A comparison of 3 alloy surface treatments for resin-bonded prostheses

PURPOSE: The most frequent cause of clinical failure of resin-bonded fixed partial dentures is a debonding at the metal-cement interface. The purpose of this in vitro study was to compare the tensile bond strengths of 3 different alloy-surface treatments when cemented to human enamel with a resin cement. MATERIALS AND METHODS: Cylinders of a nickel-chromium-beryllium (Ni-Cr-Be) and a gold-palladium (Au-Pd) alloy were fabricated and assigned to different surface treatment groups as follows: Group 1: Ni-Cr-Be, chemically etched; Group 2: Au-Pd, airborne particle-abraded and tin-plated; and Group 3: Au-Pd, airborne particle-abraded and treated with the Alloy Primer (Kuraray Co, LTD, Osaka, Japan). The cylinders were bonded to the enamel surfaces of extracted, human third molars and stored in normal saline at 37 degrees C for 48 hours. The tensile bond strength of 21 specimens from each group was measured on a Universal Testing Machine (Instron, Canton, MA). Three failed specimens of each group were evaluated using scanning electron microscopy and energy dispersive spectroscopy. RESULTS: Statistically significant differences (p <.05) were found between all 3 treatment groups. The mean tensile bond strengths (+/- the standard error of mean) recorded as follows: Group 1: 10.6 MPa (+/-1.3), Group 2: 0.9 MPa (+/-0.2), and Group 3: 13.4 MPa (+/-1.0). Specimens from groups 1 and 3 revealed a trend towards mixture of cohesive, within the resin cement, and adhesive failures at the metal-cement interface. Group 2 specimens exhibited primarily adhesive failures at the metal-cement interface. CONCLUSIONS: The tensile bond strength of Au-Pd alloy specimens was significantly increased with the Alloy Primer.     

Effect of a new metal primer on the bond strength between a resin cement and two high-noble alloys

STATEMENT OF PROBLEM: With the development of new adhesive resin cements, the question of surface treatment of noble metal castings with primers has become an important issue. PURPOSE: This study compared the tensile bond strength and its durability of a new metal primer (Alloy Primer, Kuraray) to 2 noble metal alloys (Au-Ag-Cu-Pt and Au-Pt-Pd-Ag-In). MATERIAL AND METHODS: Sixty cast disk specimens of each alloy were polished, grit blasted with 50 microm Al(2)O(3), and ultrasonically cleaned in 96% isopropanol. Then, they were either nonprimed or primed only with the Alloy Primer or Alloy Primer combined with ED Primer (Kuraray). Plexiglas tubes filled with self-curing composite resin (Clearfil FII, Kuraray) were bonded to the metal samples with the use of an alignment apparatus and a self-curing luting cement (Panavia 21 Ex). The samples were stored in water, either for 3 days with no thermal cycling or for 150 days with 37,500 thermal cycles. After the different storage conditions, the tensile bond strengths of the specimens were determined. RESULTS: The mean bond strengths increased over storage time for all groups, except for the grit-blasted Au-Pt-Pd-Ag-In group. However, only in the grit-blasted and the primed groups for the Au-Ag-Cu-Pt alloy was this increase significantly different (P<.01). After 150 days of storage, the mean bond strength to Au-Ag-Cu-Pt alloy was 38.8 MPa without priming, whereas it was 40.6 to 40.8 MPa with the use of the primers. After the same time, the mean bond strength to the Au-Pt-Pd-Ag-In alloy was 20.6 MPa without priming, whereas it was 31. 9 to 37.8 MPa with the use of the primers. When comparing the different bonding methods and different storage times for the alloys, the superiority of the usage of both primers in combination was determined. Conclusion. The tested Alloy Primer significantly improved the bond strength of the dental adhesive resin cement (Panavia 21 Ex) to noble alloys. However, this effect depended on the alloy composition and was much greater for the Au-Pt-Pd-Ag-In alloy than for the Au-Ag-Cu-Pt alloy.     

