Zirconia Primer Research Articles

The potential of novel primers and universal adhesives to bond to zirconia

ObjectivesTo investigate the adhesive potential of novel zirconia primers and universal adhesives to surface-treated zirconia substrates. MethodsZirconia bars were manufactured (3.0mm×3.0mm×9.0mm) and treated as follows: no treatment (C); air abrasion with 35μm alumina particles (S); air abrasion with 30μm silica particles using one of two systems (Rocatec or SilJet) and; glazing (G). Groups C and S were subsequentially treated with one of the following primers or adhesives: ZP (Z-Prime Plus), AZ (AZ Primer); MP (Monobond Plus); SU (ScotchBond Universal) and; EA (an Experimental Adhesive). Groups Rocatec and SilJet were silanized prior to cementation. Samples form group G were further etched and silanized. Bars were cemented (Multilink) onto bars of a silicate-based ceramic (3.0mm×3.0mm×9.0mm) at 90° angle, thermocycled (2.500 cycles, 5–55°C, 30s dwell time), and tested in tensile strength test. Failure analysis was performed on fractured specimens to measure the bonding area and crack origin. ResultsSpecimens from group C did not survive thermocycling, while CMP, CSU and CEA groups survived thermocycling but rendered low values of bond strength. All primers presented a better bond performance after air abrasion with Al2O3 particles. SilJet was similar to Rocatec, both presenting the best bond strength results, along with SMP, SSU and CEA. G promoted intermediate bond strength values. Failure mode was predominately adhesive on zirconia surface combined to cohesive of the luting agent. ConclusionsUniversal adhesives (MP, SU, EA) may be a considerable alternative for bonding to zirconia, but air abrasion is still previously required. Air abrasion with silica particles followed by silane application also presented high bond strength values.

Thermal silicatization: A new approach for bonding to zirconia ceramics

This study introduces a novel surface treatment (thermal silicatization) for bonding to zirconia ceramics. The method is based on the application of a solution containing silane, distilled water, and absolute ethanol, followed by heat treatment at 150°C for 1h and 600°C for 2h for deposition of a reactive siloxane network on the zirconia surface. The thermal silicatization was compared with traditional coupling agents for ceramic bonding (silane, zirconia primer, and/or adhesive), evaluating the shear bond strength of a dual-cured resin luting agent to yttria-stabilized zirconia. For the thermal silicatization method, two groups were tested: one group with silane applied to the ceramic (Sit) and another group with the application of silane and adhesive (SitA). Data were analyzed by ANOVA on ranks and Dunn's test (5%). The zirconia primer yielded higher bond strength compared with silane and/or adhesive. The combination of zirconia primer and adhesive generated higher bond strength than the primer alone. The group Sit showed higher bond strength than most of the groups while the bond strength of SitA had higher bond strength than all other groups. Deposition of a silicate layer on the zirconia surface was confirmed by x-ray energy dispersive spectroscopy. In conclusion, the proposed thermal silicatization method might promote the bonding of resin luting agents to dental zirconia ceramics. The proposed method is simpler and more cost-effective compared to other methods described in the literature as it could applied to the internal surface of zirconia frameworks using the same sintering protocol of the veneering ceramic.

Effect of incorporating BisGMA resin on the bonding properties of silane and zirconia primers

Some silane primers and some zirconia primers contain extra resins such as bisphenol A glycol dimethacrylate (BisGMA) in their formulations for better wetting. No studies exist on the bonding properties of zirconia and silane primers, which contain extra resins. The purpose of this study was to investigate the effect of incorporating BisGMA resin on the bonding properties of silane and zirconia primers. Silica-base lithium disilicate was etched and treated with BisGMA-incorporated Porcelain Primer, unmodified Porcelain Primer, or resin-containing Kerr Silane. Zirconia ceramic was airborne-particle abraded and treated with BisGMA-incorporated Monobond Plus, unmodified Monobond Plus, or BisGMA-containing ZPrime Plus. After primer treatment and cleaning with ethanol, the contact angles were measured to determine surface change (n=10). Shear bond strength tests were also performed to measure the adhesion strength between resin cements and ceramic surfaces (n=10). Data were statistically analyzed by 1-way ANOVA followed by the Tukey multiple comparison as a post hoc test (significance level .05). The incorporation of BisGMA resin did not significantly influence the bond strength or contact angle of the zirconia primer (P>.05), but it did significantly reduce those of the silane primer (P<.05). Resin-containing Kerr Silane (22 degrees, 23 MPa) had a similar contact angle and higher bond strength than the control (21 degrees, 18 MPa), but lower than Porcelain Primer (88 degrees, 34 MPa). Resin-containing ZPrime Plus (75 degrees, 29 MPa) had a similar contact angle and higher bond strength than both Monobond Plus (74 degrees, 18 MPa) and the control (15 degrees, 4 MPa). The addition of BisGMA resin significantly inhibited the efficacy of silane-containing porcelain primers but did not affect that of phosphate-containing zirconia primers.

