• 한국세라믹학회지
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• 제19권2호
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• pp.139-144
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• 1982

This study has examined closely on the various foundamental conditions for the fitting in steatite porcelain as a industrial porcelain of superior quality, and as a decorated porcelain. The materials consisting of the Kyul Sung talc, and the sea water magnesia clinker power which was produced from Sam Hwa-Hwa Sung, as major constituents have been used, and also used Hyup Jin kaolin as clay minerals to give them plasticity. First, the mixture was made of corresponding in the theoretical composition of enstatite with Kyul sung talc and sea water magnesia clinker, and kaolin was added in various kinds of 1%, 2.5% 5%, 10%, and 20% by weight of the mixture. Next, the mixture was fired at the various temperatures from 1330 to 145$0^{\circ}C$. After we examined closely the physical properties and microstructures, we achieved the results that noted from this study were listed below. 1. The addition amount of kaolin should generally be from 5% to 10% by weight of the mixture to give mixture plasticity in steatite porcelain, but preferably about 20% to consider the firing temperature. 2. The temperature of the optimum firing range is from 1390 C to 142$0^{\circ}C$. 3. A case, which the $A_2$ composition had been fired at 142$0^{\circ}C$, showed a good effect in the strength, but showed a bad result in the absorption. Therefore, the specimens of $A_4$ the composition has excellent in properties of matters when the composition is fired at 142$0^{\circ}C$. Also, we consider that the specimens of the $A_5$ composition, which is fired at 139$0^{\circ}C$, is suitable for the $MgO-SiO_2$ porcelain bodies with respect to the various properties.

• 대한치과보철학회지
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• 제25권1호
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• pp.95-118
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• 1987

This study was undertaken to observe the elemental transition of Interface depending on different pretreatment methods, the number of filings, the kinds of porcelain powders and the various alloys in ceramo-metal restoration. The materials used in this study were Pors-on $4^{(R)}$ and Ceramco porcelain powder to compare the differences depending on the pretreatement methods and the number of firings. Ceramco porcelain powder and Vita porcelain powder were used to compare the differences of elemental transition depending on the porcelain powders. The $Parasil^{(R)},\;PGV^{(R)}$ and Pors-on $4^{(R)}$ as Pd-Ag alloy were used to compare the difference of elemental transition depending on the various alloys. The pretreatment methods were : no treatment, treatment under vacuum and air, treatment with 50 % hydrofluoric acid and double heat tretament. The number of firings were 3, 5 and 7 repeated firings All specimens were observed by SEM and concentration of elements were analyzed quantitatively with EPMA The results of this study were obtained as follows : 1. In the groups of air-treatment, concentration of Sn were the highest and widest. A high concentration of In were in the groups of vacuum and air treatment. 2. There were no significant differences in concentration of Sn between the group of vacuum, 5 minutes hydrofluoric acid and double heat treatment. (p>0.05) 3. As the period of time of hydrofluoric acid treatment increased, not only were the trace elements reduced but the main components such as Pd and Ag were also reduced. 4. Concentration of Sn and In increased and diffused with repeated firings but 5 repeated and 7 repeated firings groups had no significant differences. (p>0.05) 5. Sn were more concentrated in the group of Ceramco porcelaion powder than Vita porcelain powder. 6. The higher concentration of trace elements in the alloy, the more increasing concentration of Sn and In in the interface.

• The Journal of Advanced Prosthodontics
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• 제6권4호
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• pp.278-284
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• 2014

