In vitro evaluation of long-term bonding of Procera AllCeram alumina restorations with a modified resin luting agent

STATEMENT OF PROBLEM: Bonded densely sintered aluminum oxide ceramic restorations such as Procera AllCeram laminates rely on a strong and long-term durable resin bond. Air particle abrasion and a phosphate-modified resin luting agent have the potential to provide such bonds to aluminum oxide ceramics, but their efficacy on the Procera AllCeram intaglio surface is unknown. The inherent microroughness of this surface may influence bond strengths, because micromechanical interlocking is a main contributor for adhesion of resins to ceramic materials. PURPOSE: This study evaluated the bond strength of a phosphate-modified resin luting agent with and without silanization to an air particle-abraded Procera AllCeram intaglio surface compared with a conventional resin-bonding system before and after artificial aging. MATERIAL AND METHODS: Sixty square (10 x 10 x 2 mm) specimens of Procera AllCeram alumina ceramic with the Procera intaglio surface were air particle abraded with aluminum oxide. Composite cylinders (2.9 mm in diameter and 3.0 mm in width) were fabricated with Z-250 composite and bonded to the ceramic specimens with either Panavia 21 TC or Rely X ARC (control) and their corresponding bonding/silane coupling agents. In addition, Panavia was used without silanization as suggested in similar studies. Subgroups of 10 specimens were stored in distilled water for either 3 or 180 days before shear bond strength was tested with a universal testing machine (MPa) until fracture. The 180-day specimens were subjected to thermocycling at 2000 cycles every 30 days (12,000 cycles total). Data were analyzed with 1-way analysis of variance and Tukey's multiple comparison (alpha=.05). Failure modes were examined with a light microscope (original magnification x 25). RESULTS: Differences between short-term and long-term groups were highly significant (P=.000). Bond strength with Rely X ARC and its silane coupling agent (22.75 +/- 4 MPa) decreased significantly (P=.000) after artificial aging (3.32 +/- 3.62 MPa). Panavia 21 after silanization revealed significantly different (P=.003) early (21.42 +/- 4.3 MPa) and late (16.09 +/- 2.37 MPa) bond strengths but achieved the highest bond strength after artificial aging. Bond strengths of Panavia without silanization both early (8.06 +/- 2.1 MPa) and late (6.91 +/- 2.49 MPa) were not significantly different. Failure modes were mainly adhesive at the ceramic surface for all groups. CONCLUSION: Panavia 21 in combination with its corresponding bonding/silane coupling agent can achieve an acceptable resin bond to the air particle-abraded intaglio surface of Procera AllCeram restorations after artificial aging, which had mixed effects on the other investigated groups. The conventional resin luting agent revealed the most dramatic decrease in bond strength.     

Durability of the resin bond strength to the alumina ceramic Procera.

OBJECTIVES: The purpose of this in vitro study was to evaluate the tensile bond strength of adhesive bonding systems to the densely sintered alumina ceramic Procera, and its durability. METHODS: Plexiglas tubes filled with composite resin were bonded to Procera ceramic discs (99% Al2O3), which were either in their original state as supplied by the manufacturer or which were sandblasted for surface conditioning. Groups of 20 specimens were bonded in an alignment apparatus using 10 bonding methods. Subgroups of 10 bonded specimens were tested for tensile strength following storage in distilled water at 37 degrees C either for 3 days or for 150 days. In addition, the 150 days specimens were thermal cycled 37,500 times. The statistical analyses were conducted with the Kruskal-Wallis test followed by multiple pair-wise comparison of groups using the Wilcoxon rank sum test. RESULTS: Not sandblasted groups showed relatively poor initial bond strengths independent from bonding resins. During 150 days storage time all specimens in the not sandblasted groups debonded spontaneously. Moderate to relatively high initial bond strengths between 18 and 39 MPa were achieved to sandblasted specimens by using the PMMA luting resin Superbond C & B or the composite resin Variolink II or by silica coating and silanation in combination with Variolink II. However, in these groups after 150 days storage time the bond strength decreased significantly. The phosphate monomer containing composite resin Panavia 21 showed the highest bond strength to sandblasted Procera ceramic which did not decrease significantly over storage time. In addition, the bond strengths of sandblasted groups bonded with Variolink II after priming the ceramic with Alloy Primer or the silane Monobond S were relatively high and did also not decrease significantly after 150 days storage time. SIGNIFICANCE: Using ten bonding systems, a stable resin bond to Procera ceramic could be achieved after sandblasting and by using Panavia 21 or by using Variolink II after priming the ceramic with Alloy Primer or Monobond S.     

