• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.182-190
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• 2007

Statement of problem: Titanium has many advantages of high biocompatibility, physical properties, low-weight, low price and radiolucency, but it is incompatible with conventional dental porcelain due to titanium's oxidative nature. Many previous studies have shown that they used the method of sandblast for surface treatment prior to porcelain application, the researches are processing about the method of acid etching or surface coating. Purpose: The purpose of this research is to study the effect on bond strength of surface roughness between titanium and porcelain with the same surface topography. Material and method: In this study, we evaluated the bond strength by using 3-point bending test based on ISO 9693 after classified 8 groups - group P : polished with #1200 grit SiC paper, group S10 : $1.0{\mu}m$ surface roughness with sandblasting, group S15 : $1.5{\mu}m$ surface roughness with sandblasting, group S20 : $2.0{\mu}m$ surface roughness with sandblasting, group S25 : $2.5{\mu}m$ surface roughness with sandblasting, group S30 : $3.0{\mu}m$ surface roughness with sandblasting, group S35 : $3.5{\mu}m$ surface roughness with sandblasting, group E : $1.0{\mu}m$ surface roughness with HCl etching. Results: Within the confines of our research, the following results can be deduced. 1. In the results of 3-point bending test, the bond strength of sandblasting group showed significant differences from one of polishing group, acid etching group(P<.05). 2. The bond strength of sandblasting groups did not show significant differences. 3. After surface treatments, the group treated with sandblasting showed irregular aspect formed many undercuts, in the SEM photographs. The bond strength of sandblasting group was higher than 25 MPa, the requirement of ISO 9693. Conclusion: In above results, bond strength of titanium and low-fusing porcelain is influenced more to surface aspect than surface roughness. And titanium has clinically acceptable bond strength below surface roughness of $3.5{\mu}m$.

• Journal of Technologic Dentistry
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• v.31 no.3
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• pp.27-34
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• 2009

This study compared and analyzed changes to the mechanical characteristics to nonprecious metal alloy for porcelain fused to metal crowns when it's repetitively used without the addition of new alloy. Metal samples were made with the Verabond V nonprecious metal alloy. Those samples to measure tensile and yield strength were made in the standardized design(ISO 22674), those to measure bond strength in the $25mm{\times}3mm{\times}0.5mm$ format, and those to measure hardness in the $10mm{\times}10mm{\times}1mm$ format. A ceramic to measure bond strength was made at the center of the metal sample in the length of $8{\ss}{\AE}$ by using Noritaker Super Porcelain EX-3. Ten samples were prepared for one, three and five repetitions of casting each. The test results were as follows: 1. The more casting was repeated, the more significantly tensile strength dropped. 2. The more casting was repeated, the more significantly yield strength dropped. 3. Repetitive casting didn't cause significant changes to bond strength. 4. The Vickers hardness significantly fell with increasing repetitions of casting. There were no changes to bond strength observed with the increasing number of repeating casting. But tensile strength, yield strength, and Vickers hardness decreased. Those results indicate that repeated casting can affect durability and that careful attention should be paid by avoiding repetitive use or excessive increase of uses when no new alloy is added.

• The Journal of Korean Academy of Prosthodontics
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• v.19 no.1
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• pp.61-73
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• 1981

The effects of the opaque porcelain firing temperature, the bonding agent and the degassing prior to the opaque firing On the bond strength were investigated by means of the tensile shear stIe$. The diffusional behaviours at the interface of the porcelain and the alloy, and .the microstructures of the ceramic and metal composite were studied for understanding the bonding mechanism. The results obtained in this experiment were summarizd as follow; 1. With no application of bonding agent, the tensile shear strength of the specimen firing at $1840^{\circ}F$ was higher than that of the specimen firing at $1760^{\circ}F$. 2. The highest bond strength was obtained by application of bonding agent without degassing prior to the opaque firing. 3. Application of bonding agent after the degassing showed the lowest bond strength. 4. The greater number of pores were observed at the firing temperature of $1840^{\circ}F$ than that of $1760^{\circ}F$ in the porcelain and the interface respectively.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.4
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• pp.461-471
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• 2000

