Metal Primer Research Articles

Influence of the Combined Application of an Adhesive Metal Primer and a Silane Coupling Agent on Bond Strengths between a Gold-silver-palladium Alloy and a Resin Composite

Influence of the Combined Application of an Adhesive Metal Primer and a Silane Coupling Agent on Bond Strengths between a Gold-silver-palladium Alloy and a Resin Composite

Adhesive bonding of resin cements to cast titanium with adhesive primers

The purpose of this study was to evaluate the effects of adhesive primer applications on the bond strength of resin cements to cast titanium. Four adhesive primers - Metaltite, Metal Primer II, Alloy Primer and Ceramic Primer - and their respective resin cements - Bistite II DC, Link Max, Panavia F 2.0, RelyX Unicem and RelyX ARC - were tested. Cast plates were prepared from titanium ingots (n=6 specimens/cement) and had their surfaces airborne-particle abraded with Al2O3 (50 μ m). Three resin cement cylinders were built on each bonded titanium surface, using a cylindrical translucent tubing mold and were subjected to micro-shear testing. Data were analyzed statistically by two-way ANOVA and Tukey's post-hoc test (α=0.05). The application of Metal Primer II and Ceramic Primer resulted in significant higher bond strength for Link Max and RelyX Unicem resin cements, respectively, than nonuse of adhesive primers. Panavia F 2.0 and RelyX ARC yielded high bond strength means with or without adhesive primers. The use of adhesive primers might increase the bond strength to cast titanium depending on the resin cement used.

Effects of metal primers on the bonding of an adhesive resin cement to noble metal ceramic alloys after thermal cycling

Although the effectiveness of primers for resin bonding to noble alloys has been demonstrated, no effective clinical technique for bonding to noble metal ceramic alloys has been established. The purpose of this study was to evaluate the effects of metal primers on the shear bond strength of an adhesive resin to noble metal ceramic alloys after thermal cycling. Sixty-three disk-shaped specimens (10 × 2.5 mm) were cast from high-gold-content alloys (Super Metal W-85: W85 or IFK88 GR: IFK88), a high-palladium-content alloy (Super Metal N-40: N40), and an Ag-Pd-Cu-Au alloy (Castwell M.C.12: MC12). Smaller-sized disk-shaped specimens (8 × 2.5 mm) were fabricated with MC12. Bonding surfaces were finished with 600-grit SiC-paper and airborne-particle abraded with 50-μm alumina. Pairs of disks were primed (V-Primer: VP; ML Primer: ML; or Metaltite: MT) and bonded with an adhesive resin (Super-Bond C&B). The bond strengths were determined before and after 20,000 and 50,000 thermal cycles (n=7). Data were analyzed by using a 3-way ANOVA and the Bonferroni test (α=.05). Failure modes were determined by optical microscope and SEM observation. Bond strengths to high-gold-content alloys with VP and MT significantly decreased after the thermal cycling (P<.001). Bond strengths to W85 (35.27 ±4.25 MPa) and IFK88 (33.57 ±3.56 MPa) after 50,000 thermal cycles obtained by ML were the highest (P<.001), and these groups showed combination failures. Bond strengths to N40 significantly decreased after 50,000 thermal cycles (P<.001), regardless of primers. Shear bond strengths (SBS) to high-gold-content alloys were not degraded up to 50,000 thermal cycles when primed with ML. None of the primers evaluated was effective for high-palladium-content alloy.

Effects of Different Surface Conditioning Methods on the Bond Strength of Composite Resin to Amalgam

