• 대한치과보철학회지
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• 제45권2호
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• pp.203-215
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• 2007

Statement of problem: Titanium and its alloy, with their excellent bio-compatibility and above average resistance to corrosion, have been widely used in the field of dentistry. However, the excessive oxidization of titanium which occurs during the process of firing on porcelain makes the bonding of titanium and porcelain more difficult than that of the conventional metal-porcelain bonding. To solve this problem related to titanium-porcelain bonding, several methods which modify the surfaces, coat the surfaces of titanium with various pure metals and ceramics, to enable the porcelain adhesive by limiting the diffusion of oxygen and forming the adhesive oxides surfaces, have been investigated. Purpose: The purpose of this study was to know whether the titanium-porcelain bonding strength could be enhanced by treating the titanium surface with gold and TiN followed by fabrication of clinically applicable porcelain-fused-to-titanium crown Material and method: The porcelain-fused-to-titanium crown was fabricated after sandblasting the surface of the casting titanium coping with $Al_2O_3$ and treating the surface with gold and TiN coating followed by condensation and firing of ultra-low fusing porcelain. To compare with porcelain-fused-to-titanium crowns, porcelain-fused-to-gold crowns were fabricated and used as control groups. The bonding strengths of porcelain-fused-to-gold crowns and porcelain-fused-totitanium crowns were set for comparison when the porcelain was fractured on purpose to get the experimental value of fracture strength. Then, the surface were examined by SEM and each fracturing pattern were compared with each other Result:Those results are as follows. 1. The highest value of fracture strength of porcelain-fused-to-titanium crowns was in the order of group with gold coating, group with TiN coating, group with $Al_2O_3$ sandblasting. No statistically significant difference was found among the three (P>.05). 2. The porcelain-fused-to-gold crowns showed the highest value in bonding strength. The bonding strength of crowns porcelain-fused-to-titanium crowns of rest groups showed bonding strength reaching only 85%-94% of that of PFG, though simple comparision seemed unacceptable due to the difference in materials used. 3. The fracturing patterns between metal and porcelain showed mixed type of failure behavior including cohesive failure and adhesive failure as a similar patterns by examination with the naked eye and SEM. But porcelain-fused-to-gold crowns showed high incidence of adhesive failure and porcelain-fused-to-titanium crowns showed high incidence of cohesive failure. Conclusion: Above results proved that when fabricating porcelain-fused-to-titanium crowns, treating casting titanium surface with gold or TiN was able to enhance the bonding strength between titanium and porcelain. Mean value of masticatory force was found to showed clinically acceptable values in porcelain bonding strength in all three groups. However, more experimental studies and evaluations should be done in order to get better porcelain bonding strength and various surface coating methods that can be applied on titanium surface with ease.

• 대한치과보철학회지
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• 제45권4호
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• pp.419-430
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• 2007

Purpose: This in vitro study evaluated shear bond strengths of surface treatment porcelains with four porcelain repair systems simulating intraoral bonding of composite resin to feldspathic porcelain or pressable porcelain. Material and methods: Eighty Porcelain disks were prepared. Group A: forty disk specimens were fabricated with Feldspathic Porcelain($Omega^{(R)}900$, Vident, Menlo Park, CA, USA). Group B: forty disk specimens were fabricated with Pressable Porcelain(IPS Empress 2 ingot, Ivoclar-Vivadent, Schaan, Liechtenstein, Germany). Each groups was divided into 4 subgroups and composite resin cylinders were bonded to specimen with one of the following four systems: Clearfil Porcelain Bond(L. Morita, Tustin, CA, USA), Ulradent Porcelain Etch. (Ultradent, Salt Lake City UT, USA), Porcelain Liner-M(Sun Medical Co., Kyoto, Japan), Cimara Kit(Voco, Germany). After surface conditioning with one of the four porcelain repair systems substrate surfaces of the specimen were examined microscopically(SEM). Shear bond strengths of specimens for each subgroup were determined with a universal testing machine (5mm/min crosshead speed) after storing them in distilled water at $37{\pm}1^{\circ}C$ for 24 hours. Stress at failure was measured in $MP_a$, and mode of failure was recorded. Differences among four repair systems were analyzed with two way ANOVA and Duncan test at the 95% significance level. Results: In the scanning electron photomicrograph of the treated porcelain surface, hydrofluoric acid etched group appeared the highest roughness. The shear bond strength of the phosphoric acid etched group was not significantly(p>0.05) different between feldspathic porcelain and pressable porcelain. But in no treatment and roughened with a bur group, the shear bond strength of the feldspathic porcelain was significantly higher than that of the pressable porcelain. In hydrofluoric acid etched group, the shear bond strength of the pressable porcelain was significantly higher(p<0.05). Conclusion: 1. Treatment groups showed significantly greater shear bond strengths than no treatment group(p<0.05). 2. Group with more roughened porcelain surface did not always show higher shear bond strengths. 3. In phosphoric acid etched group, there was no significant difference in shear bond strength between feldspathic porcelain and pressable porcelain(p>0.05). However in the other groups, there were significant differences in shear bond strengths between feldspathic porcelain and pressable porcelain(p<0.05).