Laboratory evaluation of a metal-priming agent for adhesive bonding.

OBJECTIVE: The purpose of this laboratory study was to determine the bond strength of a base metal alloy to a high-noble alloy and amalgam when a new chemical adhesion promoter was used in conjunction with a resin cement. METHOD AND MATERIALS: Specimens of high-noble alloy and amalgam were prepared in epoxy-filled rings. Base metal cylinders were cast. The ends of the cylinders and the metal bonding substrates were wet ground and air abraded with aluminum oxide. The base metal cylinders were cemented with Panavia 21 resin cement after application of 1 of the following to the high-noble and amalgam metal surfaces: (1) Alloy Primer, (2) ED Primer, (3) Alloy Primer and ED Primer, or (4) tin plating. Bond values were determined after 24 hours' storage and after 3 months' storage and thermocycling. RESULTS: At both 24 hours and 3 months, tin plating yielded the highest bond strengths to a high-noble alloy, but the value for the Alloy Primer groups was not significantly lower. There was no statistically significant difference between the 24-hour and 3-month values within the 4 treatment regimens. CONCLUSION: Treatment of amalgam or high-noble alloy with either tin plating or Alloy Primer before bonding with Panavia 21 resin cement yielded equivalent bond strengths to a base metal alloy. ED Primer was not an effective metal primer. There was no advantage to combining Alloy Primer and ED Primer.     

Use of metal conditioners to improve bond strengths of autopolymerizing denture base resin to cast Ti-6Al-7Nb and Co-Cr

OBJECTIVE: The shear bond strengths of an autopolymerizing denture base resin to cast Ti-6Al-7Nb and Co-Cr alloys using three metal conditioners were investigated. METHODS: Ti-6Al-7Nb alloy and Co-Cr alloy discs were cast. The disc surfaces were air-abraded with 50 microm alumina particles and treated with three metal conditioners (Alloy Primer; Cesead II Opaque Primer; Metal Primer II). An autopolymerizing denture base resin was applied on the discs within a hole punched in a piece of sticky tape and a Teflon ring to define the bonding area. All specimens were immersed in 37 degrees C water for 24 h. Half of the specimens were thermocycled up to 20,000 cycles. The shear bond strengths were determined at a crosshead speed of 1.0 mm/min. RESULTS: Specimens treated with the three metal conditioners had significantly (p<0.05) improved shear bond strengths of the autopolymerizing denture base resin to both Ti-6Al-7Nb and Co-Cr. Although the bond strengths of the bonded Ti-6Al-7Nb specimens were higher than those of the Co-Cr alloy before thermocycling, the decrease in the bond strength of Ti-6Al-7Nb was considerably greater than that of the Co-Cr after thermocycling. CONCLUSION: Significant improvements in bond strength of the autopolymerizing denture base resin to cast Ti-6Al-7Nb alloy and Co-Cr alloy were achieved through the application of Alloy Primer, Cesead II Opaque Primer and Metal Primer II. The bond durability to Ti-6Al-7Nb alloy was inferior to that to Co-Cr.     

Comparative evaluation of thione and phosphate monomers on bonding gold alloy and Ti-6Al-7Nb alloy with tri-n-butylborane initiated resin

This study aimed to evaluate the bonding behaviors of a gold alloy and a titanium-aluminum-niobium (Ti-6Al-7Nb) alloy after priming with three metal conditioners. Cast alloy disks were ground and divided into the following four conditions: (1) unprimed control versus priming with (2) Alloy Primer, (3) Estenia Opaque Primer, or (4) V-Primer. The disks were bonded with tri-n-butylborane (TBB) initiated methacrylic resin, and shear bond strengths were determined both before and after 20,000 times of thermocycling. Alloy Primer and V-Primer--which contained a vinyl-thione monomer--were effective for bonding the Au-Pt-Pd alloy. As for the hydrophobic phosphate monomer contained in Alloy Primer and Estenia Opaque Primer, it was effective for bonding the Ti-6Al-7Nb alloy. Further, when specimens were primed with Alloy Primer that contained both functional monomers, bond strength to Ti-6Al-7Nb alloy was greater than that to Au-Pt-Pd alloy.     

