• Journal of Conservation Science
• /
• v.25 no.3
• /
• pp.273-282
• /
• 2009

As a result of investigating research papers concerning the metal bound rim decoration on four pieces of 'Bowl, white porcelain with impressed floral design and sliver bound rim' and one piece of 'Bowl, white porcelain with sliver bound rim' from among the Jingdezhen white porcelain, which are Sinan remains that are kept in a National museum of Korea. It was found that the material of the bound rim was not silver but tin, and lacquer was used as glue. Based on such a scientific analysis, this study conducted a reproduction test of the manufacturing technique and the bonding method of the metal bound rim attached to the upper tip of the china ware. As a way of reproducing the bound rim, the study was able to discover the best method in terms of the avoidance of loss of materials and the workability out of various cutting methods for tin plates, and it also discovered that the use of lacquer in mixture with soil showed a better workability than the use only of a lacquer ingredient in a test of the bonding method of a metal bound rim using lacquer. Also, in the test of a drying method, a bonding method after drying within a short time at a relatively high temperature was found to be more effective than the drying method after humidifying at a normal temperature, which is used in traditional lacquer ware preservation treatment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.05c
• /
• pp.140-142
• /
• 2001

In this study mechanical for stress according to Pin type of high voltage suspension type insulator. R-shaped metal pin. and a tapered metal pin having a tensile pin having a tensile strength of more than the breaking strength of insulating body are provided in porcelain insulating bodies, and a suspension insulator according to the present invention, a test for determining the tensile strength of the insulating body was made and the results. These insulators are designed and produced by using the computer analysis of mechanical and electrical stresses together with the technical know-how accumulated from long year of study into every respect of insulators.

• Journal of Technologic Dentistry
• /
• v.39 no.2
• /
• pp.101-107
• /
• 2017

Purpose: The purpose of this study was to compare the shear bond strength of the metal-heat pressed glass ceramic bilayer structure. Methods: Metal framework specimens were prepared and surface is spreaded opaque(IPS InLine system opaque, IvoclarVivadent, Liechtenstein). There were 10 specimens for each bilayer dental ceramic group. The first group was porcelain fused metal, Press on metal IPS Inline press group, and press on metal HASS prototype group. Specimens measured for the shear bond strength on Schwickerath test by Instron universal testing machine(Instron3345, Instron Corp., USA). Mean average bond strength values of each specimen group were analyzed using a one-way ANOVA analysis of variance Saphiro-wilk's test. Statistical analysis were performed using IBM SPSS 23.0(IBM Co., Armonk, USA) Results: $RMS{\pm}SD$ The highest mean average HASS POM showed a bond strength value ($47.55{\pm}12.80Mpa$). The lowest mean average values Porcelain fused metal ($33.30{\pm}2.00Mpa$). Independent t-test was conduct to analysis the significant difference (p<0.05) (Table 3). Conclusion: Three kinds of Metal/ glass bilayer dental ceramics bond strength were clinical acceptability. Especially, as lithium disilicate containing represents higher bond strength.

• The Journal of Korean Academy of Prosthodontics
• /
• v.39 no.1
• /
• pp.14-24
• /
• 2001

The purpose of this study was to compare the fracture strengths and the fracture patterns of several hybrid-ceramic crowns and metal-ceramic crown. Ten crowns were constructed for each group according to the manufacturer's instruction. Removable template of silicone rubber impression material was used for standardization of each crowns. Each crown was cemented on a metal die with hybrid glass ionomer cement. All crowns cemented were stored in distilled water, $36^{\circ}C$ for 24 hours prior to loading in an universal testing machine. The load was directed at 130 degrees the long axis of metal die. The fracture strengths were measured and the fracture patterns were observed. The following results were obtained from this study 1. The mean fracture strengths of $Artglass^{(R)}$, $Sculpture^{(R)}$ and $Targis^{(R)}$ were $57.5{\pm}9.5Kgf,\;62.7{\pm}12.2Kgf$ and $60.2{\pm}10.1Kgf$ respectively. There was no significant difference among each hybrid ceramic crown group. 2. The toad required to fracture hybrid-ceramic crowns was significantly smaller than metal-ceramic crowns($131.7{\pm}22.0Kgf$). 3. In the metal-ceramic crowns, labial porcelain detached partially from porcelain-metal junction of proximal side by load. 4. Hybrid-ceramic crowns showed a simple fracture pattern that fracture line began at the loading area and extended through proximal surface, perpendicular to the margin. The crown was separated into two parts of labial side and lingual side. Above results revealed that three kinds of the hybrid-ceramic crowns used in this study must have careful application in clinical use since the strength of hybrid-ceramic crown was lower(about 1/2) than that of metal-ceramic crown.