PURPOSE. There is insufficient data regarding the durability of porcelain laminate veneers bonded to existing composite fillings. The aim of the present study was to evaluate the fracture resistance and microleakage of porcelain laminate veneers bonded to teeth with existing composite fillings. MATERIALS AND METHODS. Thirty maxillary central incisors were divided into three groups (for each group, n=10): intact teeth (NP), teeth with class III composite fillings (C3) and teeth with class IV cavities (C4). Porcelain laminate veneers were made using IPS-Empress ceramic and bonded with Panavia F2 resin cement. The microleakage of all of the specimens was tested before and after cyclic loading ($1{\times}10^6$ cycles, 1.2 Hz). The fracture resistance values (N) were measured using a universal testing machine, and the mode of failure was also examined. The statistical analyses were performed using one-way ANOVA and Tukey post hoc tests (${\alpha}=.05$). RESULTS. There was a significant difference in the mean microleakage of group C4 compared with group NT (P=.013). There was no significant difference in the fracture loads among the groups. CONCLUSION. The microleakage and failure loads of porcelain laminate veneers bonded to intact teeth and teeth with standard class III composite fillings were not significantly different.

• The Journal of Advanced Prosthodontics
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• 제6권4호
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• pp.317-324
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• 2014

PURPOSE. This study was to evaluate the effect of grinding of the inner metal surface during the porcelain try-in stage on metal-porcelain bonding considering the maximum temperature and the vibration of samples. MATERIALS AND METHODS. Ninety-one square prism-shaped ($1{\times}1{\times}1.5mm$) nickel-chrome cast frameworks 0.3 mm thick were prepared. Porcelain was applied on two opposite outer axial surfaces of the frameworks. The grinding was performed from the opposite axial sides of the inner metal surfaces with a low-speed handpiece with two types of burs (diamond, tungsten-carbide) under three grinding forces (3.5 N, 7 N, 14 N) and at two durations (5 seconds, 10 seconds). The shear bond strength (SBS) test was performed with universal testing machine. Statistical analyzes were performed at 5% significance level. RESULTS. The samples subjected to grinding under 3.5 N showed higher SBS values than those exposed to grinding under 7 N and 14 N (P<.05). SBS values of none of the groups differed from those of the control group (P>.05). The types of bur (P=.965) and the duration (P=.679) did not affect the SBS values. On the other hand, type of bur, force applied, and duration of the grinding affected the maximum temperatures of the samples, whereas the maximum vibration was affected only by the type of bur (P<.05). CONCLUSION. Grinding the inner metal surface did not affect the metal-porcelain bond strength. Although the grinding affected the maximum temperature and the vibration values of the samples, these did not influence the bonding strength.

• KIEE International Transactions on Electrophysics and Applications
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• 제5C권1호
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• pp.8-13
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• 2005

In order to analyze the properties of domestically produced 36,000lb porcelain insulators by change of the alumina addition to raw materials, 36000lb ball socket type suspension insulators that were manufactured in 1989, 1995 and 2001 were removed from transmission lines and an experiment was performed. The results indicated that 8 [wt.%] alumina, which influences the mechanical properties and arc resistance properties in the case of insulators that were manufactured in 1989 was contained, and the relative density and the fracture toughness of insulators appeared by 94.2% and 1.4 [MpaㆍM/sup 1/2/], respectively. However, 12 [wt.%] alumina was contained in the case of insulators that were manufactured in 1995, and the relative density and the fracture toughness of insulators appeared preferably lower by 92% and 1.3 [MpaㆍM/sup 1/2/], respectively. The greatest amount of alumina was contained by 17 [wt.%] in the case of insulators that were manufactured in 2001. It was confirmed that the electrical and mechanical characteristics such as the relative density and the fracture toughness appeared remarkably by 96% and 1.7 [Mpaㆍm/sup 1/2/], respectively.

• 대한치과보철학회지
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• 제27권2호
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• pp.79-100
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• 1989

