax, Vintage dentin porcelain is significantly the roughest and Creation margin porcelain is rougher than others in no condensation, and Creation margin porcelain is significantly the roughest than others under condensation(p<0.05).

• 대한치과기공학회지
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• 제2권1호
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• pp.47-49
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• 1980

• 대한치과기공학회지
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• 제22권1호
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• pp.79-88
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• 2000

The objective of this finite element method study was to analyze the stress distribution induced in a maxillary central incisor Ni-Cr base metal coping ceramic crowns with various margin design. Margin designs of crown in this experiment were knife-edge metal margin on chamfer finishing line of tooth preparation(M1), butt metal margin on shoulder finishing line(M2), reinforced butt metal margin on shoulder finishing line(M3), beveled metal margin on bevelde shoulder finishing line(M4). Two- dimensional finite element models of crown designs were subjected to a simulated biting force of 100N which was forced over porcelain near the lingual incisal edge. Base on plane stress analysis, the maxium von Miss stresses(Mpa) in porcelain venner was 0.432, in metal coping was 0.579, in dentin abutment was 0.324 for M1 model, and M2 model revealed in porcelain was 0.556, in metal coping was 0.511, in dentin was 0.339, and M3 model revealed in porcelain was 0.556, in metal coping was 0.794, in dentin was 0.383 for M4 model. All values of each material in metal-ceramic crown were much below the critical failure values.

• 대한치과기공학회지
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• 제32권1호
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• pp.17-21
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• 2010

This experimental study was to determine the fitness in each cervical margin of reusing porcelain gold alloy. The gold alloy used in this experimental study was a Au-Pt-Pd alloy (BDCG-898, Bukwang Inc, Korea) for the fabrication of porcelain fused to metal crown. Twenty-five copings were divided into the five groups. And the group A, B, C, D and E were cording successively according to the frequency of reuse to five times. Each specimen was reused without adding new metal. The experimental results were as follows: 1. The group A, B, C showed good fitness in each cervical margin. 2. The group D got good fitness in labio and linguo cervical margin, but the mesio and disto cervical margin showed more than $40{\mu}m$ 3. The group E showed worse fitness than the other groups in each cervical margin.

• 대한치과보철학회지
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• 제33권2호
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• pp.198-209
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• 1995

In order to evaluate the fitness and the degree of rounding of porcelain margins in collarless metal cermic restorations, collarless metal ceramic restorations were fabricated with shoulder margins of 90 and 120 degress, each consisting of ten specimens, on master dies through the direct lift technique. And ten metal ceramic restorations with a shoulder 90 degrees were fabricated. All specimens were embedded in resin and sectioned longitudinally. The sections were observed under a stereomicroscope and photographed(${\times}$200). The labial marginal gap between the die and the porcelain margin were measured with a scale. The space between the porcelain margin and the die, that is formed from marginal rounding and cementation were calculated with a computer coordinating area curvimeter. The following results were obtained. 1. There was no statistical difference between the fitness of porcelain margin of collarless metal ceramic restorations and marginal fitness of metal ceramic restoration. 2. There was no statistical difference between a shoulder of 90 and 120 degrees in the fitness of porcelain margin of collarless metal ceramic resorations. 3. Collarless metal ceramic restorations with a shoulder of 90 degrees and 120 degrees showed significantly more labial marginal rounding than metal ceramic restorations. 4. There was no statistical difference between a shoulder of 90 and 120 degrees in rounding of porcelain margin of collarless metal ceramic restorations. According to the results, rounding of porcelain margins can be observed in collarless metal ceramic restorations. Thus, there is a need for improvement in dental materials and techniques to minimize this problem, Furthermore, care should be exercised during the clinical procedure.