Repairing amalgam restorations with composite resins using surface conditioning methods is a conservative treatment approach. This study investigated the effects of different conditioning methods that could be used for repair of amalgam fractures. Amalgam (N=96) was condensed into cavities within autopolymerizing polymethylmethacrylate (PMMA), and the exposed surface of each specimen (diameter, 6 mm; thickness, 2 mm) was ground finished. The specimens were randomly divided into nine experimental groups (n=12 per group), depending on the conditioning method used. The control group had natural central incisors with amalgam (n=12). The combination of the following conditioning methods was tested: silicacoating (Sc), sandblasting (Sb), metal primers, coupling agents, fiber (Fb) application, and opaquers (O). Five types of silanes, metal primers, or adhesives (Visiobond [V], Porcelain Photobond [PP], Alloy Primer [AP], Unibond sealer [Us], ESPE-Sil [ES]), and four opaquers, namely, Clearfil St Opaquer (CstO), Sinfony (S), Miris (M), and an experimental Opaquer (EO-Cavex), were used. The groups were as follows: group 1, Sc+ES+S+V; group 2, Sc+ES+CstO+V; group 3, Sc+ES+M+V; group 4, Sc+ES+EO+V; group 5, Sb+AP+S; group 6, Sb+AP+PP+CstO; group 7, Sc+ES+S+Fb+V+Fb; group 8-control, SC+ES+V; and group 9, Etch+Sc+ES+S+Us. One repair composite was used for all groups (Clearfil Photo Bond Posterior, Kuraray, Tokyo, Japan). Shear bond strengths (SBSs) (MPa ± SD) were evaluated after 5 weeks of water storage (analysis of variance [ANOVA], Tukey honestly significant differences [HSD], α=0.05). Group 1 exhibited significantly higher values (35.5 ± 4.1) than were seen in group 4 (19.4 ± 8.9), group 6 (19.1 ± 7.8), and group 8 (20.1 ± 4.1) (p<0.05). Group 9 exhibited significantly lower values (8.3 ± 3.4) than were noted in groups 1 to 3 (35.5 ± 4.1; 27 ± 12.5; 24.4 ± 5.1, respectively) (p<0.05). Group 7 (16.4 ± 5.9) showed significantly lower values than were observed in group 1 (35.5 ± 4.1) (p<0.05). Surface conditioning techniques affected the bond strengths of composite adhesion to amalgam. Experimental opaquer exhibited lower values. Leaving a small border of enamel around the restoration decreased the bond strength.

Effect of metal primers on microtensile bond strength between zirconia and resin cements

There are no established clinical procedures for bonding zirconia to tooth structure using resin cements. The purpose of this study was to evaluate the influence of metal primers, resin cements, and aging on bonding to zirconia. Zirconia was treated with commercial primers developed for bonding to metal alloys (Metaltite, Metal Primer II, Alloy Primer or Totalbond). Non-primed specimens were considered as controls. One-hundred disk-shaped specimens (19 × 4 mm) were cemented to composite resin substrates using Panavia or RelyX Unicem (n=5). Microtensile bond strength specimens were tested after 48 hours and 5 months (150 days), and failure modes were classified as type 1 (between ceramic/cement), 2 (between composite resin/cement) or 3 (mixed). Data were analyzed by 3-way ANOVA and Multiple Comparison Tukey test (α=.05). The interactions primer/luting system (P=.016) and luting system/storage time (P=.004) were statistically significant. The use of Alloy Primer significantly improved the bond strength of RelyX Unicem (P<.001), while for Panavia, none of the primers increased the bond strength compared to the control group. At 48 hours, Panavia had statistically higher bond strength (P=.004) than Unicem (13.9 ± 4.4 MPa and 10.2 ± 6.6 MPa, respectively). However, both luting systems presented decreasing, statistically similar, values after aging (Panavia: 3.6 ± 2.2 MPa; Unicem: 6.1 ± 5.3 MPa). At 48 hours, Alloy Primer/Unicem had the lowest incidence of type 1 failure (8%). After aging, all the groups showed a predominance of type 1 failures. The use of Alloy Primer improved bond strength between RelyX Unicem and zirconia. Though the initial values obtained with Panavia were significantly higher than RelyX Unicem, after aging, both luting agents presented statistically similar performances.

A study of self-adhesive resin cements for bonding to silver-palladium-copper-gold alloy &amp;mdash; Effect of including primer components in cement base

This study investigated the efficacies of adhesive resin cements (Clearfil SA Luting, Maxcem, G-CEM, RelyX Unicem Clicker, Vitremer Paste) for bonding to Ag-Pd-Cu-Au alloy not surface-pretreated with metal primer. For control, Panavia F 2.0 -developed for use with a proprietary metal primer, Alloy Primer- was tested with and without metal primer application. Pairs of alloy disks (10.0 and 8.0 mm in diameters, 3.0 mm thickness) were air-abraded with alumina and bonded with one of the cements. Shear bond strengths (SBSs) were measured before and after 50,000 times of thermocycling. Among Maxcem, RelyX Unicem Clicker and the control, there were no statistical differences in SBS before and after thermocycling. After thermocycling, Clearfil SA Luting exhibited the highest SBS among all the cements. Results showed that Clearfil SA Luting, Maxcem, and RelyX Unicem Clicker were efficacious for bonding to Ag-Pd-Cu-Au alloy after air abrasion surface treatment for the latter.