Influence of thermal and mechanical cycling on the flexural strength of ceramics with titanium or gold alloy frameworks.

OBJECTIVES: The aim of this study was to evaluate the effect of thermal and mechanical cycling alone or in combination, on the flexural strength of ceramic and metallic frameworks cast in gold alloy or titanium. METHODS: Metallic frameworks (25 mm x 3 mm x 0.5 mm) (N=96) cast in gold alloy or commercial pure titanium (Ti cp) were obtained using acrylic templates. They were airborne particle-abraded with 150 microm aluminum oxide at the central area of the frameworks (8 mm x 3 mm). Bonding agent and opaque were applied on the particle-abraded surfaces and the corresponding ceramic for each metal was fired onto them. The thickness of the ceramic layer was standardized by positioning the frameworks in a metallic template (height: 1 mm). The specimens from each ceramic-metal combination (N=96, n=12 per group) were randomly assigned into four experimental fatigue conditions, namely water storage at 37 degrees C for 24h (control group), thermal cycling (3000 cycles, between 4 and 55 degrees C, dwell time: 10s), mechanical cycling (20,000 cycles under 10 N load, immersion in distilled water at 37 degrees C) and, thermal and mechanical cycling. A flexural strength test was performed in a universal testing machine (crosshead speed: 1.5 mm/min). Data were statistically analyzed using two-way ANOVA and Tukey's test (alpha=0.05). RESULTS: The mean flexural strength values for the ceramic-gold alloy combination (55+/-7.2MPa) were significantly higher than those of the ceramic-Ti cp combination (32+/-6.7 MPa) regardless of the fatigue conditions performed (p<0.05). Mechanical and thermo-mechanical fatigue decreased the flexural strength results significantly for both ceramic-gold alloy (52+/-6.6 and 53+/-5.6 MPa, respectively) and ceramic-Ti cp combinations (29+/-6.8 and 29+/-6.8 MPa, respectively) compared to the control group (58+/-7.8 and 39+/-5.1 MPa, for gold and Ti cp, respectively) (p<0.05) (Tukey's test). While ceramic-Ti cp combinations failed adhesively at the metal-opaque interface, gold alloy frameworks exhibited a residue of ceramic material on the surface in all experimental groups. SIGNIFICANCE: Mechanical and thermo-mechanical fatigue conditions decreased the flexural strength values for both ceramic-gold alloy and ceramic-Ti cp combinations with the results being significantly lower for the latter in all experimental conditions.     

Adhesive bonding of titanium-aluminum-niobium alloy with nine surface preparations and three self-curing resins

The purpose of the current study was to evaluate the adhesive performance of metal conditioners when used for bonding between auto-polymerizing methacrylic resins and a titanium alloy. Disk specimens were cast from a titanium-aluminum-niobium (Ti-6Al-7Nb) alloy, air-abraded with alumina, and bonded with 24 combinations of eight metal conditioners (Acryl Bond, ACB; All-Bond 2 Primer B, ABB; Alloy Primer, ALP; Cesead II Opaque Primer, COP; Metafast Bonding Liner, MBL; Metal Primer II, MPII; MR Bond, MRB; Super-Bond liquid, SBL) and three autopolymerizing methacrylic resins (Repairsin, RE; Super-Bond C & B, SB; Tokuso Rebase; TR). Unprimed specimens were used as controls. Shear bond strengths were determined both before and after thermocycling (4-60 degrees C, 20, 000 cycles). The ALP-SB group recorded the greatest post-thermocycling bond strength (21.8 MPa) followed by the COP-SB group (17.8 MPa) and the MPII-SB group. The post-thermocycling bond strengths of the unprimed-SB group and the ALP-RE group were statistically comparable. No significant differences were found among the nine TR resin groups, and these groups showed the lowest bond strength. In conclusion, the use of one of the three conditioners (ALP, COP, and MPII) in combination with the SB resin is recommended for bonding the Ti-6Al-7Nb alloy.     