• 대한치과기공학회지
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• 제21권1호
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• pp.15-26
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• 1999

This study was carried out by observing to composition of oxide on the surface of dental porcelain low gold alloy with various Indium additions according to the degassing and analysing the change composition of additional elements In on diffusion behaviors of Porcelain-matal surface. The specimens used were Au-Pd-Ag alloys by small indium addition. These specimens were treated for 10min at $1000^{\circ}C$ in vacuum condition. To investigate the microsturcture of oxidized alloy surface, SEM and EDAX were used, and EPMA were used to investigate the diffusion behaviors of porcelain-metal surface. X-ray diffraction were used to observe the morphological changes in the oxidation zone. The results of this study were obtained as follows ; 1) The hardness of alloy increased with increasing amount of In addition. 2) The formation of oxidation increased with increasing In content after heat treatment. 3) Diffusion of indium elements increased with increasing In content in metal-porcelain surface after firing. 4) The oxidations of alloy surface were mainly $In_2O_3$.

• 한국세라믹학회지
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• 제50권2호
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• pp.127-133
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• 2013

Porcelain with high thermal shock resistance was successfully fabricated by a lithium solution infiltration method with a lithium hydroxide solution. Lithium hydroxide solutions having various lithium concentrations were infiltrated into pre-sintered porcelain bodies. The porcelain sample infiltrated by the 9 wt% lithium solution and heat treated at $1250^{\circ}C$ for 1 h showed a low thermal expansion coefficient of $1.0{\times}10^{-6}/^{\circ}C$ with excellent thermal shock resistance. The highly thermally resistant porcelain had a well-developed ${\beta}$-spodumene phase with the general phases observed in porcelain. Furthermore, the porcelain showed a denser structure of $2.41g/cm^3$ sintering density and excellent whiteness in comparison with commercial thermally resistible porcelains. The lithium hydroxide in the samples readily reacted with moisture, and liquid phase reactants were formed during the fabrication process. In the case of an excess amount of lithium in the sample body, the lithium reactants were forced to the surface and re-crystallized at the surface, leaving large pores beneath the surface. These phenomena resulted in an irregular structure in the surface area and led to cracking in samples subjected to a thermal shock test.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.199-202
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• 1999

The paper deals with the surface discharge characteristics for porcelain suspension insulators. The micro-crystals were crystallized on the surface of glace coated on the porcelain These micro-crystals may affect the electrical Properties such as flashover voltage. However. not much research have been conducted. In this study. we correlated the surface discharge characteristics to the microstructures. It was confirmed that the micro-crystals on the glaze initiated the flashover when the surface was wetted and/or contaminated.

• 대한치과보철학회지
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• 제28권2호
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• pp.147-163
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• 1990

Although dental porcelain demonstrates lasting esthetic results, it suffers from inherent brittle fractures. Various techniques and materials for intraoral porcelain repair has been suggested. This study investigated the in vitro shear strength of three porcelain repair systems according to aspects of the porcelain fractures. The purpose of this study was to evaluate the shear bond strength of three porcelain repair systems(All-bond, Clearfil, Scotchprime) according to fractured surface of porcelain - fused - to - metal restorations. For this study specimens were divided into five groups : group 1 represented fracture occurred at body porcelain layer, group 2 represented fracture occurred at opaque porcelain layer, group 3 represented fracture including 1/3 of metal exposure, group 4 represented fracture including 2/3 of metal exposure, and group 5 represented all metal surface was exposed. Specimens were stored in double deionized water(24Hr, $37^{\circ}C$) and thermocycling was performed(24Hr, 1080cycles), and subjected to a shear force parallel to the repair resin and porcelain interface by use of an University Testing Machine. The results of this study were obtained as follows : 1. In group 1 and 2, bond strength was relatively high, and bond strength showing reducing tendency as exposure of metal was increased. 2. In group 1, bond strength was relatively high, and no significant differences in porcelain repair system. 3. In group 2, 3 and 4, All-bond and Clearfil provided significantly higher bond strength than scotchprime. 4. In group 5, bond strength was the lowest among all groups and especially in case if Scotchprime. 5. Cohesive failure was observed in group 1 and 2, adhesive failure was observed in group 5, and cohesive / adhesive failures were observed in group 3 and 4.