Design of a metal primer containing a dithiooctanoate monomer and a phosphonic acid monomer for bonding of prosthetic light-curing resin composite to gold, dental precious and non-precious metal alloys

The effect of metal primers on adhesion of a resin composite to dental metal alloys was investigated. Experimental primers containing a dithiooctanoate monomer [10-methacryloyloxydecyl 6,8-dithiooctanoate (10-MDDT) or 6-methacryloyloxyhexyl 6,8-dithiooctanoate (6-MHDT)] and a phosphonic acid monomer [6-methacryloyloxyhexyl phosphonoacetate (6-MHPA) or 6-methacryloyloxyhexyl 3-phosphonopropionate (6-MHPP)] were prepared. After treating Au, Au alloy, Ag alloy, Au-Ag-Pd alloy, and Ni-Cr alloy with the experimental primers, their shear bond strengths (SBSs) with a prosthetic light-curing resin composite (Solidex, Shofu Inc., Japan) were measured after 1-day storage followed by 5,000 thermal cycles. The SBSs between Solidex and the primer-treated metals which were incubated in air at 50°C for 2 months were further measured. Results showed that the SBSs [mean (SD)] of all metal adherends treated with primer DT-PA-1 (5.0 wt% 10-MDDT, 1.0 wt% 6-MHPA) ranged between 31.2 (5.2) and 34.5 (5.8) MPa. The SBSs of the primer-treated metals did not degrade after 2-month incubation at 50°C. Therefore, a combined primer application consisting of a dithiooctanoate monomer and a phosphonic acid monomer provided efficacious bonding to Au as well as precious and non-precious metal alloys.

The Effect of Metal Primer Application and Nd:YAG Laser Irradiation on the Shear-Bond Strength Between Polymethyl Methacrylate and Cobalt-Chromium Alloy

The purpose of this study was to compare the shear-bond strengths (SBSs) of an acrylic resin and a cobalt-chromium (Co-Cr) alloy after applying a metal primer, Nd:YAG laser irradiation, or both to the sandblasted surface of the Co-Cr alloy. The serviceability of a removable partial denture (RPD) is dependent on the bond strength at the resin-alloy interface. No previously published studies exist on the use of Nd:YAG lasers for preparing the surface of a Co-Cr alloy in an RPD to obtain a high-strength bond between PMMA and the alloy. One-hundred twenty Co-Cr alloy specimens were sandblasted and randomly assigned to four equal groups: Group I, sandblasting; Group II, sandblasting + metal primer; Group III, sandblasting + Nd:YAG laser; and Group IV, sandblasting + Nd:YAG laser + metal primer. To establish the most appropriate fluence for modifying the surface of the sandblasted cast specimens, we conducted a preliminary study. Nd:YAG laser irradiation at a fluence of 46.9 J/cm(2) was selected. After the various surface treatments, each alloy specimen was embedded in PMMA to determine the SBS between PMMA and the alloy. Group II and III specimens exhibited higher SBSs than did those of the Group I specimens (p < 0.05), and Group IV specimens showed higher SBSs than did those of the Group II and III specimens (p < 0.05). A significant difference existed in failure types among groups (p < 0.05). Failure type was predominantly adhesive for groups I and III, but predominantly mixed for groups II and IV. Nd:YAG laser irradiation at a fluence of 46.9 J/cm(2) roughens the sandblasted surface of a Co-Cr alloy and increases the strength of the bond between PMMA and the alloy. This bond strength can be increased further by applying a metal primer to the laser-irradiated surface.