Effects of primers containing sulfur and phosphate monomers on bonding type IV gold alloy

OBJECTIVE: The purpose of the present study was to evaluate the effect of five primers (two sulfur, one phosphate, and two sulfur-phosphate dual-function primers) on the bond strength between a self-curing luting agent and gold-copper-silver (Au-Cu-Ag) alloy. METHODS: The primers used were two sulfur primers (V-Primer and Metaltite), one phosphate primer (Epricord), and two primers which contained a sulfur monomer and a phosphate monomer (Alloy Primer and Metaltite/Epricord). The surface of Au-Cu-Ag specimens were blasted with alumina, and then bonded with acrylic rods using a tri-n-butylborane-initiated self-curing luting agent. Shear bond strengths were determined after 5000 thermocycles. An additional alumina-blasted Au-Cu-Ag alloy specimen was subjected to X-ray photoelectron spectroscopy (XPS) analysis. RESULTS: The maximum shear bond strengths were obtained with Metaltite/Epricord (29.6+/-2.3 MPa) and Alloy Primer (23.0+/-1.6 MPa), followed by Metaltite (10.3+/-4.2 MPa), V-Primer (8.9+/-0.6 MPa), Epricord (6.4+/-1.5 MPa), and No primer control (2.0+/-0.5 MPa). The XPS analysis detected six chemical elements (Au, Cu, Ag, Al, O, and C) on the Au-Cu-Ag alloy. In addition to pure Au element, the metal oxide-states of Ag2O, AgO, Cu2O, and CuO were suggested. CONCLUSION: The combined use of a sulfur monomer and a phosphate monomer significantly improved the bond strength of resin to Au-Cu-Ag alloy which should be especially significant to clinicians.     

Effect of noble metal conditioners on bonding between prosthetic composite material and silver-palladium-copper-gold alloy

STATEMENT OF PROBLEM: Mechanical retentive devices and the application of complicated surface preparation have been indispensable for bonding composite material to the metal substructure of restorations. PURPOSE: This study evaluated the priming effects of 4 metal conditioners on bonding between a prosthetic veneering material and a silver-palladium-based casting alloy. MATERIAL AND METHODS: Four primers designed for conditioning noble metal alloys (Alloy Primer, Metaltite, Metal Primer II, and V-Primer) were assessed (all materials contain organic sulfur compounds). Cast disk specimens made of silver-palladium-copper-gold alloy (Castwell M.C.12) were primed with 1 of the 4 primers, and bonded with a light-activated prosthetic composite material (Axis). Shear testing was performed before and after thermocycling for evaluation of bond durability. RESULTS: All primed groups showed improved 24-hour bond strengths compared with the unprimed group. After thermocycling, 3 groups primed with the Metal Primer II, Alloy Primer, and Metaltite agents exhibited the highest bond strength. CONCLUSION: Use of 1-liquid metal conditioners containing sulfur compounds was a simple and useful method for improving bonding between the alloy and the composite material tested.     

Effect of metal primers and tarnish treatment on bonding between dental alloys and veneer resin

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.     

Shear bond strength of resin composite veneering material to gold alloy with varying metal surface preparations

