Metal Primer Research Articles

Measuring and comparing the shear bond strength of acrylic resin veneer to nickel –chromium alloy after different metal surface treatments

The bond strength of metal-resin interface of prosthesis is a key factor indetermining the serviceability of that prosthesis. The main objective of this study wasto determine the effect of different surface treatment on the shear bond strength of Ni-Cr alloy (CB-Blando 72 alloy) and heat cured acrylic veneer resin (Ivoclar Co.).Onehundred twenty eight disc shaped samples from base plate wax were prepared, thediameter of disc was (8mm×4.5mm).After casting the metal, the samples werecleaned, finished, and polished by silicon carbide abrasive paper with a grit size(600μm), and then the profilometer was used to determine the surface roughness ofthe samples (Ra) which ranged between (0.09-0.13μm). Then the samples weredivided into 2 categories ,each category contain (64)samples which also weresubdivided into 8 group ,the first category include (A, B, C, D, E, F, G, H) and thesecond category include (At, Bt, Ct, Dt, Et, Ft, Gt, Ht), according to the metal surfacetreatment which include :Group A, At: Received no treatment and serve as control.Group B, Bt: Received chemical treatment using chemical bonding agent (Metalprimer II).Group C, Ct: Received micromechanical treatment using air abrasion with 50μmAl2O3.Group D, Dt: Received micromechanical treatment using air abrasion with 50μmAl2O3 +metal primer IIGroup E, Et : Received micromechanical treatment using air abrasion with110μmAl2O3.Group F, Ft: Received micromechanical / chemical treatment using (airAbrasion110μm Al2O3 + metal primer II application).Group G ,Gt: Received micromechanical treatment using air abrasion 250μm Al2O3.Group H, Ht: Received micromechanical /chemical treatment using (air abrasion250μm Al2O3 +metal primer II).The acrylic was then prepared as round shape (8mm in diameter and 2mm inthickness) that was placed on the metal surface treatment; the acrylic was fabricated inthe same conventional way for construction veneer resin.For the specimens in the first category, the specimens were tested under drycondition, while in the second category; the specimens were tested after (24) hoursstorage in water room temperature (37˚C) and (1000 time) thermocycling. The shearbond strength was tested in instron universal testing machine.The results before and after thermocycling showed that the air abrasion with50μm Al2O3 plus metal primer II group gave the highest shear bond values, followedby air abrasion with 110μm Al2O3 plus metal primer II, followed by air abrasion with50μm Al2O3, followed by air abrasion with 250μm Al2O3 plus metal primer II,followed by air abrasion with 110μm Al2O3, followed by air abrasion with 250μm,followed by metal primer II group, and followed by untreated group.Also after thermocycling showead that the micromechanical/chemical treatment(air abrasion with Al2O3+metal primer II) gave the highest and more durable shearbond strength values than other groups

Bond strength of self-adhesive resin cement to base metal alloys having different surface treatments

This study aimed to assess and compare the shear bond strength of self-etch and self-adhesive resin cement to nickel-chromium-cobalt alloy with different surface treatments. In this in vitro study, a total of 120 disks were fabricated of VeraBond II base metal alloy. Specimens were divided into 15 groups of 8 based on the type of cement and surface treatment. The five surface treatments studied included sandblasting alone, application of Alloy Primer with and without sandblasting, and application of Metal Primer II with and without sandblasting. The three cement tested included Panavia F2.0, RelyX Unicem (RU), and G-Cem (GC). After receiving the respective surface treatments, the specimens were thermocycled for 1500 cycles and underwent shear bond strength testing. Data were analyzed using SPSS 20.0 and three-way analysis of variance. P values of the significant level of 0.05 were reported. The results exhibited that the mean bond strengths in sandblasted groups were higher than nonsandblasted one. These differences were significantly higher in the sandblasted groups of Panavia F2.0 and RU cement (P < 0.05). The mean bond strength values between GC and Panavia F2.0 were not statistically significant (P > 0.05). The highest bond strength was recorded for Panavia F2.0 with the surface treatment of both sandblasting and Metal Primer II. Based on the results, sandblasting improves the shear bond strength of self-etch and self-adhesive resin cement to base metal alloys. The best results can be achieved with a combination of sandblasting and metal primers. The performance of resin cement depends on to their chemical composition, not to the type of system.