Effect of sandblasting and various metal primers on the shear bond strength of resin cement to Y-TZP ceramic

Objectives This study was designed to evaluate the effect of sandblasting and metal primers on the shear bond strength of three commercial resin cements to Yttria-Tetragonl Zirconia Polycrystal (Y-TZP) ceramics. Methods One hundred and twenty Y-TZP ceramic cylinders (Ø7 mm × 12 mm) were embedded in polytetrafluoroethylene (PTFE) molds using PMMA. The specimens were divided randomly into 12 groups ( n = 10), according to the surface treatments (control; sandblast-only; metal primer-only; sandblast + metal primer) and metal primer-resin cements (Alloy primer – Panavia F 2.0, V-primer – Superbond C&B, Metaltite – M bond) rendered. The mixed resin cements were placed onto the treated zirconia surfaces in cylindrical shape (Ø3 mm × 3 mm) using PTFE molds. All specimens were thermocycled (5 and 55 °C, 5000 cycles) and subjected to shear bond strength test by a universal testing machine with a crosshead speed of 0.5 mm/min. All data were statistically analyzed using two-way ANOVA and multiple comparison Scheffé test ( α = 0.05), and SEM images of the fractured areas were used to evaluate the fracture mode. Results In Panavia F 2.0, the bond strength of the specimens treated with sandblasting and metal primer (Alloy primer) was significantly higher than those of the other subgroups. In Superbond C&B and M bond, sandblasting significantly increased the shear bond strength, but the effect of metal primers (V-primer and Metaltite) was not significant and there was disordinal interaction. Significance Metal primers are not always effective for bonding between Y-TZP ceramics and resin cements. Even though a metal primer is not enough to be used alone, combined application with sandblasting seems to be an appropriate pretreatment for improving the bond strength of resin cement to Y-TZP ceramics, especially in Panavia F 2.0.

The effect of primers on shear bond strength of acrylic resins to different types of metals

Poor chemical bonding of acrylic resins to metal alloys can result in microleakage and failure of the bond. Metal primers have been shown to be effective in improving the bond strength of acrylic resins to metal alloys. However, there is insufficient information about their effects on bonding to different types of metals. The purpose of this study was to evaluate the effect of metal primers on the shear bond strength of acrylic resins to 3 different types of metals. A total of 432 disk-shaped wax patterns (10 mm in diameter and 2 mm thick) were cast in a Ti alloy (Tritan), base metal (Co-Cr alloy, Wironit), or noble metal (Au-Ag-Pt alloy, Mainbond EH). After casting, the disk surfaces were finished with abrasive paper under water. The noble alloy was airborne-particle abraded with 50-microm aluminum oxide; the other alloys were airborne-particle abraded with 110-mum aluminum oxide for 10 seconds. Specimens of each metal were divided into 3 groups (n=48) and received 1 of the following acrylic resins: (1) heat polymerized (Meliodent), (2) autopolymerized (Meliodent), or (3) microwave polymerized (Acron MC). The specimens were then divided into 4 subgroups (n=12) which received 1 of the following metal primers: (1) Metal Primer, (2) Alloy Primer, (3) Meta Fast, or (4) no primer (control). All specimens were stored in distilled water at 37 degrees C for 24 hours after polymerization and then thermal cycled (5000 cycles at 5-55 degrees C with a 30-second dwell time). After thermal cycling, the specimens were tested in a universal testing machine at a crosshead speed of 0.5 mm/min in shear mode. Data (MPa) were analyzed using 3-way ANOVA and the post hoc Tukey HSD test (alpha=.05). The 3-way ANOVA indicated that shear bond strength (SBS) values varied according to the metal type, metal primer, and acrylic resin used (P<.001). The SBS between base metal and heat-polymerized resin with Metal Primer was the highest (3.6 +/-0.67 MPa), and the SBS between noble metal and acrylic resin, for all control groups, was the lowest (0.4 +/-0.07 MPa) (P<.001). For titanium, the highest SBS was observed for Meta Fast and the lowest for the control group. For base metal, the highest SBS was recorded for Metal Primer and the lowest for the control group, while for noble metal, the highest SBS was observed for Alloy Primer and the lowest for the control group (P<.001). The metal primers were associated with an increase in the adhesive bonding of acrylic resins to metal alloys. The SBS of the acrylic resin to the base metal alloy was significantly higher than the SBS to the noble and titanium alloys.