STATEMENT OF PROBLEM: Although adequate surface preparation is indispensable to achieve a consistent and durable bond between resin composite materials and the metal substructures of veneered restorations, information on the bonding performance of current metal adhesive systems is limited. PURPOSE: The purpose of this study was to evaluate the surface preparation effects of 4 metal conditioners and 1 adhesive system on bonding between a prosthetic resin composite veneering material and a gold casting alloy. MATERIAL AND METHODS: Four primers containing sulfur derivative monomer and designed for conditioning noble metal alloys (Alloy Primer, Infis Opaque Primer, Metal Primer II, and Metaltite) and a surface modification technique (Siloc) were assessed. Cast disk specimens made of gold alloy (Pontor LFC) were either primed with 1 of the 4 primers or treated with the Siloc system and bonded with a light-activated prosthetic resin composite material (New Metacolor Infis). Control specimens were also prepared without the use of a bonding agent. Shear bond strengths were determined before and after thermocycling (20,000 cycles) for evaluation of bond durability. RESULTS: All of the primed and Siloc-treated groups showed improved 24-hour shear bond strengths compared with the control group. After thermocycling, the groups either primed with the Metaltite conditioner or treated with the Siloc system exhibited the highest mean shear bond strengths. CONCLUSION: The Metaltite conditioner and Siloc system each represent a useful method for improving the bond between the gold alloy and resin composite material tested.     

Effectiveness of Adhesive Systems for a Co–Cr Removable Partial Denture Alloy

Purpose In vitro bond strengths of traditional denture base acrylic resin (Lucitone 199) to a cobalt-chromium partial denture alloy (J.D. Partial Denture Alloy) were tested using two surface pretreatments (sandblast, sandblast and electrochemical etch) with three adhesive primers: Lee Metal Primer, Acrylic Solder, and CR Inlay cement. A sandblasted group with no primer served as the control. Materials and Methods The alloy specimens (8.0-mm bonding diameter) were cast and invested to receive a traditional denture base resin after surface treatments (sandblasted, and sandblasted-electrochemically etched) and application of adhesive primers. The bonded specimens were stored in distilled water at 37°C for 24 hours and divided into two groups. The first group was debonded in tension on a testing machine at a cross-head speed of 0.05 cm/min. The second group was subjected to thermocycling of 1,000 cycles and then tested for tensile bond strength. The force at which the bond failed was recorded, and the bond strength was calculated in megapascals (MPa). The sites of bond failure were examined, quantified under (20x) magnification, and recorded. Ten specimens were evaluated for each experimental condition for a total of 160 specimens. Data were analyzed by ANOVA with a factorial design. Means were compared by Tukey intervals at the 0.05 significance level. Results Significant differences in bond strength were observed, with primers being the most important factor, followed by pretreatment and storage and thermocycling with significant interactions. Sandblasted-electrochemically etched alloy with primers more effectively enhanced bond strength of the denture base resin to the treated alloy than sandblasted alloy with primers. Thermocycling had a greater effect on bond strength of the specimens with Acrylic Solder when compared with Lee and CR Inlay primers. The highest bond strengths (>18.0 MPa) were observed for the conditions involving electrochemical etching and the priming with CR Inlay cement (both after 24 hours and thermocycling of 1,000 cycles). For primed specimens, the bond failures occurred cohesively within the primers or the denture resin and adhesively between the primers and the denture base resin, or between primers and alloy. For nonprimed, the bond failures occurred adhesively at the denture base resin-metal interface. Conclusions Nonprimed specimens (both sandblasted and electrochemically etched) had lowest bond strength (0.4 ± 0.1 MPa; 0.3 ± 0.4 MPa). The bond strengths of the primed treated specimens were improved significantly. The CR Inlay-treated specimens exhibited the highest bond strength (20.6 ± 6.3 MPa). After thermocycling for 1,000 cycles, the bond strengths of the specimens were significantly lower than the bond strengths of the specimens after 24 hours.     