This study evaluated the effect of degassing on the ceramic bond strength of two Ni-Cr alloys under varying holding time at the upper limit temperature and atmospheric conditions. Metal specimens were divided into 5 groups for each alloy according to degassing conditions prior to porcelain application no degassing, degassing under vacuum without hold, degassing under vacuum with hold for 5 min. and 10 min. respectively at the upper limit temperature and degassing in air. Total number of metal ceramic specimens was eighty and each group had eight specimens. The ceramic bond strength was measured by four-point flexural test using Instron and the fractured surface was examined under SEM. The results obtained were as follows. 1. Degassing in air improved the ceramic bond strength of Ni-Cr alloys. 2. In degassing under vacuum, hold at the upper limit temperature was advantageous to the ceramic bonding of Ni-Cr alloys. 3. After ceramic metal bond test, metal surfaces were partially covered with the thin porcelain layer, and the cohesive failures in porcelain were predominant in groups showing higher ceramic bond strength.

• Journal of Technologic Dentistry
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• v.39 no.3
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• pp.153-159
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• 2017

Purpose: In this study, a corresponding porcelain coating material was applied to dental Co-Cr metal among PFM. Methods: The bonding strength of the fired specimens was measured by a three-point flexural rigidity test. SEM/EDS was used to observe the surface component of specimens. Results: First, All groups were higher than the minimum bonding strength of 25 MPa specified in ISO 9693 for dental metal-ceramics specimens. Second, The bonding strength of control group(WO) is 44.64 MPa. Experimental group DM was 35.45 MPa and DP was 31.82 MPa(P<0.05). Tukey's HSD tests results have shown that the bonding strength in control group(WO) is higher than that of experimental group(DM, DP). Third, In the case of metal - porcelain bonding strength, the application of opaque porcelain and firing were higher than those of the group treated with degassing process. Conclusion: The bonding strength was higher when the powder opaque porcelain was applied than the paste opaque porcelain.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.3
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• pp.33-41
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• 1991

Cermic has been widely used because of its excellent esthetics and strength. The recently introduced castable ceramic system is regarded as the more esthetic and biocompatible restorative material. The purpose of this study was to compare the shear bond strength of Dicer & G-Cera porcelain laminate veneer according to the type of cement and surface treatment and to observe the surface of bonding failure with SEM. Total forty disks(3.5mm $diam.\times2.0mm$ thickness) were prepared. Forty extracted human maxillary central incisor teeth were stored in saline solution. Ten teeth were bonded to Dicer specimen with Dicer ZPC cement and ten teeth were bonded with Dicer resin cement. Ten silicoated G-Cera specimen and ten non-silicoated G-Cera specimen were bonded to teeth with G-Cera resin cement. Bonded units were mounted in a plastic tube with hard stone and stored in a humidor at $37^{\circ}C$ for 24 hours. Shear bond strength was measured by Instron Universal Testing Machine (Model 1125) and all the specimen were observed with SEM(JEOL, JSM-T2000)and modes of failure were recorded. The obtained results were as follows: 1. The mean shear bond strength of Dicer bonded with Dicer resin cement was 11.62 MPa and that bonded with Dicor ZPC cement was 0.88 MPa : Shear bond strength of Dicer bonded with Dicer resin cement was significantly increased(P<0.05). 2. The mean shear bond strength of silicoated G-Cera was 13.10 MPa and that of non silicoated G-Cera was 10.93 MPa : Shear bond strength of silicoated G-Cera was not significantly increased (P>0.05). 3. Shear bond strength of Dicer and G-Cera porcelain laminate veneer was not significantly different (P>0.05). 4. In observation of bond failure with SEM, Dicer bonded with Dicer ZPC cement exhibited adhesive failure. Dicer bonded with Dicer resin cement and silicoated and non silicoated G-Cera exhibited cohesive failure.

• Journal of Technologic Dentistry
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• v.11 no.1
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• pp.103-109
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• 1989