ANALYSIS OF EFFECTS OF MECHANICAL LOADS, THERMAL FLUCTUATIONS AND CHEMICAL FACTORS ON THE BOND STRENGTH OF RESIN CEMENT TO TITANIUM AND CoCrMo ALLOYS IN IMPLANT SYSTEMS – IN VITRO STUDY

Introduction: Cements in the oral cavity are subjected to many factors affecting cement retention, the major ones being masticatory loads and thermal stress. The gold standard in cementing restorations in the contemporary implant prosthodontics are resin cements while their predisposition to the effects of oral cavity environment presents a major factor for the efficiency of dental implant treatment. Material and method: In the study, we used 40 test models made up of a combination of original components of the Nobel Biocare system (implant replica NobRplN and titanium suprastructure Easy abatement NP 0.75) and the restoration cast in CoCrMo alloy. The specimens were divided in 4 test groups with 10 specimens each. The specimens in each group were cemented with resin composite cement with or without using the metal primer. Group I – Multilink Implant, IvoclarVivadent, Liechtenstein, Group II – Multilink Implant, IvoclarVivadent, Liechtenstein + Monobond Plus, Group III G-CEM LinkAce®, Group IV - G-CEM LinkAce® + GC Metalprimer II. The specimens were stored in 100% relative humidity for 24 hours whereupon each group underwent 5 rounds of testing. The specimens were subjected to thermal and mechanical load cycling tests whose number reflected the period of simulation of the function in the oral cavity (unloaded specimens, 7 days of function, 3 months, 6 months and 12 months). The retention force was measured by the Universal testing machine. Results: The highest retention values of the resin composite cement were recorded during the initial tests, which then declined in the subsequent rounds of testing. The biggest fall was measured in the first week after the cementation, while the cross-comparison of the later rounds of testing did not show any statistically significant differences. The values of the retention force of resin composite cements 12 months after the cementation dropped by one third of the initial values. All recorded values were higher in the specimens with primer coating. Conclusion: Masticatory forces and temperature changes in the oral cavity reduced the retention values of resin cement, but its values after 12 months of function were still high and provided stability and retention of the restoration in function. The usage of metal primer had a significant effect on retention force values at all levels of testing.

Effect of Sulfur-Containing Primers for Noble Metals on the Bond Strength of Self-Cured Acrylic Resin.

This study investigated the effect of sulfur-containing primers for noble metals on the shear bond strength of self-cured acrylic resin after thermal cycling (TC). Four pure metals (Au, Ag, Cu, and Pd) and type IV Au alloy were either untreated, or treated with one of the five sulfur-containing metal primers (V-Primer, Metaltite, Alloy Primer, Metal Link Primer, and Metal Primer Z). Afterwards, a brass ring was placed on the metal surface and filled with self-cured acrylic resin (n = 10). The bond strengths were measured after 24 h (TC0) and after 2000 thermal cycles at 4–60 °C (TC2000). Three-way ANOVA and Tukey compromise post hoc tests were used to analyze the data (α = 0.05). All of the sulfur-containing primers significantly improved the resin bond strength as compared to that of the non-primed group at TC0 regardless of the metal type (p < 0.05). However, at TC2000, the bond strengths between the resin and the five metals significantly decreased with respect to the values obtained at TC0 regardless of the primer (p < 0.05). The sulfur-containing metal primers, except for Metal Link Primer, were found to be more effective for improving the bond strength between the self-cured acrylic resin and Ag as compared to the other three pure metals (p < 0.05). The bond strengths between the resin and Au and type IV Au alloy at TC2000 were the highest ones when Metal Primer Z was used.