• The Journal of Korean Academy of Prosthodontics
• /
• v.48 no.4
• /
• pp.273-279
• /
• 2010

Purpose: The purpose of this in vitro study was to compare the marginal adaptation of a ceramic-pressed-to-metal restoration with traditional metal-ceramic restoration. Materials and methods: Duplicating the prepared resin tooth, 20 metal dies were fabricated. Twenty metal copings of 2 groups which were metal ceramic restoration and pressed to metal restoration were fabricated. The marginal opening of each coping was measured with Microscope (BX 60M-36E $41D^{(R)}$: Olympus, Japan). After porcelain build-up, the marginal opening of metal ceramic restoration and pressed to metal restoration ($PoM^{(R)}$: Ivoclar vivadent., Liechtenstein) were also evaluated in the same method. The measurements were analyzed using Wilcoxon Signed Ranks test and Mann-Whitney U test. Results: Within the limits of this study, the results were as follows. 1. Metal-ceramic restorations in coping state ($64.93{\pm}12.48\;{\mu}m$) in compared with Metal ceramic restorations after porcelain build-up ($63.43{\pm}12.86\;{\mu}m$) had no significant difference in marginal adaptation. 2. Pressed-metal-ceramic restorations in coping state ($50.00{\pm}12.28\;{\mu}m$) in compared with Pressed metal ceramic restorations after porcelain build-up ($56.72{\pm}13.80\;{\mu}m$) had no significant difference in marginal adaptation. 3. Metal-ceramic restorations in compared Pressed-metal-ceramic restorations had no significant difference in marginal adaptation. Conclusion: Pressed-metal-ceramic restorations have the advantage of being technically less change through using of the lost-wax technique and this allows for the convenience of a full-contour ceramic wax-up as opposed to the more technique-sensitive layering method. Pressed-metal-ceramic restorations may be considered in clinic on the basis of the result of this study and the advantage of this system.

• The Journal of Advanced Prosthodontics
• /
• v.3 no.4
• /
• pp.196-203
• /
• 2011

PURPOSE. This study evaluated marginal fit of glass infiltrated alumina cores fabricated using two techniques and their marginal stability after firing cycles of veneering porcelain. MATERIALS AND METHODS. Fifteen standardized all-ceramic crowns were fabricated on a metal die using each technique: slip cast technique of VITA In-Ceram sprint Alumina (Group A as control) and plastic foil matrix technique of Turkom-Cera fused alumina core system (Group B). Copings were compared between groups and within groups at coping stage and after firing each layer of veneering porcelain. A device was used to standardize seating of copings on the metal die and positioning of the specimens under the microscope after each stage of fabrication. The specimens were not cemented and marginal gap was measured using an image analyzing software (Imagepro Express) on the photographs captured under an optical microscope. Two tailed unpaired 't test' was used to compare marginal gaps in two groups and one way ANOVA was used to analyze marginal distortion within each group at 95% confidence interval. RESULTS. The marginal gap was smaller at the coping stage in group B ($60+30{\mu}M$) than group A ($81+21{\mu}M$) with statistical significance. After firing of veneering porcelain the difference was insignificant. At the final stage, both groups exhibited lower mean marginal gaps than at the initial coping stage with the difference of $11.75{\mu}M$ for group A and $11.94{\mu}M$ for group B, but it was statistically insignificant due to high value of standard deviation. CONCLUSION. Within the limitations of this study, it was concluded that both techniques produced copings with comparable and acceptable marginal fit and marginal stability on firing veneering porcelain.

• The Journal of Korean Academy of Prosthodontics
• /
• v.24 no.1
• /
• pp.177-189
• /
• 1986

To investigate the bond strength of etched porcelain, porcelain specimens were etched by 5% hydrofluoric acid during the time of 2.5 min., 5 min., 7.5 min., and 10 min. at $23^{\circ}C$ and observed by SEM. Also, electrolytically etched metal was observed by SEM. Etched porcelain specimens were treated or were not treated with Silane coupling agent and bonded to etched metals with Comspan and Panavia. The bonded specimens were stored in water at $37^{\circ}C$. 24 hours after bonding, the bond strengths were measured. There were four groups of 25 specimens each. Group 1 was bonded with Panavia. Group 2 was bonded with Panavia after treated with Silane coupling agent. Group 3 was bonded with Comspan, Group 4 was bonded with Comspan after treated with Silane coupling agent. The results were as follows: 1. he etched porcelains were obviously observed by SEM. 2. The dendritic arms were observed in etched metal by SEM. 3. The bond strength in relation to the increase of etching time increased and an analysis of variance shows significantly different at the 0.01 level in all groups. 4. The bond strength of Silane coupling agent treated groups were higher than the untreated. 5. The ratios of increase of the bond strengths of Silane coupling agent treated groups in relation to the increase of etching of etching time were lower than the untreated. 6. The bond strength of the groups used Comspan were higher than Panavia.

• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.1529-1531
• /
• 1996

Porcelain suspension insulators have teen used for a long time in distribution line. However, Puncture breakdowns in porcelain insulators caused by weaking cement between metal fitting nad porcelain material. There is little puncture breakdown in Epoxy casting insulator. This paper presents electrical test results for the development of suspension insulator used Cycloaliphatic Epoxy resin. Items of test results are as follow - Power Arc test - Aging test - Impulse flashover voltage tests - Puncture tests et.al.

• Proceedings of the KIEE Conference
• /
• 1995.11a
• /
• pp.411-413
• /
• 1995

Porcelain insulators have been used for the almost all of the suspension insulators in distribution line. However, Puncture breakdowns in porcelain insulators caused by westing cement between metal fitting and porcelain material. There is little puncture breakdown in Epoxy casting insulator. This paper presents a new design technique for the development of suspension insulator used Cycloaliphatic Epoxy resin. The design was performed on the basis of two conditions (weather conditions for the past 30 years and the existing installation conditions of KEPCO) and was proven of its adaptability by FEM method.

• The Journal of Korean Academy of Prosthodontics
• /
• v.17 no.1
• /
• pp.67-72
• /
• 1979