The effect of ceramic surface treatment on bonding to densely sintered alumina ceramic

STATEMENT OF PROBLEM: Ceramic surface treatment is crucial for bonding to resin. High crystalline ceramics are poorly conditioned using traditional procedures. PURPOSE: The purpose of this study was to evaluate the effect of silica coating on a densely sintered alumina ceramic relative to its bond strength to composite, using a resin luting agent. Material and methods Blocks (6 x 6 x 5 mm) of ceramic and composite were made. The ceramic (Procera AllCeram) surfaces were polished, and the blocks were divided into 3 groups (n = 5): SB, airborne-particle abrasion with 110-microm Al 2 O 3 ; RS, silica coating using Rocatec System; and CS, silica coating using CoJet System. The treated ceramic blocks were luted to the composite (W3D Master) blocks using a resin luting agent (Panavia F). Specimens were stored in distilled water at 37 degrees C for 7 days and then cut in 2 axes, x and y, to obtain specimens with a bonding area of approximately 0.6 mm 2 (n = 30). The specimens were loaded to failure in tension in a universal testing machine, and data were statistically analyzed using a randomized complete block design analysis of variance and Tukey's test (alpha=.05). Fractured surfaces were examined using light microscopy and scanning electron microscopy to determine the type of failure. Energy-dispersive spectroscopy was used for surface compositional analysis. RESULTS: Mean bond strength values (MPa) of Groups RS (17.1 +/- 3.9) ( P =.00015) and CS (18.5 +/- 4.7) ( P =.00012) were significantly higher than the values of Group SB (12.7 +/- 2.6). There was no statistical difference between Groups RS and CS. All failures occurred at the adhesive zone. CONCLUSION: Tribochemical silica coating systems increased the tensile bond strength values between Panavia F and Procera AllCeram ceramic.     

In vitro evaluation of shear bond strengths of resin to densely-sintered high-purity zirconium-oxide ceramic after long-term storage and thermal cycling

STATEMENT OF PROBLEM: The few available studies on the resin bond to zirconium-oxide ceramic recommend airborne-particle abrasion and modified resin luting agents containing adhesive monomers for superior and long-term durable bond strengths. It is unknown whether this regimen can also be successfully applied to the intaglio surface of a commercial zirconia-based all-ceramic system. PURPOSE: The purpose of this study was to evaluate and compare bond strengths of different bonding/silane coupling agents and resin luting agents to zirconia ceramic before and after artificial aging. MATERIAL AND METHODS: Composite cylinders (2.9 mm x 3.0 mm) were bonded to airborne-particle-abraded intaglio surfaces of Procera AllZirkon specimens (n=80) with either Panavia F (PAN) or Rely X ARC (REL) resin luting agents after pretreatment with Clearfil SE Bond/ Porcelain Bond Activator (Group SE). In another group, Rely X ARC was used with its bonding/silane coupling agent (Single Bond/Ceramic Primer, Group SB). PAN without any bonding/silane agent (Group NO) was the control. Subgroups of 10 specimens were stored in distilled water for either 3 or 180 days before shear bond strength was tested. One hundred eighty-day-old specimens were repeatedly thermal cycled for 12,000 cycles between 5 and 60 degrees C with a 15-second dwell time. Data were analyzed with 1- and 2-way analysis of variance and the Tukey multiple comparisons test (alpha=.05). Failure modes were examined under original magnification x25. RESULTS: After 3 days, SE-REL (25.15 +/- 3.48 MPa) and SE-PAN (20.14 +/- 2.59 MPa) groups had significantly superior mean shear bond strengths (P=.0007) compared with either NO-PAN (17.36 +/- 3.05 MPa) or SB-REL (16.90 +/- 7.22 MPa). SE-PAN, NO-PAN, and SB-REL groups were not significantly different. Artificial aging significantly reduced bond strengths. After 180-day storage, SE-PAN (16.85 +/- 3.72 MPa), and SE-REL (15.45 +/- 3.79 MPa) groups demonstrated significantly higher shear bond strengths than NO-PAN (9.45 +/- 5.06 MPa) or SB-REL (1.08 +/- 1.85 MPa) groups. The modes of failure varied among 3-day groups but were 100% adhesive at the ceramic surfaces after artificial aging. CONCLUSION: Artificial aging significantly reduced bond strength. A bonding/silane coupling agent containing an adhesive phosphate monomer can achieve superior long-term shear bond strength to airborne-particle- abraded Procera AllZirkon restorations with either one of the 2 resin luting agents tested.     