Effect of Metal Primers on Bond Strength of a Composite Resin to Nickel-Chrome Metal Alloy.

This study evaluated the effects of three metal primers and one multi-mode adhesive system on the shear bond strength (SBS) of a flowable composite resin to nickel-chrome metal alloy (Ni-Cr). Ninety plates were cast from Ni-Cr and divided in nine groups (n=10). The surfaces were sandblasted with Al2O3 and primed with three adhesive primers: Alloy Primer (AP), Universal Primer (TP) and RelyX Ceramic Primer (CP), and a multi-mode adhesive (Scotchbond Universal, SU). The Adper Single Bond Plus (SB) and SU adhesives were also combined with adhesive primers. Control group did not have any surface treatment. The groups were: AP, AP+SB, AP+SU, TP+SB, TP+SU, CP+SB, CP+SU and SU. Composite cylinders were built on alloy surface. After 24 h, half the specimens were subjected to SBS and the other half to thermal cycling before testing. Data were analyzed by two-way ANOVA and Tukey's test (a=0.05). Failure modes were assessed by SEM observation. Higher SBS were obtained with AP and TP combined with adhesives at 24 h and the lowest one for control group. Thermocycling reduced SBS for AP, CP+SU and SU. Combination between TP and SU resulted in the highest SBS after the thermocycling. TP groups showed all types of failures and high incidence of mixed failures. The use of AP and UP metal primers before application of SU and SB adhesive systems increased the SBS of composite to Ni-Cr. These combinations between metal primers and adhesives had the highest SBS after thermocycling.

Comparison of the effectiveness of Tokuyama and GC II metal primer on the bond strength of acrylic resins to Ti-6Al-7Nb.

Statement of Problem:Because of the toxicity of vanadium in Ti-6Al-4V alloy, next generation of titanium alloys is proposed to focus on niobium-containing alloy, but for clinical applications, it is crucial for this alloy to bond with acrylic resins with or without the use of primers. However, literature was lacking about the effect of primers on bonding of autopolymerizing resins to Ti-6Al-7Nb.Objectives:To evaluate the effect of different metal primers on the shear bond strength of acrylic resin to Ti-6Al-7Nb.Materials and Methods:A total of 30 dis-shaped wax patterns (10 mm in diameter and 2 mm thickness) were prepared and casted using Ti-6Al-7Nb. After casting, the disk surfaces were finished with abrasive paper under water. Specimens were equally divided into three groups on the basis of the use of primer: metal primer (GC II metal primer) (Group 1), Universal Tokuyama primer (Group 2), no primer (Group 3). Tape of 50 μm thickness was applied on each of the specimens. Then, self-cure acrylic resin was mixed and applied on the center part of the tape, on which Bernouilles tube was placed. The tensile bond strength was measured with a universal testing machine. The data were obtained for all the specimens and analyzed using Statistical Package for Social Sciences version 17.0 at a statistically significance level of <0.05.Results:Mean tensile force was maximum for Group 2 (28.58 ± 39.40 N) and minimum for control Group 3 (6.24 ± 10.97 N), thereby showing a significant inter-group difference (P < 0.001). On applying post hoc test (Tukey HSD), both the Group 1 and Group 2 showed a statistically significant difference as compared to control Group 3; however, the difference between two experimental groups was not statistically significant (P > 0.05).Conclusions:Tokuyama primer and GC II metal primer had a significant effect on improving the bond strength between autopolymerizing denture base resin and Ti-6Al-7Nb.