Effects of primers containing thiouracil and phosphate monomers on bonding of resin to Ag-Pd-Au alloy

The purpose of the present study was to evaluate the effects of four experimental primers on bond strength between a self-curing luting agent and silver-palladium-gold alloy. The experimental primers were in mixed solutions of a thiouracil primer (Metaltite) and a phosphate primer (Epricord, PM, PE, or PP), which were designated as Metaltite/Epricord, Metaltite/PM, Metaltite/PE, and Metaltite/PP respectively. Three primers (Metal Primer II, V-Primer, and Alloy Primer) were also prepared as controls. Alumina-blasted metal alloys were bonded with acrylic rods. After 5,000 thermocycles, the maximum shear bond strength was obtained with Metaltite/PE (27.8+/-2.4 MPa) and Metaltite/Epricord (27.6+/-5.9 MPa), followed by Metaltite/PP, Alloy Primer, Metaltite, Metaltite/PM, Metal Primer II, V-Primer, and Epricord. PE, PM, and PP showed the lowest bond strength. Results of this study revealed that the combined use of a thiouracil monomer and a phosphate monomer improved adhesive bonding. In this light, clinicians should pay attention to the types of functional monomers dissolved in a primer when fabricating resin-bonded prostheses.     

Effect of three adhesive primers for a noble metal on the shear bond strengths of three resin cements

The purpose of this study was to evaluate the durability and shear bond strengths of the different combinations of three adhesive primers and three resin cements to a silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy. The adhesive primers Alloy Primer (AP), Metal PrimerII (MPII) and Metaltite (MT), and the resin cements BistiteII (BRII), Panavia Fluoro Cement (PFC) and Super-Bond C&B (SB) were used. Two sizes of casting alloy disks were either non-primed or primed and cemented with each of the three resin cements. The specimens were stored in a 37 degrees C water bath for 24 h and then immersed alternately in 4 and 60 degrees C water baths for 1 min each for up to 100,000 thermal cycles. Shear mode testing at a crosshead speed of 0.5 mm/min was then performed. The application of MPII or MT was effective for improving the shear bond strength between each of the three resin cements and the Ag-Pd-Cu-Au alloy compared with non-primed specimens. However, when primed with MPII or MT and cemented with SB, the bond strength at 100,000 thermal cycles was significantly lower than that at thermal cycle 0. When primed with AP, the specimens cemented with BRII or PFC showed lower bond strength than non-primed specimens and failed at the metal-resin cement interface at 100,000 thermal cycles. On the other hand, AP was effective in enhancing the shear bond strength of SB to the Ag-Pd-Cu-Au alloy. The five combined uses of an adhesive metal primer and resin cement (combinations of MPII or MT and BRII or PFC and AP and SB) are applicable to the cementation of prosthodontic restorations without complicated surface modification of the noble alloy.     

Bond Strength of Resin Cements to Co‐Cr and Ni‐Cr Metal Alloys Using Adhesive Primers

Purpose: The aim of this study was to evaluate the effectiveness of adhesive primers (APs) applied to Co‐Cr and Ni‐Cr metal alloys on the bond strength of resin cements to alloys. Materials and Methods: Eight cementing systems were evaluated, consisting of four resin cements (Bistite II DC, LinkMax, Panavia F 2.0, RelyX Unicem) with or without their respective APs (Metaltite, Metal Primer II, Alloy Primer, Ceramic Primer). The two types of dental alloys (Co‐Cr, Ni‐Cr) were cast in plate specimens (10 × 5 × 1 mm³) from resin patterns. After casting, the plates were sandblasted with aluminum oxide (100 μm) and randomly divided into eight groups (n = 6). Each surface to be bonded was treated with one of eight cementing systems. Three resin cement cylinders (0.5 mm high, 0.75 mm diameter) were built on each bonded metal alloy surface, using a Tygon tubing mold. After water storage for 24 hours, specimens were subjected to micro‐shear testing. Data were statistically analyzed by two‐way ANOVA and Tukey's studentized range test. Results: The application of Metal Primer II resulted in a significantly higher bond strength for LinkMax resin cement when applied in both metal alloys. In general, the cementing systems had higher bond strengths in Co‐Cr alloy than in Ni‐Cr. Conclusions: The use of AP between alloy metal surfaces and resin cements did not increase the bond strength for most cementing systems evaluated.     