Variables related to materials and preparing for bond strength testing irrespective of the test protocol

IntroductionResin bonding can be compared to making a sandwich with the tooth on one side and the restoration on the other, a layer of bonding resin is applied to either side and a filled resin (composite) placed in between. This presentation considers factors that influence the restoration side of the sandwich and various ways that the assembled testpieces may be “aged” prior to testing. The materials to be bonded may be either ceramic, metal or composite formed by methods such as casting, pressing, sintering or machining. The fabrication method determines the susceptibility of the bonding surface to physical or chemical modification. The treatment of the surface prior to bonding can be physical (e.g. sandblasting) or chemical (e.g. metal primer); but is more likely to be a combination (e.g. silica deposition+silane). Preparation of the bonding surfaceSuccessful bonding depends on establishing a surface with a high population of unreacted vinyl groups (–CC) that can then be cross-polymerized to the resin in the bonding composite. The physical approach has involved etching or sandblasting the surfaces; but the ability to form a microretentive surface in this way depends on a heterogeneous surface. Noble metals and modern high strength ceramics have a more homogeneous surface and are not easily etched. To overcome this problem a number of ways to deposit a silica layer on the bonding surface have been developed: the Silicoater that involves baking on a silica layer, the Rocatec technique (CoJet) that involves air blasting silica onto the surface in conjunction with an abrasive; and two more modern approaches: sol–gel evaporation and molecular vapor deposition (MVD). All these techniques require the subsequent application of a silane layer to provide the –CC moieties. The use of primers without an intervening silica layer has been tested and found to be successful with some specialized bonding systems that contain agents such as methacryloyloxydecyldihydrogen-phosphate (MDP) (PanaviaEX). Aging of testpieces prior to bondingThe most common type of aging is storage in water at temperatures from ambient to 100°C. This generally decreases bond strengths; but not to catastrophic values. A more exacting pre-test regime is thermal cycling. In some studies this caused a slightly greater reduction in bond strength than storage in water; but in other tests it resulted in total failure. As some testpieces have spontaneously debonded during thermal cycling, it seems sensible to include TC in any screening test of new materials. Mechanical cycling (fatigue) prior to testing has a very significant effect and the bond strength that can withstand 1,000,000 cycles can be one sixth of the bond strength in a simple monotonic test (tensile, shear or compression). Whereas simple monotonic tests provide a blunt instrument for eliminating poorly performing techniques their use for discriminating between established techniques is open to discussion.

Effects of metal primers on bonding of adhesive resin cement to noble alloys for porcelain fusing

This study evaluated the effects of metal primers on the bonding of adhesive resin to four pure metals (Au, Pd, Ag, Cu) and two noble alloys for porcelain fusing (high-gold and high-palladium content alloys). Bonding surface was polished with 600-grit silicon carbide paper and primed with one of the three metal primers (V-Primer, Metaltite, and M.L. Primer). Bonded specimens were fabricated by applying adhesive resin (Super-Bond C&B) on the primed surface. Shear bond strength (SBS) was determined both before and after thermocycling (4-60 degrees C for 2,000 cycles). The highest SBS values to each pure metal after thermocycling were 33.5 MPa for Au by M.L. Primer, 35.0 MPa for Ag by V-Primer, and 34.4 MPa for Cu by Metaltite. SBS to high-gold content alloy after thermocycling was 33.3 MPa by M.L. Primer. None of the primers was effective for pure Pd and high-palladium content alloy after thermocycling.