An In Vitro Comparison of Shear Bond Strength of Zirconia to Enamel Using Different Surface Treatments

The purpose of this in vitro study was to compare the shear bond strength of an airborne-particle abraded zirconia, an acid-etched zirconia (Piranha solution), an Alloy Primer treated zirconia, and a silaned zirconia to enamel, all bonded with a phosphate-methacrylate resin luting agent. Seventy extracted intact human molars were collected, cleaned, and mounted in autopolymerizing acrylic resin, with the experimental surface of the teeth exposed. The specimens were randomly divided into seven groups of zirconia specimens (4 mm diameter, 2 mm thick). Group 1: Airborne-particle abrasion; group 2: Airborne-particle abrasion and Z-PRIME Plus; group 3: Airborne-particle abrasion and alloy primer; group 4: Piranha solution 7:1; group 5: Piranha solution 7:1 and Z-PRIME Plus; group 6: Piranha solution 7:1 and Alloy primer; group 7: CoJet and silane. All specimens were luted with a phosphate-methacrylate resin luting agent (Panavia F2.0) and stored in distilled water for 1 day, then thermocycled (5°C and 55°C) for 500 cycles and tested for shear bond strength (SBS), measured in MPa, with a universal testing machine at a 0.55 mm/min crosshead speed. All specimens were inspected under a scanning electron microscope to determine mode of failure. The mean values and standard deviations of all specimens were calculated for each group. A one-way ANOVA was performed, and multiple pairwise comparisons were then completed with post hoc Tukey test (alpha = 0.05). The airborne-particle abrasion and Z-PRIME Plus group resulted in a significantly higher SBS than the other groups (21.11 ± 6.32 MPa) (p < 0.001). The CoJet and silane group (15.99 ± 8.92 MPa) and airborne-particle abrasion and alloy primer group (11.07 ± 4.34 MPa) showed high shear bond strength but not statistically significant from the airborne-particle abrasion group (14.23 ± 5.68 MPa). Failure mode was predominately mixed in groups 1, 2, 3, and 7 with islands of retained resin on the zirconia and enamel surfaces; however, groups 4, 5, and 6 showed mostly adhesive failures, which left the zirconia surface free of the adhesive materials. No cohesive failures of the substrates (ceramic, resin, or enamel) were observed. Airborne-particle abrasion followed by the application of a zirconia primer produced the highest bond strength to enamel. Therefore, it can be recommended as a promising surface treatment method to achieve a durable bond to densely sintered zirconia ceramics.

Intraoral treatment of veneering porcelain chipping of fixed dental restorations: A review and clinical application

<h3>Background</h3> Every dental ceramic system can experience failure of the veneering porcelain. However, the increasing popularity of all-ceramic crowns and fixed dental prostheses (FDPs) seems to have led to an increasing need to repair chipped veneering porcelain. <h3>Objectives</h3> The authors compared different methods to repair fractured ceramic restorations (porcelain-fused-to-metal and all-ceramic) and explain the basic principles of adhesion in these systems. They also evaluated the frequency and causes of failure in dental ceramic systems. <h3>Methods</h3> This review is based on the results of PubMed and Google Scholar searches, as well as on a hand search of the scientific literature, resulting in 300 articles from 1977 to 2012. The authors used multiple key words (ceramic, repair, bonding, hydrofluoric acid, air abrasion, silane, phosphates, silicon dioxide) and different strategies (connecting different key words with OR, NOR and AND and truncation of the stem of words) to search the databases. <h3>Results</h3> Because of differences in the material composition of ceramic systems (composed of metal, alumina or zirconia, glass-ceramics and feldspathic ceramics), different treatments are required for the exposed material surfaces after chipping. Use of hydrofluoric acid etching, air abrasion, tribochemical coating, silanization and metal primers or zirconia primers seem to be the most successful conditioning methods for durable bonding and repair. <h3>Conclusions and Clinical Implications</h3> Intraoral repair of a restoration offers a satisfying option for the patient when the restoration cannot be removed or replaced. Its success depends largely on the conditioning methods used for the fractured surfaces.