Tensile bond strength of resin-modified glass-ionomer cement to microabraded and silica-coated or tin-plated high noble ceramic alloy

PURPOSE: The purpose of this study was to evaluate the influence of alloy surface microabrasion, silica coating, or microabrasion plus tin plating on the tensile bond strengths between a resin-modified glass-ionomer luting cement and a high-noble alloy. Bond strength between the microabraded alloy specimens and conventional glass-ionomer cement or resin cement were included for comparison. MATERIALS AND METHODS: One hundred twenty uniform size, disk-shaped specimens were cast in a noble metal alloy and divided into 6 groups (n = 10 pairs/group). The metal surfaces of the specimens in each group were treated and cemented as follows. Group 1: No surface treatment (as cast, control), cemented with a resin-modified glass-ionomer cement. Group 2: Microabrasion with 50-microm aluminum oxide particles, resin-modified glass-ionomer cement. Group 3: A laboratory microabrasion and silica coating system, resin-modified glass-ionomer cement. Group 4: Microabrasion and tin-plating, resin-modified glass-ionomer cement. Group 5: Microabrasion only, conventional glass-ionomer cement. Group 6: Microabrasion and tin-plating, conventional resin cement. The uniaxial tensile bond strength for each specimen pair was determined using an Instron Universal Testing Machine (Instron Corp, Canton, MA). Results were analyzed using a one-way analysis of variance (alpha = 0.05) and a Tukey post-hoc analysis. RESULTS: Mean bond strength: Group 1: 3.6 (+/- 1.5) MPa. Group 2: 4.2 (+/-0.5) MPa. Group 3: 6.7 (+/- 0.9) MPa. Group 4: 10.6 (+/- 1.8) MPa. Group 5: 1.1 (+/- 0.4) MPa. Group 6: 14.6 (+/- 2.3) MPa. Group 6 was significantly stronger than Group 4. The bond strength of specimens cemented with the resin-modified glass-ionomer cement using microabrasion and tin-plating (Group 4) was significantly stronger than all other groups except the resin cement with microabrasion and tin-plating (Group 6). CONCLUSION: Microabraded and tin-plated alloy specimens luted with the resin-modified glass-ionomer cement resulted in the greatest mean tensile strengths for the resin-modified glass-ionomer cement groups. This strength was 73% of the mean tensile strength of microabraded specimens luted with resin cement.     

Effect of drying time of 3-methacryloxypropyltrimethoxysilane on the shear bond strength of a composite resin to silica-coated base/noble alloys.

OBJECTIVES: In this in vitro study, the effect of various drying (surface reaction) times of a commercial silane, other than that recommended by the manufacturer (at least 5 min), on the bond strength between the resin composite and silica coated base and noble alloys was evaluated. METHODS: A total of 112 disc specimens (9 mm diameter and 0.5 mm thickness) were cast out of two types of alloy designed for ceramic firing, one of which was a noble (Degunorm) (gold-silver-platinum) and the other a base alloy (Wiron 99) (nickel-chromium-molybdenum). The specimens were assigned to two main groups according to each alloy type. These two main groups were further divided into seven subgroups, having eight specimens each. The specimens of both alloy types were air-abraded with 30 microm silica (SiO2) coated alumina (Al2O3) (CoJet-Sand, ESPE, Seefeld, Germany). The conditioned surfaces were coated with 3-methacryloxypropyltrimethoxysilane (MPS) and were allowed to react and dry for 1, 2, 3, 4, 5, 6, and 7 min, respectively, before the opaquer was applied. Immediately after the waiting periods for the silane to dry, first opaquer and then resin composite were applied. After storage in water for 30 days at 37 degrees C and thermocycling (5000 cycles, 5-55 degrees C), shear tests were performed using the universal testing machine at a crosshead speed of 0.5 mm/min. RESULTS: Analysis of data showed no significant difference in bond strength for any silane drying and reaction period for both base and noble alloys between 1 and 7 min (ANOVA, P = 0.05) (Degunorm: 5.8 - 7.4 MPa and Wiron 99: 7.2 - 10.2 MPa, respectively). Bond strengths of resin composite to base alloys were significantly higher than those to noble alloys at 2, 3 and 5 min (P = 0.0045, P = 0.05, P = 0.002, respectively). SIGNIFICANCE: In order to optimize the flow of laboratory work, the silane solution drying time might be reduced to 1 min for both base and noble alloys.     