Model and data work together to reveal microscopic structures of materials

Microscopic compositional distributions are important in determining the bulk properties of materials.1 In one application dealing with anticorrosive primers for metals, the distributions of corrosion inhibitor and filler particles in a polymer matrix are major factors governing the degree of protection under corrosive conditions.2 In another application in the field of geosciences, knowledge of the microscopic distributions of mineral phases in various rock formations is critical in the oil and gas industry.3, 4 While the value of this structural information is self-evident, the experimental techniques available for obtaining it are generally costly and destructive to the sample. X-ray computed tomography (CT) has been used as a nondestructive method to probe the internal structures of materials. However, x-ray CT only gives a microscopic map of the radiation’s amplitude attenuation and phase shift and is usually inadequate to determine compositional distributions within heterogeneous materials by the usual image-rendering process.5 Data-constrained modeling (DCM) has extended the reach of x-ray CT techniques to more directly determine a sample’s material composition. By combining a generic model with sample-specific CT data taken under multiple x-ray beam conditions, we have shown that DCM can provide microscopic details of compositional distributions in a wide range of samples.6–9 DCM for predictive modeling of microscopic compositions is based on a number of assumptions. The total volume of a voxel (3D pixel) is the sum of the partial volumes of its constituent material compositions (including void). A voxel’s total x-ray interaction (including amplitude attenuation and phase shift) is the sum of the interactions of its constituent compositions. Its composition is also determined statistically by that of its Figure 1. DCM-software user interface with predicted compositional microstructure for a rock sample composed of quartz (blue) and calcite (red). The display corresponds to a sample size of 1.5 1 0.36mm3.

Evaluation of single liquid primers with organic sulfur compound for bonding between indirect composite material and silver-palladium-copper-gold alloy

The purpose of this study was to evaluate the effect of primers on bonding between a silver-palladium-copper-gold alloy and an indirect composite material. Cast disks were air-abraded with alumina, conditioned with one of five primers (Alloy Primer, Luna-Wing Primer, Metal Primer II, Metaltite, M.L. Primer), and bonded with a light-activated indirect composite. Shear bond strengths were determined after 20,000 times of thermocycling. The results showed that four of the primers, except the Luna-Wing Primer, were effective in enhancing the bond strength as compared with the unprimed control group. Of these four primers, Alloy Primer, Metal Primer II, and M.L. Primer exhibited significantly greater bond strengths. It can be concluded that the effectiveness of primers varies considerably according to the organic sulfur compounds added to the solvent, and that care must be taken in selecting priming agents for bonding the composite material and the silver-palladium-copper-gold alloy.

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

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. 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 x 5 x 1 mm(3)) from resin patterns. After casting, the plates were sandblasted with aluminum oxide (100 microm) 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. 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. The use of AP between alloy metal surfaces and resin cements did not increase the bond strength for most cementing systems evaluated.

In Vitro Tensile Bond Strength of Denture Repair Acrylic Resins to Primed Base Metal Alloys Using Two Different Processing Techniques

Approximately 38% of removable partial denture (RPD) failures involve fracture at the alloy/acrylic interface. Autopolymerizing resin is commonly used to repair RPDs. Poor chemical bonding of repair acrylic to base metal alloys can lead to microleakage and failure of the bond. Therefore, ideal repair techniques should provide a strong, adhesive bond. This investigation compared the tensile bond strength between cobalt-chromium (Super Cast, Pentron Laboratory Technologies, Llc., Wallingford, CT) and nickel-chromium (Rexalloy, Pentron Laboratory Technologies, Llc.) alloys and autopolymerized acrylic resin (Dentsply Repair Material, Dentsply Int, Inc, York, Pa) using three primers containing different functional monomers [UBar (UB), Sun Medical Co., Ltd., Shiga, Japan: Alloy Primer (AP) Kuraray Medical Inc., Okayama, Japan; and MR Bond (MRB) Tokyuyama Dental Corp., Tokyo, Japan] and two processing techniques (bench cure and pressure-pot cure). One hundred and twenty eight base metal alloy ingots were polished, air abraded, and ultrasonically cleaned. The control group was not primed. Specimens in the test groups were primed with one of the three metal primers. Autopolymerized acrylic resin material was bonded to the metal surfaces. Half the specimens were bench cured, and the other half were cured in a pressure pot. All specimens were stored in distilled water for 24 hours at 37 degrees C. The specimens were debonded under tension at a crosshead speed of 0.05 cm/min. The forces at which the bond failed were noted. Data were analyzed using ANOVA. Fisher's PLSD post hoc test was used to determine significant differences (p < 0.05). Failure modes of each specimen were evaluated under a dissecting microscope. Significant differences in bond strength were observed between combinations of primers, curing methods, and alloys. Primed sandblasted specimens that were pressure-pot-cured had significantly higher bond strengths than primed sandblasted bench-cured specimens. The pressure-pot-curing method had a significant effect on bond strength of all specimens except Co-Cr alloy primed with UB. The highest bond strength was observed for both Co-Cr and Ni-Cr alloys that were sandblasted, primed with MRB, and pressure-pot cured. Co-Cr alloys primed with UB had the lowest bond strength whether bench cured or pressure-pot cured. Primed specimens generally experienced cohesive bond failures within the primer or acrylic resin. Nonprimed specimens generally experienced adhesive bond failures at the resin/metal interface. Within the limitations of this study, MRB provided the highest bond strength to both Ni-Cr and Co-Cr alloys. Generally, bond strength improved significantly when specimens were primed. Pressure-pot curing, in most cases, resulted in higher bond strength than bench curing. The results of this in vitro study suggest that MRB metal primer can be used to increase bond strength of autopolymerized repair acrylic resin to base metal alloys. Curing autopolymerized acrylic under pressure potentially increases bond strength.