The effect of phosphoric and phosphonic acid primers on bone cement bond strength to total hip stem alloys

Aseptic loosening at alloy-cement interfaces constitutes a main failure mechanism of cemented total hip replacements (THR). As a potential solution we investigated the effect of metal primers containing phosphoric and phosphonic acid on shear bond strength (SBS) of bone cement to THR alloys (CoCrMo, TiAlNb) and pure tin (Sn) substrates (20×8×3 mm). Metal surfaces were modified by polishing or Al2O3 blasting and primer application. Substrates without primer treatment served as references. Cylindrical cement pins (Ø 5mm) were polymerised onto substrate surfaces and aging (1, 5, 14 and 150 days) was simulated in aqueous NaCl solution (0.9%) before SBS determination and failure mode evaluation.Regardless of surface roughness and aging time, SBS for THR alloys and Sn was always significantly higher with primer treatment. Compared to untreated reference specimens (≤0.2MPa) SBS values increased even up to 350 fold (TiAlNb, 14 days) or 400 fold (CoCrMo, 5 days). In general, the phosphoric acid containing primer revealed significant higher SBS values on THR alloys compared to the phosphonic acid containing one. Al2O3 blasted specimens showed generally higher SBS values than polished ones with the exception of Sn which showed high SBS values in general. With primer treatment on polished Sn a significant reduction of SBS could not be detected even up to 150 days, whereas THR alloys showed only an SBS improvement in the short term (≤14 days). A NaCl-pitting corrosion probably led to an increasing and durable SBS on polished Sn surfaces over time.Compared to modern THR in clinical practice that shows survival rates of 10, 15, 20 or more years, the receivable bond strength enhancements described in this study appeared to be very short. The improved SBS on THR alloys lasted only a few days before it was lost again. In contrast, the phosphoric acid primer treatment of polished Sn appeared to be very promising and may play a key role in further investigations dealing with the prevention of the stem-cement debonding in THR.

Development of zinc ferrocyanide ion exchange compounds for corrosion-inhibiting and sensing pigments

The fabrication and application of zinc ferrocyanide ion exchange compounds for use as inhibiting and sensing pigments in protective paints and primers for metals and alloys are described in this paper. A distinctive property of these ferrocyanide pigments is an ability to store corrosion inhibitors and then release them when needed by an ion exchange process. The exchange process is triggered when moisture containing Na+ and K+ ions contacts inhibitor particles embedded in an organic coating. The exchange kinetics were studied by measuring the concentration of released zinc ions in the solution with inductively coupled plasma. The inhibitor storage capacity can be as high as 200 meq/100 g, and it is much higher than that found in other reported ion exchange compounds. Furthermore, structure changes from non-crystalline to crystalline, upon exchange with alkaline ions, can be detected by x-ray diffraction, providing an important indication of activation of the corrosion protection. This is a form of corrosion sensing. The inhibition performance of zinc ferrocyanide in the coating was examined by salt spray tests and electrochemical impedance spectroscopy, and both tests showed that zinc ferrocyanide could provide good protection on aluminum alloy 2024.

ANALYSIS OF EFFECTS OF MECHANICAL LOADS, THERMAL FLUCTUATIONS AND CHEMICAL FACTORS ON THE BOND STRENGTH OF RESIN CEMENT TO TITANIUM AND CoCrMo ALLOYS IN IMPLANT SYSTEMS – IN VITRO STUDY

Introduction: Cements in the oral cavity are subjected to many factors affecting cement retention, the major ones being masticatory loads and thermal stress. The gold standard in cementing restorations in the contemporary implant prosthodontics are resin cements while their predisposition to the effects of oral cavity environment presents a major factor for the efficiency of dental implant treatment. Material and method: In the study, we used 40 test models made up of a combination of original components of the Nobel Biocare system (implant replica NobRplN and titanium suprastructure Easy abatement NP 0.75) and the restoration cast in CoCrMo alloy. The specimens were divided in 4 test groups with 10 specimens each. The specimens in each group were cemented with resin composite cement with or without using the metal primer. Group I – Multilink Implant, IvoclarVivadent, Liechtenstein, Group II – Multilink Implant, IvoclarVivadent, Liechtenstein + Monobond Plus, Group III G-CEM LinkAce®, Group IV - G-CEM LinkAce® + GC Metalprimer II. The specimens were stored in 100% relative humidity for 24 hours whereupon each group underwent 5 rounds of testing. The specimens were subjected to thermal and mechanical load cycling tests whose number reflected the period of simulation of the function in the oral cavity (unloaded specimens, 7 days of function, 3 months, 6 months and 12 months). The retention force was measured by the Universal testing machine. Results: The highest retention values of the resin composite cement were recorded during the initial tests, which then declined in the subsequent rounds of testing. The biggest fall was measured in the first week after the cementation, while the cross-comparison of the later rounds of testing did not show any statistically significant differences. The values of the retention force of resin composite cements 12 months after the cementation dropped by one third of the initial values. All recorded values were higher in the specimens with primer coating. Conclusion: Masticatory forces and temperature changes in the oral cavity reduced the retention values of resin cement, but its values after 12 months of function were still high and provided stability and retention of the restoration in function. The usage of metal primer had a significant effect on retention force values at all levels of testing.