In vitro short-term bonding performance of zirconia treated with hot acid etching and primer conditioning etching and primer conditioning

This study aimed to investigate and compare the resin bond strengths of zirconia conditioned as follows: alumina sandblasting; alumina sandblasting+application of 10-MDP-containing primer; alumina sandblasting+application of Z-Prime Plus or Metal/Zirconia Primer (new zirconia primers); tribochemical silica coating+silanization; hot acid etching in three different combinations [H2SO4/(NH4)2SO4, HF/HNO3, H2SO4/HF/HNO3]+application of 10-MDP-containing primer. Shear bond strengths (SBS) after water storage for 24 h and 40 days were measured to assess resin bonding performance. Surface and chemical properties of conditioned zirconia surfaces and primers were characterized using scanning electron microscopy, energy dispersive X-ray spectrometry, Fourier transform infrared spectroscopy, and atomic force microscopy. Surface roughness ranked in descending order was: hot acid etching > tribochemical silica coating > alumina sandblasting. Combination of tribochemical silica coating and silanization showed the highest initial SBS (12.46±2.13 MPa) (P<0.01). Etching with H2SO4/(NH4)2SO4 (13.15±3.24 MPa) and HF/HNO3 (13.48±2.15 MPa) showed significantly better bond durability (P<0.01). Hot acid etching seemed to be a promising surface roughening treatment to improve resin-zirconia bonding.

Effect of various intraoral repair systems on the shear bond strength of composite resin to zirconia

PURPOSEThis study compared the effect of three intraoral repair systems on the bond strength between composite resin and zirconia core.MATERIALS AND METHODSThirty zirconia specimens were divided into three groups according to the repair method: Group I- CoJet™ Repair System (3M ESPE) [chairside silica coating with 30 µm SiO2 + silanization + adhesive]; Group II- Ceramic Repair System (Ivoclar Vivadent) [etching with 37% phosphoric acid + Zirconia primer + adhesive]; Group III- Signum Zirconia Bond (Heraus) [Signum Zirconia Bond I + Signum Zirconia Bond II]. Composite resin was polymerized on each conditioned specimen. The shear bond strength was tested using a universal testing machine, and fracture sites were examined with FE-SEM. Surface morphology and wettability after surface treatments were examined additionally. The data of bond strengths were statistically analyzed with one-way ANOVA and Tamhane post hoc test (α=.05).RESULTSIncreased surface roughness and the highest wettability value were observed in the CoJet sand treated specimens. The specimens treated with 37% phosphoric acid and Signum Zirconia Bond I did not show any improvement of surface irregularity, and the lowest wettability value were found in 37% phosphoric acid treated specimens. There was no significant difference in the bond strengths between Group I (7.80 ± 0.76 MPa) and III (8.98 ± 1.39 MPa). Group II (3.21 ± 0.78 MPa) showed a significant difference from other groups (P<.05).CONCLUSIONThe use of Intraoral silica coating system and the application of Signum Zirconia Bond are effective for increasing the bond strength of composite resin to zirconia.

Effect of resin cement selection on the microtensile bond strength of adhesively veneered 3Y-TZP

