PURPOSE: The aim of this study was to evaluate the effect of metal primers on the bonding of dental alloys and veneer resin. Polyvinylpyrrolidone solution's tarnish effect on bonding strength was also investigated. MATERIALS AND METHODS: Disk-shape metal specimens (diameter 8 mm, thickness 1.5 mm) were made from 3 kinds of alloy (Co-Cr, Ti and Au-Ag-Pd alloy) and divided into 4 groups per each alloy. Half specimens (n=12 per group) in tarnished group were immersed into polyvinylpyrrolidone solution for 24 hours. In Co-Cr and Ti-alloy, Alloy Primer (MDP + VBATDT) and MAC-Bond II (MAC-10) were applied, while Alloy Primer and V-Primer (VBATDT) were applied to Au-Ag-Pd alloys. After surface treatment, veneering composite resin were applied and shear bond strength test were conducted. RESULTS: Alloy Primer showed higher shear bond strength than MAC-Bond II in Co-Cr alloys and Au-Ag-Pd alloy (P<.05). However, in Ti alloy, there was no significant difference between Alloy Primer and MAC-Bond II. Tarnished Co-Cr and Au-Ag-Pd alloy surfaces presented significantly decreased shear bond strength. CONCLUSION: Combined use of MDP and VBATDT were effective in bonding of the resin to Co-Cr and Au-Ag-Pd alloy. Tarnish using polyvinylpyrrolidone solution negatively affected on the bonding of veneer resin to Co-Cr and Au-Ag-Pd alloys.
Alloys ; Dental Alloys* ; Povidone

No abstract available.
Dental Alloys* ; Dental Porcelain*

PURPOSE: The purpose of this study was to evaluate the bond strength of composite resin on the fracture surface of metal-ceramic depending on the repair systems and surface roughening methods. MATERIALS AND METHODS: A total of 30 disk specimens were fabricated, 15 of each were made from feldspathic porcelain and nickel-chromium base metal alloy. Each substrate was divided into three groups according to the repair method: a) application of repair system I (Intraoral Repair Kit) with diamond bur roughening (Group DP and DM), b) application of repair system I with airborne-particle abrasion (Group SP and SM), and c) application of repair system II (CoJet Intraoral Repair System, Group CP and CM). All specimens were thermocycled, and the shear bond strength was measured. The data were analyzed using the Kruskal-Wallis analysis and the Mann-Whitney test with a significance level of 0.05. RESULTS: For the porcelain specimens, group SP showed the highest shear bond strength (25.85 +/- 3.51 MPa) and group DP and CP were not significantly different. In metal specimens, group CM showed superior values of bond strength (13.81 +/- 3.45 MPa) compared to groups DM or SM. CONCLUSION: Airborne-particle abrasion and application of repair system I can be recommended in the case of a fracture localized to the porcelain. If the fracture extends to metal surface, the repair system II is worthy of consideration.
Alloys ; Dental Instruments ; Dental Porcelain*

No abstract available.
Alloys* ; Dental Porcelain*

No abstract available.
Alloys* ; Dental Porcelain*

A study of the shear bond strength between dental porcelain and alloy in Ti depostion effect was conducted by Instron universal testing machine. The obtained result was as follows ; The shear bond strength of Ti-depostion group and acid-etched group were statiscally significantly greater than that of untreated control group (p<0.01)
Alloys* ; Dental Porcelain*

PURPOSE: In this study, we evaluated the bond-strength between a few metal ceramic-alloys and veneered-porcelain and found if the bond strength of metal-ceramic alloy with lower gold content than the presently used gold alloy was high enough. MATERIALS AND METHODS: For this study, after plasticizing porcelain only for gold alloy, metal specimen was fabricated using Ni-Cr alloy and gold alloy with different gold content. Three point flexural test were performed to measure their bond-strength. RESULTS: The bonding strength of Group 1 to porcelain was 40.62 +/- 3.32 MPa, which was the highest (P<.05). In sequence of decreasing value, Group 2 (75%) was 37.47 +/- 1.57 MPa, Group 3 (52%) 35.85 +/- 1.48 MPa, Group 4 (51.5%) 35.04 +/- 1.34 MPa, Group 5 (32%) 33.17 +/- 1.62 MPa, Group 6 (10%) 30.75 +/- 1.21 MPa. Bonding strength of Group 3 and Group 4 to porcelain did not show statistically significant difference with comparison to that of Group 5 (Duncan's test, P>.05), while there was a significant difference between that of Group 2, Group 3 and Group 4 and that of Group 6 (Duncan's test, P<.05). The bonding strength between gold alloy and porcelain increased according to the content of gold. In all experimental groups showed higher value than 25 MPa, which is the least value recommended by ISO 9693. CONCLUSION: In all groups, bonding strength was higher than 25 MPa, which is the least value of ISO9693. Therefore, it is considered that metal gold alloy with low gold content is clinically usable.
Alloys ; Dental Porcelain ; Plastics