• 대한치과교정학회지
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• 제22권1호
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• pp.43-65
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• 1992

Bonding orthodontic adhesive resins to glazed porcelain surface is not attainable. The aim of this investigation was to examine, in vitro, the effect of three methods of porcelain surface pretreatment on the shear bond strength of orthodontic adhesives, and to compare the shear strength of orthodontic bracket bonding to porcelain surface by the best results that to human enamel. Porcelain disks ($Ceramco^{(TM)}$ and $Vita^{(TM)}$) baked in the laboratory were roughened by sandpapers, #320, #600, #800, #1000 and #1200, and were pretreated with silane and dried at the various temperatures, room temperature, $50^{\circ}C$, $70^{\circ}C$ and $90^{\circ}C$, and were etched by 3% hydrofluoric acid solution for 1, 3, 5, 7, and 9 minutes, orthodontic adhesives (System $1+^{(TM)}$ and $Unite^{(TM)}$) were applied on them, and shear bond strengths were measured by Instron. The best results of pretreatment of each method were determined by the shear bond strengths. Again, porcelain disks were pretreated by the determined best results and human enamel were etched by 37% hydrofluoric acid solution, orthodontic brackets were bonded on them by the orthodontic adhesives, and the shear bond strengths were measured and compared between them. 1. Roughening porcelain surfaces with coarse sandpaper (#300) showed higher shear bond strength than that with finer sandpapers, but it $(22.44Kgf/cm^2)$ was distinguishably low compared to that from etched human enamel $(144.11Kgf/cm^2)$. 2. There were disparities in shear bond strengths upon the orthodontic resins, which was presumably related to the contents of fillers in orthodontic adhesive resins. Also there were disparities in shear bond strength upon the porcelains which had different composition. 3. Silane enhanced the shear bond strength of orthodontic resins to porcelain surfaces ($25.20Kgf/cm^2$ at $50^{\circ}C$), which was markedly low compared to that from etched human enamel. 4. Etched porcelain surface with 3% hydrofluoric acid solution for 1 to 9 minutes showed no difference in shear bonding strength of orthodontic adhesive resins. Shear bond strength from etched porcelain $(97.43-120.72Kgf/cm^2)$ were as high as clinically available, but low compared to that from etched human enamel. 5. Roughening with #300 sandpaper and etching by 3% hydrofluoric acid followed silane application on porcelain surface showed lower shear bond strength than etched human enamel, but were as high as clinically useful. 6. The results suggest that etching porcelain surface by 3% hydrofluoric acid solution might provide comparatively high shear bond strength as much as clinically favorable.

• 구강회복응용과학지
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• 제19권1호
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• pp.35-41
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• 2003

With the understanding of tooth crown biomechanics and the progress of dentin adhesives, bonded porcelain restorations including a porcelain laminate veneer present an extended spectrum of indications for anterior teeth. Porcelain laminate veneer as a restoration offers the conservative solution that balances the functional and esthetic needs of the anterior dentition. Porcelain's stiffness, its surface characteristics, and the biomechanical strength achieved through bonding to tooth surface enable the restoration of the tooth as a whole supporting occlusal force and masticatory function. Namely, the optical effects inherent in the tooth and the lifelike features of the porcelain make that this restoration approaches the ultimate in esthetic satisfaction for both the dentist and the patient. A 49-year-old female patient with the incisal discoloration of upper central incisors and black triangle between the central incisors was referred to correct her esthetic problems with prosthodontic approach. The patient was satisfied with two porcelain laminate veneers that were made according to prof. Magne and Belser's recommendation.

• 대한치과보철학회지
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• 제19권1호
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• pp.29-37
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• 1981

The bond strengths with ceramco porcelain were compared between precious alloy S, and non-precious alloys V.U. and R. And the changes in bond strengths of non-precious alloys with ceramco porcelain, according to surface preparations by sand blasting, longitudinal grinding, transverse grinding, and high polishing, were studied. The test specimens were prepared by firing porcelain doughnuts on the surface prepared alloy rods, and investing in dental stone. The specimens were subjected to shear loading forces. The conclusions drawn from the investigation are as follows: 1. The bond strengths with ceramco porcelain were higher in the non-precious alloys U and R, than in the precious alloy S. 2. The bond strengths were in descending order for R alloy, U alloy, V alloy, and S alloy. 3. The bond strengths were highest when the R alloy and U alloy were surface prepared by sand blasting. 4. All bond strength values were lowest when the alloy surfaces were prepared by high polishing.

• 대한치과기공학회지
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• 제22권1호
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• pp.39-47
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• 2000

This study is the know the difference bond strength according to painting method of Opaque porcelain. Among Porcelain powder for Porcelain, Noritake powder, Bonding agent 1 class and metal are selected as Base metal alloy. And painting method of Opaque porcelain is divided by 4 groups : PG, WG, NG and DG. Also it is to manufacture 24 sheets of Specimen by 6 each every method and to measure Crack-initiation Strength of Metal-porcelain and it is to observe it by Scanning electron microscope. I come to get a conclusion as follows. 1. As for Debonding strength of every experiment groups, it showed that WS group which executed Wash bake had highest value, 44.25MPa and NG group which used Normal powder had value, 42.11MPa and DG group which used Bonding agent had value, 35.88MPa and PG group which used Paste opaque had value, 35.39MPa. 2. In four painting methods of Opaque porcelain, PG group, WG group, NG group and DG group, there is no significant difference statistically in Crack-initiation Strength. 3. As a result of observing fracture surface with Scanning electron microscope, it was showde that PG group remained a lot of particle of porcelain on the surface of metal than WG group, NG group and DG group.