Objective. The aim of this study was to investigate the effect of resin cement selection on the microtensile bond strength (μTBS) of adhesively veneered 3Y-TZP. Materials and methods. 3Y-TZP discs were fabricated from commercial powders and treated by sandblasting and zirconia primer. Porcelain discs were sectioned from a feldspathic block and conditioned with 5% HF and silane agent. Pre-treated surfaces of zirconia and porcelain discs were bonded together using one of the three following resin cements: Multilink N (MN), Panavia F (PA) or RelyX Unicem (RU), respectively. After light-curing the joined discs were cut into microbars where 15 microbars per group were randomly chosen for μTBS test until failure occurred (24 h storage in water in advance, crosshead speed of 0.5 mm/min). The data were analysed by one-way ANOVA and Tukey's test (p < 0.05). Fractured zirconia surfaces were examined using both a stereomicroscope and scanning electron microscope to identify the failure mode. Results. Significant differences in the μTBS values among three groups were found (p < 0.001) and the descending order was PA, RU and MN. No zirconia or feldspathic failure occurred, but the zirconia/cement interfaces suffered from fracture for all samples. Cement cohesive failure and/or feldspathic/cement interfacial failure sometimes were involved. Failures were mainly adhesive for RU, while they were mixed for MN and PA. Conclusion. When using the adhesive veneering method, Panavia F offers better bond strength than Multilink N or RelyX Unicem, which is probably due to the content of the 10-methacryloyloxydecyl dihydrogenphosphate (10-MDP) monomer.

Improving bonding of zirconia through deposition of silica layer via collosol-gelatin process, the roles of NaHCO3

To evaluate the effects of NaHCO3 on gelation of silica sols and shear bond strength of silica coated zirconia via collosol-gelatin (Sol-Gel) process. The gelation time of silica sols after being mixed with 1%, 3%, 5%, 7%, 10% concentrations of NaHCO3 was recorded. The one got the shortest gelation time was used for the following tests. Zirconia blocks were prepared and divided into five experimental groups according to surface conditioning methods: group A, alumina sandblasting; group B, sandblasting + tribochemical silica coating + silane; group C, sandblasting + silica coating via Sol-Gel process + silane; group D, sandblasting + silica coating via Sol-Gel process (NaHCO3 was used) + silane; group E, sandblasting + zirconia primer. A composite resin column was bonded on the treated zirconia surface with Bis-GMA based composite resin cement. All specimens were subjected to shear bond strength (SBS) tests. The shortest gelation time of silica sols were found when silica sols was mixed with 10% NaHCO3. Group A showed the lowest SBS values of (4.12 ± 0.52) MPa, which was significant different from SBS of group B [(10.24 ± 2.78) MPa], C [(7.36 ± 1.59) MPa], D [(9.79 ± 2.07) MPa], D [(8.39 ± 0.49) MPa], and no statistical difference was found between group C and D. The silica coating via Sol-Gel process can significantly improve the bond strength of zirconia, and NaHCO3 would not exert influences to bonding.

Evaluation of Shear Bond Strength of Zirconia Bonded to Dentin After Various Surface Treatments of Zirconia

Establishing a reliable bond of resin cement to zirconia based materials has been a major limitation against zirconia restoration. This study evaluated the shear bond strength of zirconia bonded to dentin specimens using a self etch dual cure resin cement after various surface treatments of zirconia. Twenty zirconia rods (3×2.5 mm) were prepared from zirconia blocks and assigned into 5 groups for the following surface treatments. (1) Group I: Control (C) no treatment (2) Group II: airborne-particle abrasion (APA), (3) Group III: hydrofluoric acid etching (HF), (4) Group IV: hydrofluoric acid etching followed by silanation (HF/S), and (5) Group V: application of zirconia primer (Z). Dentin Specimens were prepared from extracted molars stored in 0.5% chloramine-T. Zirconia rods were bonded to dentin using resin cement (Multilink Speed), then light polymerized. The specimens tested for failure were tested using the notched shear bond test method in a universal loading apparatus. One way ANOVA followed by Tukey HSD for cell means were used to analyze the data (=0.05). The highest values were obtained with group V (Z) (8.66MPa) followed by group II (APA) (6.71MPa), and group IV (HF/S) (4.41MPa). The least values were obtained for group III (HF) (3.88MPa) with no significant difference (P value 0.53) between group III (HF) (3.88MPa) and group I (C) (3.70MPa). Among the surface treatments employed in this study zirconia primer application is a practical procedure to improved bond strength of zirconia to resin cement followed by Airborne Particle Abrasion with 50μm Al2O3 particles.