Durability of resin bonding to zirconia ceramic using different primers.

The purpose of this in vitro study was the evaluation of the bond strength and its durability to zirconia ceramic after using two phosphate monomer-containing primers. Plexiglas tubes filled with composite resin were bonded to zirconia ceramic disks (Cercon) which were air abraded (50 microm Al2O3 at 2.5 bar pressure) and ultrasonically cleaned in isopropanol for 3 min. Groups of 16 specimens each were bonded with Multilink Automix using either no primer (NO) or using a metal primer (AP: Alloy Primer, Kuraray) or a metal and zirconia primer (MZ: Metal/Zirconia Primer, Ivoclar Vivadent). Another group bonded with a phosphate monomer (MDP) containing resin (PF: Panavia F, Kuraray) served as control for an established bonding method to zirconia ceramic. Prior to tensile bond strength testing, subgroups of 8 bonded specimens were stored in distilled water (37 degrees C) for either 3 or 150 days. Additionally, the 150-day specimens were thermocycled (TC) between 5 degrees and 55 degrees 37,500 times. Statistical analyses were conducted with the Wilcoxon rank sum test. Without primer, the median initial bond strength of Multilink Automix to zirconia ceramic was relatively low (12.4 MPa). The primers improved the bond strength significantly (p <or= 0.05), increasing them to 38.5 MPa (Metal/Zirconia Primer) and 53.6 MPa (Alloy Primer). The Alloy Primer group did not differ significantly from the control group Panavia F with 51.8 MPa. After 150 days storage and TC, specimens without primer (NO) debonded spontaneously, while the other groups showed significantly reduced bond strengths ranging from 19.7 to 37.2 MPa. Using phosphate monomer-containing primers on air-abraded zirconia ceramic improves bonding to zirconia ceramic significantly.

Derivatization of Optically Transparent Materials with Diazonium Reagents for Spectroscopy of Buried Interfaces

This paper presents a method to derivatize a wide variety of substrate materials that are frequently used in spectroscopic characterizations with molecular layers through the reduction of aromatic diazonium reagents. The method relies on an ultrathin (5 nm) layer of a reactive metal (e.g., Ti or Al) deposited as a primer that subsequently mediates the reduction of aromatic diazonium reagents from acetonitrile solution. Following surface modification, the Ti can be oxidized to provide a passivated support surface. Raman, Infrared, UV-vis and X-ray photoelectron spectroscopic techniques are used to characterize the molecular layers on the metal primer surface. When a Ti primer layer is derivatized via diazonium reduction, the molecule is shown to be present on the ultrathin Ti layer on Au, Al, quartz, Si/SiO(x), glass, and polyethylene surfaces. For molecules bound to a Ti primer, the molecular layer was found to be stable to sonication in acetone or acetonitrile, a 1 h exposure to boiling water, and a 30 min exposure to 0.1 M acid or base. The approach also permits spectroscopic characterization of buried thin-film molecular layers on optically transparent substrates after deposition of thick top metal contacts.