OBJECTIVETo study the effect of solid phase transformation on the metal-ceramic compatibility of Co-Cr alloy during firing programs.

METHODS9 foils of Co-Cr and Ni-Cr alloy with the dimension of 25 mmx3 mmx0.5 mm were casted using lost wax technology respectively. Among them, 6 specimens were subjected to metal-ceramic bonding strength test (three point bending method), the ceramic layer of 3 specimens were removed for X-ray diffraction (XRD) analysis. One cylindrical specimen of each alloy was casted for the test of coefficient of thermal expansion, cooling curves were recorded.

RESULTSThe metal-ceramic bonding strength of Ni-Cr, Co-Cr alloy was (49.1 +/- 3.40), (40.9 +/- 2.02) MPa respectively. There was significant difference between the two groups' bonding strength (P = 0.00). The coefficient of thermal expansion in the 20-500 degrees C interval of Ni-Cr and Co-Cr alloy was 13.9 x 10(-6), 13.8 x 10(-6) x K(-1) respectively. XRD analysis indicated that the microstructure of Ni-Cr alloy was austenite. While Co-Cr alloy was constituted by fcc phase, hcp phase and sigma phase.

CONCLUSIONDuring the cooling procedure, the transformation of fcc phase to hcp phase and segregation of needle-like sigma phase intensify the linear contraction speed of Co-Cr alloy, which decreases the metal-ceramic adaptability.

In restorative treatment using fixed dental prostheses, dentists should select appropriate restoration material among various types of dental materials. The strength, marginal fit, esthetics, wear resistance, biocompatibility, and cost are important factors in the choice of restoration materials. The present case showed a surface stain on a monolithic zirconia restoration that was due to wear between the monolithic zirconia restoration and the base metal alloy restoration. This phenomenon was confirmed by surface roughness measurement and electron probe micro-analysis.
Alloys ; Dental Alloys ; Dental Materials ; Dental Prosthesis ; Dentists ; Esthetics ; Humans

PURPOSE: The porcelain fused to gold has been widely used as a restoration both with the natural esthetics of the porcelain and durability and marginal fit of metal casting. However, recently, due to the continuous rise in the price of gold, an interest towards materials to replace gold alloy is getting higher. This study compared the bond strength of porcelain to millingable palladium-silver (Pd-Ag) alloy, with that of 3 conventionally used metal-ceramic alloys. MATERIALS AND METHODS: Four types of metal-ceramic alloys, castable nonprecious nickel-chrome alloy, castable precious metal alloys containing 83% and 32% of gold, and millingable Pd-Ag alloy were used to make metal specimens (n=40). And porcelain was applied on the center area of metal specimen. Three-point bending test was performed with universal testing machine. The bond strength data were analyzed with a one-way ANOVA and post hoc Scheffe's tests (alpha=.05). RESULTS: The 3-point bending test showed the strongest (40.42 +/- 5.72 MPa) metal-ceramic bond in the nonprecious Ni-Cr alloy, followed by millingable Pd-Ag alloy (37.71 +/- 2.46 MPa), precious metal alloy containing 83% of gold (35.89 +/- 1.93 MPa), and precious metal alloy containing 32% of gold (34.59 +/- 2.63 MPa). Nonprecious Ni-Cr alloy and precious metal alloy containing 32% of gold showed significant difference (P<.05). CONCLUSION: The type of metal-ceramic alloys affects the bond strength of porcelain. Every metal-ceramic alloy used in this study showed clinically applicable bond strength with porcelain (25 MPa).
Alloys* ; Dental Porcelain* ; Esthetics ; Metal Ceramic Alloys