Impact of acidic monomer type and concentration on the adhesive performance of dental zirconia primers

This study evaluated the influence of acidic monomer type (phosphate–PAM or carboxylic–CAM) and concentration on the adhesive performance of single-solution model dental zirconia primers to yttria-stabilized polycrystalline dental zirconia ceramic. The acidic monomers 1,3-glycerol dimethacrylate phosphate (PAM) or mono-2-(methacryloyloxy)ethyl maleate (CAM) were added to a photocurable (di)methacrylate co-monomer at mass fractions of 10%, 20%, 40% or 60%, with constant 40% mass of ethanol. The degree of CC conversion (DC) of the primers was measured using mid-infrared spectroscopy. Zirconia bonds were assessed by shear bond strength test after two aging conditions: water storage for 24h or thermal cycling (3,000 cycles in water at 5°C and 55°C). DC data were submitted to one-way ANOVA for each monomer type. Bond strength data were submitted to two-way ANOVA for each aging condition. Bond strengths at 24h and after thermal cycling were compared using t-tests (α=0.05 for all analyses). Lower DC was observed for increased acidic monomer concentrations. The bond strengths of PAM-based primers were generally higher than CAM-based materials, irrespective of acidic monomer concentration or aging condition. After thermal cycling, the bond strengths for PAM-based primers were still higher compared with CAM-based primers, although CAM-based materials generally had more stable zirconia bonds. In conclusion, both the acidic monomer type and concentration had a significant impact on the adhesive performance of the primers. The primer with 40% of phosphate methacrylate showed the best overall bonding performance to dental zirconia.

Surface fluorination of zirconia: Adhesive bond strength comparison to commercial primers

ObjectiveThis study evaluated contact angle and shear bond strength of three commercial zirconia primers and compared them to a recently developed fluorination pre-treatment. Earlier investigations reported that plasma fluorinated zirconia modifies the chemical bonding structure creating a more reactive surface. Materials and methodsYttria-stabilized zirconia (LAVA, 3M ESPE) plates were highly polished using 3μm diamond paste (Ra ∼200nm) prior to pretreatments. After primer and fluorination treatment, contact angles were measured to quantify surface hydrophobicity before and after ethanol clean. Additionally, simple shear bond tests were performed to measure the adhesion strength to a composite resin. ResultsPlasma fluorination produced the lowest contact angle (7.8°) and the highest shear bond strength (37.3MPa) suggesting this pretreatment facilitates a more “chemically” active surface for adhesive bonding. ConclusionsIt is hypothesized that plasma fluorination increase hydroxylation at the surface, making it more reactive, thus allowing for covalent bonding between zirconia surface and resin cement. A strong correlation was observed between contact angle and adhesion strength for all specimens; a relationship which may help understand the frequency and modes of failures, clinically. It is also believed that this surface treatment can increase long-term viability of zirconia restorations over other adhesive techniques.

Bonding of Resin Materials to All-Ceramics: A Review

Problem statement: All-ceramic materials, especially silica-based lithium disilicate and non-silicate-based Zirconia, have become a topic of interest in the field of dentistry. It is still difficult to achieve a strong and durable resin-ceramic adhesion, especially resin-Zirconia bonding. Approach: The article reviews the current literature published in the past 5 years, focusing on the latest resin bonding techniques (including surface treatment, priming and cementation) for dental all-ceramic materials, especially Zirconia and lithium disilicate ceramics. A search of dental literature from PubMed and MEDLINE databases was conducted and the key words included Zirconia, lithium disilicate and bond. Titles and abstracts of the articles listed from search results were reviewed and evaluated for appropriateness. Results: The literature demonstrates that a variety of surface roughness, priming and cementation methods are available for improving resin-ceramic bonding. Conclusion: Available data suggest that the preferred bonding methods for silica-based ceramics are hydrofluoric acid-etching and subsequent silent treatments. The preferred protocol for Zirconia-resin bonding is the combination of surface roughness such as air-abrasion and treatment with a phosphate-containing Zirconia primer followed by cementation with a non-phosphate-containing resin cement.

Acidic monomer type/concentration and the adhesive performance of zirconia primers

Acidic monomer type/concentration and the adhesive performance of zirconia primers

Fatigue resistance and failure mode of adhesively restored custom implant zirconia abutments