Porosity of maxillofacial silicone elastomers and microleakage pattern of the commercially pure Ti-silicone elastomer interface after hydrothermal cycling

Statement of problemDelamination of the maxillofacial silicone elastomer away from the commercially pure titanium (cpTi)-encapsulated magnets affects the long-term performance of the facial restoration. PurposeThe purposes of this in vitro study were to investigate the interfacial microleakage patterns of 2 maxillofacial silicone elastomers with cpTi when 3 different primers were used and to evaluate the porosity of the 2 elastomers tested. Material and methodsTo test the interfacial microleakage patterns of the 2 elastomers MDX4-4210 (EL1) and A-2006 (EL2) with cpTi when 3 metal primers, A-304 (PR1), A-320 bonding enhancer (PR2), Super-Bond C&B monomer (PR3), and ethyl-cyanoacrylate (Super Glue) were used, the bonded interfaces were observed using reflected light microscopy, and the percentage of the linear extent of leakage along the interface (%microleakage) was measured. High-resolution x-ray computed microtomography scanning was used to investigate the percentage of void volume fraction (%VF) for both silicone EL1 and EL2. The data were analyzed with 2-way ANOVA and post hoc tests (α=.05). ResultsNo statistically significant differences were found among the percentages of PR1, PR2, and PR3 microleakage, whereas ethyl-cyanoacrylate showed a statistically significant higher percentage of microleakage than either of the silicone elastomers (P<.001). EL1 medical grade elastomer groups have always had a statistically significantly higher percentage of microleakage than the EL2 platinum silicone elastomer groups (P<.001). For both elastomers, no statistically significant differences were found in %VF (P=.056). ConclusionsDifferences in mechanical properties, chemical composition, and manipulations during handling of the maxillofacial silicone elastomers can affect the linear microleakage along the cpTi-silicone elastomer bonding interface and the porosity of the silicone elastomer.

The Effect of Artificial Aging on The Bond Strength of Heat-activated Acrylic Resin to Surface-treated Nickel-chromium-beryllium Alloy.

PurposeThe debonding load of heat-activated polymethylmethacrylate (PMMA) denture base resin material to a nickel-chromium-beryllium (Ni-Cr-Be) alloy conditioned by three different surface treatments and utilizing two different commercial bonding systems was investigated.Materials and MethodsDenture resin (Lucitone-199) was bonded to Ni-Cr-Be alloy specimens treated with Metal Primer II, the Rocatec system with opaquer and the Rocatec system without opaquer. Denture base resin specimens bonded to non-treated sandblasted Ni-Cr-Be alloy were used as controls. Twenty samples for each treatment condition (80 specimens) were tested. The 80 specimens were divided into two categories, thermocycled and non-thermocycled, containing four groups of ten specimens each. The non-thermocycled specimens were tested after 48 hours’ storage in room temperature water. The thermocycled specimens were tested after 2,000 cycles in 4°C and 55°C water baths. The debonding load was calculated in Newtons (N), and collected data were subjected by non parametric test Kruskal-Wallis One Way Analysis of Variance on Ranks and Dunn’s post hoc test at the α = 0.05.ResultsThe Metal Primer II and Rocatec system without opaquer groups produced significantly higher bond strengths (119.9 and 67.6 N), respectively, than did the sandblasted and Rocatec system with opaquer groups, where the bond strengths were 2.6 N and 0 N, respectively. The Metal Primer II was significantly different from all other groups (P<0.05). The bond strengths of all groups were significantly decreased (P<0.05) after thermocycling. ConclusionsAlthough thermocycling had a detrimental effect on the debonding load of all surface treatments tested, the Metal Primer II system provided higher values among all bonding systems tested, before and after thermocycling.