The Purpose of this study was to investigate material differences in stress transmission among various artificial teeth and denture base materials. For this study, a two-dimensional finite element model and a two-dimensional photoelastic model of a mandible with complete denture were made. A resin tooth and a porcelain tooth were used as artificial teeth, and a resin base, a metal lined base, and a soft-liner lined base were used as denture bases. An occlusal load was applied and principal stresses generated in the supporting tissues were compared. To test the impact stress transmission, strain gauge attached to the denture base specimens made of the different materials were made in thick and thin groups. Voltage outputs from hitting the specimen with a steel ball were compared. The results were as follows : 1. In FEM, increasing the mucosal thickness reduced the maximum principal stresses in the supporting tissues, but altering the tooth materials and the base materials induced no difference in the stresses. 2. In photoelastic model study, no difference in fringe order among the specimens were observed, but the thick mucosa group and the soft-liner lined group revealed a more uniform distribution of the load. 3. In strain measuring, the impact force transmission was highest in the soft-liner lined group, and was the lowest in the metal lined group(p<0.01). 4. In the thin group using the resin base, the porcelain tooth showed higher impact stress transmission than the resin tooth(p<0.01), but no difference was observed between them in the thick group. In the soft-liner lined group, the porcelain tooth showed higher impact stress transmission than the resin tooth(p<0.01), but no difference was observed between them in the metal lined group. 5. The thick group showed lower impact stress transmission than the thin group(p<0.01).

• 대한치과재료학회지
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• 제43권4호
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• pp.343-349
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• 2016

This experiment was carried out to examine whether the post-firing heat treatment is effective in increasing the hardness of metal-ceramic alloy of the Pd-Au-Ag-Sn system. Precipitation hardening by holding at $600^{\circ}C$ after simulated complete porcelain firing in a metal-ceramic alloy of the Pd-Au-Ag-Sn system was examined by observing the change in hardness, crystal structure, and microstructure using a hardness test, X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). The hardness of the alloy increased apparently by holding the specimen at $600^{\circ}C$ for 30 min after simulated complete porcelain firing. The formation of fine grain interior precipitates during holding at $600^{\circ}C$ caused the formation of lattice strain in the grain interior, resulting in apparent hardening. The faster cooling rate (stage 0) during simulated complete porcelain firing resulted in more effective precipitation hardening during holding at $600^{\circ}C$. From the above results, an appropriate post-firing heat treatment, such as holding at $600^{\circ}C$ for 30 min after complete porcelain firing may increase the durability of metal-ceramic prostheses composed of Pd-Au-Ag-Sn alloy.

• Transactions on Electrical and Electronic Materials
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• 제10권5호
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• pp.161-164
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• 2009

Forest fire simulation tests were performed with polymer and porcelain insulators at GOCHANG Power Testing Center. These tests consisted of open flames causing a temperature rise of up to $600{\sim}800^{\circ}C$ measured at the insulator surfaces. Mechanical and electrical characteristics such as the specific mechanical load, the low frequency dry flashover voltage and the impulse flashover voltage were analyzed for the polymer insulators before, during and after the simulation tests and then compared to the porcelain insulators. At the end of the fire simulation tests, there was no detrimental deterioration of any of the insulators. All the insulators passed the KEPCO specification criteria. This study showed that the forest fire simulation had no impact on the polymer insulators.

• 한국의류산업학회지
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• 제11권2호
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• pp.242-251
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• 2009

Traditional patterns of Korea vary greatly and have excellent value in terms of artistic merit. Nevertheless because there are not enough the research and development of them, traditional patterns of Korea are not yet recognized in internationally aesthetic value. Therefore the development of designs modernizing traditional patterns of Korea is urgently needed. In this study, I chose Four gracious plants as the subject materials of textile design development. Before everything I examined data of Four gracious plants expressed on Blue and white porcelain. And I chose data that are suitable to express modern image among them. I set my face to develop the textile design of Korean images by adding modern scenes with them. Also, I were trying to make fashion products like muffler and tie by using techniques such as burn out, crayon dying and spray dyeing.

• 대한심미치과학회지
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• 제32권2호
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• pp.46-53
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• 2023

도자기 파절은 금속도재, 전부도재, 지르코니아 수복물의 흔한 문제점이다. 이와 관련되 여러가지 요소들이 제시되는데, 금속의 물성, 금속도재의 금속 코핑의 형태, 가공 방법, 지지형태, 교하벽, 비기능적 습관들이 포함된다. 이 논문에서는 이런 요소들을 조금더 구체적으로 살펴보고자 한다.