• 대한치과기공학회지
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• 제5권1호
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• pp.27-30
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• 1983

적은 경비로써 보다 양호한 치경부의 적합과 Shade를 얻고 치경부의 변색을 막기 위하여 도재소부용 귀금속과 비금속, 그리고 귀금속과 비금속위에 도금을 하는 4가지 유형으로 나누어 실험하였던 바 다음과 같은 결과를 얻게 되었다. 1. 도재소부용 귀금속으로 치관전체를 주조하는 경우는 수축율이 적고 연성이 뛰어나 경비가 많이 소요된다. 2. 비금속으로 치관전체를 주조하는 경우는 경비는 저렴하나 치경부의 적합성이 금속에 따라 차이가 있으며 그 중 Gemini II가 가장 우수하였다. 3. 비금속으로 치관 전체를 주조하고 10K의 Gold로 도금하는 경우는 적합성에서는 비금속과 동일하나 도금이 고리게 되지 않고 Shade에서도 별 효과가 없었다. 4. 치관의 윗부분은 비금속으로 먼저 주조하여 Degassing한 후 나머지 2mmwjd도의 치경부를 귀금속으로 주조하는 경우는 치경부의 적합성은 귀금속과 동일하게 우수하고 경비 또한 매우 저렴하였다.

• 대한치과보철학회지
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• 제37권6호
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• pp.800-808
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• 1999

To compare several porcelains made by various manufacturers in shrinkage after firing and investigate the effect of condensation on shrinkage, specimens were prepared and the volume of each body was measured by the phase-shifting profilometry. Baseplate wax was cut by $2.5cm{\times}2cm$ and cast in nonprecious metal(Verabond, U.S.A.), then any surfaces of specimens were abrased and polished on the SiC abrasing papers, preparing 120 specimens. Specimens were divided into six groups according to the porcelain used, and the porcelain used in each group were as follows. Group I : Ceramco dentin porcelain Group B : Creation dentin porcelain Group III : Creation margin porcelain Group IV : Vintage margin porcelain Group V : Vita dentin porcelain Group VI : Vintage dentin porcelain Porcelain was built up on the metal plates using a small spoon and then solution matching to each porcelain was added. The six groups are subdivided into a and b. In subgroup a, only excessive solution was absorbed with tissue and in subgroup b, porcelain was condensed sufficiently. When build-up was completed, the shape was measured using the phase-shifting profilometry. After that, specimens were fired in the furnace programed for each porcelain and then their changed shape were measured again. Using the difference between the two above measurements, the ratio of shrinkage was calculated. Obtained results were as follows ; 1. Regardless of condensation, the volume of fired specimens were not different significantly between the two subgroups a and b in the same group. 2. The ratios of shrinkage were significantly higher in the groups porcelain built-up was condensed than in the groups not condensed 3. The ratios of shrinkage were in the range of 36.81-27.19% in the groups porcelain built up was condensed and 44.52-37.54% in the other groups not condensed.

• 대한심미치과학회지
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• 제23권2호
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• pp.70-76
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• 2014

After extraction of tooth, alveolar ridge resorption is inevitable in most cases. Clinicians confront with horizontal and vertical resorption of alveolar bone. Without massive amount of bone and soft tissue graft, dental implant will be placed apically to gain stability. In those cases, not only white esthetic part, but also pink esthetic part should be restored with pink porcelain. The margin of prosthesis should be located apically to reproduce natural look with adjacent teeth. However, when the margin is located apically, it is always hard to remove remaining cement, thus complications may arise. In this report, a novel design of implant prosthesis is introduced to solve those issues. The novel design is consisted of zirconia framework with pink porcelain and separate crowns on top of the framework. It eliminates the possibility of cement remnants by bringing the crown margin coronally. Pink esthetic part is incorporated in abutment part instead of crown part and the screw hole is covered with separate crowns.

• 대한심미치과학회지
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• 제11권2호
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• pp.33-36
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• 2002

As patients have concerned the esthetics of dental restorations, the porcelain fused to metal restorations have gain their popularity due to their strength and esthetic appearance for many years. However, metal collar in subgingival level of porcelain fused to metal restoration often causes black shadows. Inadequately positioned metal collar causes plaque depositions, gingival inflammations, black shadows, and discolorations of margin area. Those problems can be avoided by a clear finishing line, well-fabricated provisional restorations with precise margin and fine polishing, collarless porcelain fused to metal restoration, and all ceramic restoration. In this case report, collarless porcelain fused to metal restoration was used to treat cervical discoloration from old restorations.

• 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.