Effects of two metal primers on the shear bond strength of orthodontic molar tubes bonded to silver amalgam restorations of different dimensions

The aim of this study was to evaluate the shear bond strength (SBS) of orthodontic molar tubes bonded to amalgam restorations and enamel with four different area ratios, with and without the use of various metal primers. One hundred and fifty-six sound lower first molars were divided into five groups; control group (CG;n = 12) then divided into three subgroups: A, B, and C. Class V buccal amalgam restorations consisting of 25%(G1), 50%(G2), 75%(G3), and 100%(G4) of the basal areas of the molar tubes. Transbond XT Primer (TXTP;subgroup A), Alloy Primer (AP;subgroup B) and Reliance Metal Primer (RMP;subgroup C) (n = 12). Transbond XT was used as an adhesive material in all groups. Thermocycling was as 5 –55 °C, 1000 cycles. Data were analysed by one-way ANOVA and post hoc least significant difference tests (p < 0.05). Bond failure sites were classified using a modified Adhesive Remnant Index (ARI) system. SBS did not differ significantly among the three intermediate adhesives in subgroups of groups 1, 2, or 3 (p > 0.05); however, SBS was significantly higher in groups 4B and 4C than in group 4A (p < 0.05). Mean SBSs of groups 1 and 2 were significantly higher than others (p < 0.05). Mean SBS of group 3 was higher than that of group 4, but lower than that of the other groups. For ARI, significant relationships between CG and the intermediate adhesive groups were found (p < 0.05). Application of metal primers, such as AP or RMP, to sandblasted amalgam adjacent to etched enamel (25, 50, and 75%) did not improve bond strength significantly compared with the application of TXTP to amalgam and enamel.

Preliminary analysis of the possibility of preparing PVB/IF-WS2 composites. Effect of nanoparticles addition on thermal and rheological behavior of PVB

A possibility of using inorganic fullerene-like tungsten disulfide, IF-WS2, nanoparticles as a filler in poly (vinyl butyral), PVB, for improving its thermal and rheological properties is examined. PVB is a thermoplastic polymer with excellent properties, widely used: in ballistic protection, for protection of safety glass, in metal primers and coatings, temporary binders. Two different molecular weights of PVB were previously examined in this research: Mowital B60H and B75H. Both grades of PVB were dissolved in different solvents: ethanol and 2-propanol. Thin films were prepared by solvent casting technique. The glass transition temperature (Tg) of the tested samples was determined using differential scanning calorimetry (DSC), at three different heating rates (5°C/min, 10°C/min and 20°C/min). After choosing a solvent and PVB grade, IF-WS2 nanoparticles were added to PVB solutions and dispersed by ultrasonic irradiation. Compatibility, i.e. interaction of IF-WS2 with the dissolved PVB was examined by microcalorimetry method. The nanoparticles dispersion and deagglomeration in matrix of PVB was analyzed by scanning electron microscope (SEM). The effect of IF-WS2 on rheological properties of the chosen samples has been examined using Dynamic Mechanical Thermal Analysis (DMTA), observing storage modulus, loss modulus and the loss factor as functions of temperature for the tested composites.