Bond strength between alloy and ceramic plays an important role in deciding the quaring the processing of metalceramic restorations. Now the author had an experiment on the measurement of bond strength differences accoding to the contents of recast alloy used during the processing of metal-ceramic restorations. In the experiment, Anusavice's Planar Interface Shear Bond Test was employed to determine the bond strength. Total 25 specimens were divided as 5 groups, that is, 5 specimens in a group respections : Group I (new alloy 100%) Group II (new 75%$\cdot$recast 25%), Group III (new 50%$\cdot$recast 50%), Group IV (new 25%$\cdot$recast 75%), Group V(recast 100%). All specimens examined micropically and respective strength values of the group specimens were checked simultaneously. The results were as follows, 1. In the analtsis of variance the result showed the significant differences of 1%(P<0.01) among the each group classifid according to the recast contents. 2. When the interfaces of specimens were examined with an electron microscope, the air bubble were evenly occurred in all the specimens, and the occurrence frequencies and the sizes of air bubble were different between Group I and Group III, especially marked different Group I and Croup V. 3. In respective verification of each group through T-test, between Group I and Group II, between Group I and Group III did not show significant differences. 4. There was significant difference between Group I and Group IV, between Group I and Group V as 1%(P<0.01). 5. In the Shear Bond Test of all the groups, Croup V showed the lowest value. Explanatoion of Figures Fig 1. Main fracture type of metal-porcelain interlace showed in group I, II, III from shear Bond Test resets. Fig 2. Main fracture type of metal-porcelain interface showed In group Ⅳ, Ⅴ form shear Bond Test resets. Air bubble and their size appeared around interface of metal-porcelain. Fig 3. Group I, Fig 4. Group II Fig 5. Group III, Fig 6. Group IV, Fig 7. Group V.

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

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.2
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• pp.195-209
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• 1991

When the porcelain fused to metal restorations were fractured at the metal interface, various techniques and materials for intraoral porcelain repair have been suggested. The purpose of this study was to investigate the effect of metal surface treatment method and water storage on the shear bond strength of four porcelain repair systems. : Clearfil(Kuraray), All-bond(Bisco), Superbond C & B(Sun Medical), Panavia OP(Kuraray). After the metal surfaces of the specimens were sandblasted by aluminum oxide or roughened by diamond point, they were stored in double deionized water(24 Hr., $37^{\circ}C$) and thermocycling was performed(24 Hr., 1024 cycles), and again half of specimes were stored in water bath(2 Months, $37^{\circ}C$). Mean shear bond strength and mode of failure were recorded. The results of this study were obtained as follows : 1. Differences were observed between the sandblasted and diamond - treated specimens in Clearfil, All-bond, and Superbond. No statistically significant differences were observed in Panavia. 2. The 2-month storage time significantly affected the bond strength of All-bond and Superbond. No statistically significant differences were observed in Clearfil and Panavia. 3. The failures were observed at the interface between opaque resin and the metal in Clearfil and All-bond. 4. The failures were observed at the interface between opaque resin and veneered resin in Panavia. The failures were observed at the interface between opaque resin and veneered resin in Superbond, but 40% of them were fractured at the interface between the metal and opaque resin after 2-month storage time.

• The Journal of Advanced Prosthodontics
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• v.7 no.1
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• pp.69-75
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• 2015

PURPOSE. To compare the shear bond strength of various veneering materials to grade II commercially pure titanium (CP-Ti). MATERIALS AND METHODS. Thirty specimens of CP-Ti disc with 9 mm diameter and 10 mm height were divided into three experimental groups. Each group was bonded to heat-polymerized acrylic resin (Lucitone 199), porcelain (Triceram), and indirect composite (Sinfony) with 7 mm diameter and 2 mm height. For the control group (n=10), Lucitone 199 were applied on type IV gold alloy castings. All samples were thermocycled for 5000 cycles in $5-55^{\circ}C$ water. The maximum shear bond strength (MPa) was measured with a Universal Testing Machine. After the shear bond strength test, the failure mode was assessed with an optic microscope and a scanning electron microscope. Statistical analysis was carried out with a Kruskal-Wallis Test and Mann-Whitney Test. RESULTS. The mean shear bond strength and standard deviations for experimental groups were as follows: Ti-Lucitone 199 ($12.11{\pm}4.44$ MPa); Ti-Triceram ($11.09{\pm}1.66$ MPa); Ti-Sinfony ($4.32{\pm}0.64$ MPa). All of these experimental groups showed lower shear bond strength than the control group ($16.14{\pm}1.89$ MPa). However, there was no statistically significant difference between the Ti-Lucitone 199 group and the control group, and the Ti-Lucitone 199 group and the Ti-Triceram group. Most of the failure patterns in all experimental groups were adhesive failures. CONCLUSION. The shear bond strength of veneering materials such as heat-polymerized acrylic resin, porcelain, and indirect composite to CP-Ti was compatible to that of heatpolymerized acrylic resin to cast gold alloy.