Effect of metal primers on bond strength of resin cements to base metals

A strong and durable bond between a metal framework and a resin-based luting agent is desired. Metal primers have been shown to be very effective on noble alloys. However, there is insufficient information about their effect on base metals. The purpose of this study was to evaluate the effect of metal primers on the shear bond strength of resin cements to base metals. A total of 160 cast commercially pure titanium (CP Ti) and NiCr alloy (VeraBond II) disks were embedded in a polyvinyl chloride ring, and their surfaces were smoothed with silicon carbide papers (320, 400, and 600 grit) and airborne-particle abraded with 50-mum aluminum oxide. Specimens of each metal were divided into 4 groups (n=20), which received one of the following luting techniques: (1) Panavia F, (2) Alloy Primer plus Panavia F, (3) Bistite II DC, or (4) Metaltite plus Bistite II DC. Forty minutes after preparation, all specimens were stored in distilled water at 37 degrees C for 24 hours and then thermal cycled (1000 cycles, 5-55 degrees C). After thermal cycling, the specimens were stored in 37 degrees C distilled water for an additional 24 hours or 6 months before being tested in shear mode. Data (MPa) were analyzed using 3-way ANOVA and the post hoc Tukey test (alpha=.05). Each specimen was examined under an optical microscope (x30), and the failure mode was classified as adhesive, cohesive, or a combination of these. The only significant difference between the Panavia F and Alloy Primer plus Panavia F groups occurred in the NiCr alloy at 24 hours, at which point Panavia F demonstrated superior bond strength compared to Alloy Primer plus Panavia F (P<.001). The Bistite II DC and Metaltite plus Bistite II DC groups were not significantly different. The Bistite II DC and Metaltite plus Bistite II DC groups demonstrated significantly lower bond strength to CP Ti (P<.001) than the Panavia F and Alloy Primer plus Panavia F groups, and significantly lower bond strength to NiCr alloy (P<.001) than Panavia F. The Panavia F (P<.01) and Alloy Primer plus Panavia F groups' bond strength to titanium presented a significant increase (P<.001) in shear bond strength at 6 months. In general, the groups exhibited higher shear bond strength to CP Ti than to NiCr alloy (P<.01). The failure mode was 100% adhesive for all groups. The metal primers did not promote an increase in adhesive bonding of resin cements to NiCr alloy and to CP Ti. Water storage had no adverse effect on the shear bond strength of the groups. The shear bond strengths to titanium were significantly higher than those to the NiCr alloy.

Tensile bond strength of an adhesive resin cement to different alloys having various surface treatments

The ability of a resin cement to bond to a restorative alloy is critical for maximal crown retention to nonideal preparations. Surface treatment and metal type may have an important role in optimizing resin-to-metal strength. The purpose of this study was to examine the effect of surface pretreatment on the tensile strength of base and noble metals bonded using a conventional resin cement. Cylindrical plastic rods (9.5 mm in diameter), cast in base (Rexillium NBF) or noble metal (IPS d.SIGN 53), were divided into rods 10 mm in length (n=10-12). Specimens were heated in a porcelain furnace to create an oxide layer. Test specimens were further subjected to airborne-particle abrasion (50-microm Al(2)O(3) particles) alone or with the application of a metal primer (Alloy Primer). Similarly treated rod ends were joined using resin cement (RelyX ARC), thermocycled (x500, 5 degrees -55 degrees C) and stored (24 hours, 37 degrees C) before debonding using a universal testing machine. Debond strength and failure site were recorded. Rank-based ANOVA for unbalanced designs was used to test for significant interaction (alpha=.050). Each pair of treatments was compared separately for each metal (Bonferroni-adjusted significance level of .0083, overall error rate for comparisons, .05). The 2 metals were compared separately for each of the 3 treatments using an adjusted significance level of .017, maintaining an overall error rate of .05. A multinomial logit model was used to describe the effect of metal type and surface pretreatment on failure site location (alpha=.05). Interaction between metal type and surface pretreatment was significant for stress values (P=.019). Metal type did not significantly affect tensile bond strength for any of the compared surface pretreatments. Metal primer significantly improved tensile bond strength for each metal type. Most failures tended to occur as either adhesive or mixed in nature. Metal primer application significantly enhanced tensile bond strength to base and noble metal. No significant differences in tensile strength were found between alloys. Differences in failure site incidence were found to be related to metal type and surface pretreatment.