The effect of dental metal primer on the bond strength between oxidation heat-treated gold-silver-palladium alloys and MMA-TBBO resin

The effect of dental metal primer on the bond strength between oxidation heat-treated gold-silver-palladium alloys and MMA-TBBO resin

An investigation into the effects of metal primer and surface topography on the tensile bond strength between cobalt chromium alloy and composite resin

This study examined the influence of surface preparation and metal primer on the tensile bond strength between cobalt chromium alloy and composite resin. The bond strength between 168 cobalt chromium alloy dumb-bells with one of three test surfaces (beaded, machined or sandblasted) to composite resin were tested. Half of each group were treated with metal primer. The weakest bond strength was produced by the unprimed machined surface, many specimens failing before testing. The metal primer increased the bond strengths of all groups tested. The greatest bond strengths were achieved with the primed beaded and sandblasted surfaces. Within the limits of the study it has been shown that the surface preparation of the cobalt-chromium alloy did influence tensile bond strengths with composite resin and Metal Primer II increased the tensile bond strengths for all groups tested. The sandblasted surface treated with Metal Primer II is recommended for the bonding of composite resin to cobalt chromium alloy.

The Effect of Novel Mercapto Silane Systems on Resin Bond Strength to Dental Noble Metal Alloys.

Self-assembled monolayers of thiols (RSH), which are key elements in nanoscience and nanotechnology, have been used to link a range of materials to planar gold surfaces or gold nanoparticles. In this study, the adhesive performance of mercapto silane systems to dental noble metal alloys was evaluated in vitro and compared with that of commercial dental primers. Dental gold-palladium-platinum (Au-Pd-Pt), gold-palladium-silver (Au-Pd-Ag), and palladium-silver (Pd-Ag) alloys were used as the bonding substrates after air-abrasion (sandblasting). One of the following primers was applied to each alloy: (1) no primer treatment (control), (2) three commer- cial primers: V-Primer, Metal Primer II, and M.L. Primer, and (3) two experimental silane primer systems: 2-step application with 3-mercaptopropyltrimethoxysilane (SPS) (1.0 wt%) and then 3-methacryloxypropyltrimethoxysilane (MPS) (1.0 wt%), and a silane blend consisting of SPS and MPS (both 1.0 wt%). Composite resin cylinders with a diameter of 2.38 mm were bonded to the surfaces and irradiated for 40 sec using a curing light. After storage in water at 37 °C for 24 h, all the bonded specimens were thermocycled 5000 times before the shear bond strength test. Regardless of the alloy type, the mercapto silane systems (both the 2-step and blend systems) consistently showed superior bonding performance than the commercial primers. Contact angle analysis of the primed surfaces indicated that higher resin bond strengths were produced on more hydrophilic alloy surfaces. These novel mercapto silane systems are a promising alternative for improving resin bonding to dental noble metal alloys.

Recent Advances in Synthesis of Waterborne Polyurethane and Their Application in Water-based Ink: A Review

Over the last few years, waterborne polyurethane (WPU) was applied to various fibers, adhesives, primers for metals, caulking materials, emulsion polymerization media, paint additives, defoamers, associate thickeners, pigment pastes, textile dyes and biomaterials, resulting in the increasing enthusiasm of researchers to design and synthesize novel WPU with unique properties. Thus, various processes and raw materials have been developed to prepare WPU. This review gives an overview on the developments of WPU mainly derived from novel polyols, analyzes the potential application in water-based inks and presents the probable future research area about water-based inks. Notably, the poly(e-caprolactone) and poly(lactic acid) are the versatile materials used in WPU synthesis and supply the potential special performance for preparing WPU. Meanwhile, addition–fragmentation chain transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP) processes provide an opportunity to control the chain sequence of WPU and obtain products with the desired performance.