This study assessed the fatigue resistance and failure mode of porcelain and composite resin crowns and onlays bonded to premolar custom zirconia implant abutments. Sixty standardized zirconia implant abutments were milled (NeoShape) according to two different restoration designs (onlay or crown). Using Cerec 3, the corresponding onlays and crowns were fabricated either in ceramic (Paradigm C) or composite resin (Paradigm MZ100), resulting in four experimental groups (n = 15). The fitting surfaces of the abutments were airborne-particle abraded and cleaned. The intaglio surfaces of the restorations were HF-etched and silanated (Paradigm C) or airborne-particle abraded and silanated (Paradigm MZ100). Following insertion of the abutments into a Morse taper implant (Titamax CM), all restorations were bonded with a zirconia primer (Z-Prime Plus), adhesive resin (Optibond FL), and a preheated light curing composite resin (Filtek Z100). Cyclic isometric chewing (5 Hz) was simulated, starting with a load of 50N (5000×), followed by stages of 200N, 400N, 600N, 800N, 1000N, 1200N, and 1400N (25,000× each). Samples were loaded until fracture or to a maximum of 180,000 cycles. The four groups were compared using the life table survival analysis (Logrank test at P = 0.05). All composite resin onlays and crowns survived (100% survival rate), while ceramic ones fractured at an average load of 1347N and 1280N, respectively, (survival rate of 46.7% and 20%) with a significant difference in survival probability (P < 0.0001). Fractures consisted in partial or total failure of the restoration only (no abutment failure, no screw loosening). Composite resin onlays and crowns bonded to custom zirconia implant abutments presented a significant higher survival rate when compared to ceramic onlays and crowns.

Combined Novel Bonding Method of Resin to Zirconia Ceramic in Dentistry: A Pilot Study

Zirconia is a promising metal-free framework material that can be used to construct all-ceramic resin-bonded restorations in modern minimally invasive dentistry. The lack of a durable bond to zirconia is the major limitation against its widespread use. A technique to promote adhesion to the zirconia surface has thus been actively sought in dental materials research. Selective infiltration etching (SIE) has emerged as a method of conditioning that creates a highly retentive zirconia surface. This in vitro pilot study tested a novel adhesion procedure in which two newly engineered silane-based zirconia primers were combined with the SIE method. Zirconia discs were SIE-surface-treated, coated with one of the 2 zirconia primers, and bonded to composite resin discs. Primer activation (hydrolysis) was monitored by Fourier transform infrared (FTIR) spectroscopy. The bilayered specimens were sectioned into microbars and subjected to the microtensile bond strength test. As-sintered zirconia discs served as controls. Surface analysis of zirconia specimens was carried out using photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Zirconia specimens that had been treated with both SIE and primers had a significantly higher (ANOVA) zirconia resin bond strength (40.6 MPa, SD 5.8 MPa) than control specimens (2.6 MPa, SD 3.0 MPa; p < 0.05, F = 13.8, ANOVA). Controls also exhibited spontaneous failure during sectioning. Additionally, the interfacial failure rate was lower for the specimens subjected to the new combined surface treatment than for controls. The novel combined method of surface treatment method might open new opportunities for enhanced adhesion of resin-bonded zirconia restorations.

Fatigue resistance and failure mode of novel-design anterior single-tooth implant restorations: influence of material selection for type III veneers bonded to zirconia abutments

This study assessed the fatigue resistance and failure mode of type III porcelain and composite resin veneers bonded to custom zirconia implant abutments. Twenty-four standardized zirconia implant abutments were fabricated. Using the CEREC 3 machine, type III veneers of standardized shape were milled in ceramic Vita Mark II or in composite resin Paradigm MZ100. The intaglio surfaces of the restorations were hydrofluoric acid etched and silanated (Mark II) or airborne-particle abraded and silanated (MZ100). The fitting surface of the abutments was airborne-particle abraded, cleaned, and inserted into a bone level implant (BLI RC SLActive 10 mm). All veneers (n=24) were adhesively luted with a zirconia primer (Z-Prime Plus), adhesive resin (Optibond FL) and a pre-heated light-curing composite resin (Filtek Z100). Cyclic isometric chewing (5 Hz) was simulated, starting with a load of 40 N, followed by stages of 80, 120, 160, 200, 240, and 280 N (20,000 cycles each). Samples were loaded until fracture or to a maximum of 140,000 cycles. Groups were compared using the life table survival analysis (Logrank test at P=.05). Mark II and MZ100 specimens fractured at an average load of 216 N and 229 N (survival rate of 17% and 8%), respectively, with no difference in survival probability (P=.18). Among the fractured samples, 40% of the failures were at the abutment level for Mark II and 27% were at the abutment level for MZ100. No exclusive adhesive failures were observed. Type III Mark II and Paradigm MZ100 veneers showed similar fatigue resistance when bonded to custom non-retentive zirconia implant abutments. The bond was strong enough to induce abutment fractures. MZ100 presented a higher percentage of "friendly" failures, i.e. maintaining the restoration-abutment adhesive interface and the abutment itself intact.