Effect of three adhesive primers on the bond strengths of four light-activated opaque resins to noble alloy

The effect of commercial adhesive primers for noble metals on the bond strength of light-activated opaque resin has not been determined. This study evaluated the effect of three adhesive primers on the shear bond strengths of each of the four light-activated opaque resins to silver--palladium--copper--gold (Ag--Pd--Cu--Au) alloy. The adhesive primers Alloy Primer (AP), Metal Primer II (MPII) and Metaltite(MT) were used. Four commercial light-activated opaque resins (Axis (AX), Cesead II (CEII), Dentacolor(DE) and Solidex (SO) were used to bond a light-activated resin-veneered composite to Ag--Pd--Cu--Au alloy. The specimens were stored in water at 37 degrees C for 24 h and then immersed alternatively in water baths at 4 and 60 degrees C for 1 min each for up to 20,000 thermal cycles before shear mode testing at a cross-head speed of 0.5 mm min(-1). All the primers examined improved the shear bond strength between opaque resin and Ag--Pd--Cu--Au alloy compared with non-primed specimens prior to thermal cycling. After 20,000 thermal cycles, the bond strengths of combined use of AP and DE and that of MT and each of AX, CE or DE were significantly greater than any other groups. Significant difference was observed between the bond strengths at thermal cycles 0 and 20,000, with the combined use of MT and DE. With the combination of appropriate adhesive metal primers and light-activated opaque resins, complicated surface preparations of metal frameworks of resin-veneered prostheses that are composed of casting Ag-Pd-Cu-Au alloy may be negligible.     

Adhesive bonding of composite material to cast titanium with varying surface preparations

The purpose of the present study was to evaluate the surface preparation effects of eight metal conditioners and an adhesive system on bonding between a prosthodontic composite material and cast titanium. Eight primers designed for conditioning base metal alloys (Acryl Bond, All-Bond 2 Primer B, Alloy Primer, Cesead II Opaque Primer, Eye Sight Opaque Primer, Metafast Bonding Liner, Metal Primer II, and MR Bond) as well as a surface modification technique (Siloc) were assessed. Disk specimens cast from titanium (T-Alloy H) were either primed with one of the eight primers or treated with the Siloc system, and then bonded with a light-activated composite material (Artglass). Bond durability was evaluated by thermocycling (4 and 60 degrees C, 1 min each, 20, 000 cycles). After thermocycling, two groups either primed with the Cesead II Opaque Primer material or treated with the Siloc system exhibited significantly greater bond strength (20.0 and 19.0 MPa) than the other groups (0.2-12.6 MPa, P < 0.05). These two systems are considered to be useful for improving bonding between the titanium and the composite material tested.     

Bond strength to primed Ti-6Al-7Nb alloy of two acrylic resin adhesives

This study aimed to evaluate the bonding behavior of two acrylic resin adhesives joined to titanium-aluminum-niobium (Ti-6Al-7Nb) alloy primed with two metal conditioners. Cast Ti-6Al-7Nb alloy disks were air-abraded with alumina and bonded with six combinations of two resin adhesives (Super-Bond C&B and Multi Bond) and three surface conditions (Alloy Primer, M.L. Primer, and unprimed control). Shear bond strengths were determined both before and after 20,000 thermal cycles. The tri-n-butylborane initiated Super-Bond C and B resin exhibited greater bond strength than the BPO-amine initiated Multi-Bond resin. Both the Alloy Primer with a hydrophobic phosphate and the M.L. Primer with a phosphonoacetate effectively improved the 24-hour bond strength of Multi-Bond resin as well as the post-thermocycling bond strength of Super-Bond C and B resin.