Evaluation of experimental phosphate and sulfur-based primer bonding to metal casting alloys

The aim of this study was to evaluate the effect of three experimental primers prepared with synthesized phosphorous and sulfur monomers (HEMA-P, ETMA and the mixture of HEMA-P/ETMA) on bonding to nickel–chromium (NiCr), silver–palladium (AgPd) and silver–gold (AgAu) metal alloys. The specimens were treated with experimental primers: HEMA-P, ETMA, HEMA-P/ETMA and Alloy Primer (Kuraray Noritake Dental Inc., Okayama, Japan) was used as commercial reference. Resin cement cylinders were built-up after application of tested primers on different alloy surfaces. Samples were stored in distilled water at 37°C for 24h before being subjected to shear bond tests using a mechanical testing machine. Shear bond strength (SBS) was recorded in MPa. Failure modes were classified under magnification as adhesive and mixed failure. Data were submitted to a two-way ANOVA and Student–Newman–Keuls׳ test. The statistically highest shear bond strength was observed with commercial primer to the AgPd alloy while the lowest value was shown with commercially available primers and experimental HEMA-P/ETMA to the NiCr alloy (p<0.05).There was a predominance of adhesive failure, with the exception of commercially available primer, for which mixed failures were predominant. It could be concluded that formulations of metal primers containing HEMA-P or ETMA primers should be considered for use in the bonding protocol of NiCr alloys.

Comparative evaluation of effect of metal primer and sandblasting on the shear bond strength between heat cured acrylic denture base resin and cobalt-chromium alloy: An in vitro study.

Aims:The aim of this study was to evaluate the effect of metal primers and sandblasting on the shear bond strength (SBS) of heat cured acrylic denture base resin to cobalt-chromium (Co-Cr) alloy.Materials and Methods:A total number of 40 disk shaped wax patterns (10 mm in diameter and 2 mm in thickness) were cast in Co-Cr alloy. Samples were divided into 4 groups depending on the surface treatment received. Group 1: No surface treatment was done and acts as control group. Group 2: Only sandblasting was done. Group 3: Only metal primer was applied. Group 4: Both metal primer and sandblasting were done. After surface treatment samples had been tested in Universal Testing Machine at crosshead speed of 0.5 mm/min in shear mode and scanning, electron microscope evaluation was done to observe the mode of failure.Statistical Analysis:All the observations obtained were analyzed statistically using software SPSS version 17; one-way analysis of variance (ANOVA) and post-hoc Tukey test were applied.Results:The one-way ANOVA indicated that SBS values varied according to type of surface treatment done. The SBS was highest (18.70 ± 1.2 MPa) when both sandblasting and metal primer was done when compared with no surface treatment (2.59 ± 0.32 MPa).Conclusions:It could be concluded that the use of metal primers along with sandblasting significantly improves the bonding of heat cured acrylic denture base resin with the Co-Cr alloy.

Effect of Surface Treatments on the Bond Strength of Veneering Ceramic to Zirconia

The purpose of this study was to evaluate the effect of different surface treatments on the bond strength of veneering ceramic to zirconia. Square (15 mm x 10 mm x 2 mm) zirconia specimens (n=18) received one of the following surface treatments: Group 1, sandblasting; Group 2, Clearfil ceramic primer application; Group 3, grinding; Group 4, alloy primer application; and Group 5, RelyX ceramic primer application. The zirconia core specimens were layered with a veneering porcelain (5 mm x 3 mm x 3 mm). Mean shear bond strength values (MPa) were calculated. Data were analyzed with one-way ANOVA and Tukey's post hoc pairwise comparisons (α=0.05). Fractured surfaces of the specimens were examined with scanning electron microscope (SEM). This study showed that bond strengths of the metal primer-treated zirconia specimens (Group 4) were significantly higher than those of the other paired groups. The application of metal primer affected the specimens' failure mode. SEM analysis demonstrated that Group 4 had mainly cohesive fractures, while the other groups showed approximately equal levels of adhesive and mixed fracture types. The mean and SD values for shear bond strengths ranged from 8.90 ± 3.42 MPa (Group 2) to 19.74 ± 4.96 MPa (Group 4). In conclusion, the application of a metal primer to a zirconia core increased the bond strength of veneering ceramics. The use of chemical agents to improve the strength of the zirconia core's bond to veneering ceramic may have more benefits than the use of mechanical pretreatments.