The effect of zirconia surface treatment on flexural strength and shear bond strength to a resin cement

Despite the expanded applications for zirconia in restorative dentistry, there is no clear recommendation in the literature regarding surface treatment before bonding. The purpose of this study was to evaluate the effect of mechanical surface treatment of yttria-partially stabilized zirconia on its flexural strength and the effect of mechanical and chemical surface treatments on its bond strength to a resin cement. For flexural strength evaluation, zirconia bars (4 x 5 x 40 mm) were prepared from zirconia blocks, finished using a diamond rotary cutting instrument, sintered, then assigned into 4 groups: (1) control (no treatment), (2) airborne-particle abrasion, (3) silicoating, and (4) wet hand grinding. After storage for 24 hours at 37 degrees C, flexural strength was determined using a 3-point bending test, and the results were analyzed using 1-way ANOVA (alpha=.05). For shear bond strength evaluation, zirconia rods (2.5 x 3 mm) were prepared from zirconia blocks, sintered, and assigned into 16 groups. Each group underwent a combination of the following mechanical and chemical treatments. Mechanical treatment included: (1) control (no treatment), (2) airborne-particle abrasion, (3) silicoating, or (4) wet hand grinding. Chemical treatment included: (1) control (no treatment), (2) acid etching followed by silanation, (3) silanation only, or (4) application of zirconia primer. Dentin specimens were prepared from extracted molars stored in 0.5% chloramine-T. Zirconia rods were bonded to dentin using a resin cement (Multilink Automix), then light polymerized. After storage, the specimens were loaded to failure with the notched shear bond test method in a universal loading apparatus. For artificial aging analysis, the groups that achieved the highest bond strength values were duplicated, stored at 37 degrees C and 100% humidity for 90 days, and thermal cycled before being loaded to failure. Results were analyzed using 2-way ANOVA (alpha=.05). Airborne-particle abrasion and hand grinding significantly increased flexural strength. The highest shear bond strength values were achieved for the following groups: silicoated + silanated > hand ground + zirconia primer > airborne-particle abraded + silanated > zirconia primer > airborne-particle abraded + zirconia primer. Artificial aging resulted in significantly lower shear bond strength for the silicoated/silanated and the zirconia primer groups. Mechanical modification of the surface increased the flexural strength of Y-TZP. The resin bond to Y-TZP was improved by surface treatment. A combination of mechanical and chemical conditioning of the zirconia surface was essential to develop a durable resin bond to zirconia.

New zirconia primer improves bond strength of resin-based cements

Objective Various chemical interactions can be used to develop ceramic–resin bonding and specific approaches are available for zirconia ceramics. This study evaluated the effect of a new experimental primer, a mixture of organophosphate and carboxylic acid monomers, on the zirconia-to-resin shear bond strength (SBS). Methods Forty Y-TZP blocks (15 × 4 × 2 mm) were embedded in an acrylic resin base, polished, Al 2O 3-sandblasted and randomly divided into eight groups. Three different resin-based luting agents (BisCem, Duo-Link, Panavia F) were used to build 2.4 mm-diameter cylinders ( n = 15) onto the zirconia surface with and without the new experimental zirconia primer. The new primer was also tested with Z100 restorative composite resin cylinders. In addition, Panavia was used with its own primer (Clearfil Ceramic Primer). SBS testing was carried out after 24 h of storage in water. Scanning electron microscopy (SEM) was used to evaluate the zirconia surface topography and failure mode. Results According to ANOVA and Tukey test ( α = 0.05), the association of the experimental primer with the restorative composite resin Z100 yielded the highest SBS (29.35 MPa) followed by DuoLink with the new primer (26.68 MPa). The groups that did not receive the experimental primer presented the lowest SBS values (from 5.95 to 9.79 MPa). The failure mode was adhesive for the non-primed specimens and predominantly mixed in the primed groups. Significance The use of the new zirconia experimental primer based on organophosphate/carboxylic acid monomers increased the bond strength of different resin-based luting agents including Z100 restorative material.

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.