Effect of zirconium-oxide ceramic surface treatments on the bond strength to adhesive resin

STATEMENT OF PROBLEM: Surface treatment methods used for resin bonding to conventional silica-based dental ceramics are not reliable for zirconium-oxide ceramics. PURPOSE: The aim of this study was to compare the effects of airborne-particle abrasion, silanization, tribochemical silica coating, and a combination of bonding/silane coupling agent surface treatment methods on the bond strength of zirconium-oxide ceramic to a resin luting agent. MATERIAL AND METHODS: Sixty square-shaped (5 x 5 x 1.5 mm) zirconium-oxide ceramic (Cercon) specimens and composite resin (Z-250) cylinders (3 x 3 mm) were prepared. The ceramic surfaces were airborne-particle abraded with 125-microm aluminum-oxide (Al(2)O(3)) particles and then divided into 6 groups (n = 10) that were subsequently treated as follows: Group C, no treatment (control); Group SIL, silanized with a silane coupling agent (Clearfil Porcelain Bond Activator); Group BSIL, application of the adhesive 10-methacryloyloxydecyl dihydrogen phosphate monomer (MDP)-containing bonding/silane coupling agent mixture (Clearfil Liner Bond 2V/ Porcelain Bond Activator); Group SC, silica coating using 30-microm Al(2)O(3) particles modified by silica (CoJet System); Group SCSIL, silica coating and silanization (CoJet System); and Group SCBSIL, silica coating and application of an MDP-containing bonding/silane coupling agent mixture (Clearfil Liner Bond 2V/Porcelain Bond Activator). The composite resin cylinders were bonded to the treated ceramic surfaces using an adhesive phosphate monomer-containing resin luting agent (Panavia F). After the specimens were stored in distilled water at 37 degrees C for 24 hours, their shear bonding strength was tested using a universal testing machine at a crosshead speed of 0.5 mm/min. Debonded specimen surfaces were examined with a stereomicroscope to assess the mode of failure, and the treated surfaces were observed by scanning electron microscopy. Bond strength data were analyzed using 1-way analysis of variance and the Duncan test (alpha = .05). RESULTS: The bond strengths (mean +/- SD; MPa) in the groups were as follows: Group C, 15.7 +/- 2.9; Group SIL, 16.5 +/- 3.4; Group BSIL, 18.8 +/- 2.8; Group SC, 21.6 +/- 3.6; Group SCSIL, 21.9 +/- 3.9; and Group SCBSIL, 22.9 +/- 3.1. The bond strength was significantly higher in Group SCBSIL than in Groups C, SIL, and BSIL (P<.001), but did not differ significantly from those in Groups SC and SCSIL. Failure modes were primarily adhesive at the interface between zirconium and the resin luting agent in Groups C and SIL, and primarily mixed and cohesive in Groups SC, SCSIL, and SCBSIL. CONCLUSION: Tribochemical silica coating (CoJet System) and the application of an MDP-containing bonding/silane coupling agent mixture increased the shear bond strength between zirconium-oxide ceramic and resin luting agent (Panavia F).     

摩擦化学法硅涂层对氧化锆陶瓷粘接强度的影响

目的： 评估摩擦化学法硅涂层对氧化锆陶瓷粘接强度的影响。方法： 将切割烧结后的Lava氧化锆瓷块60件分为6组，每2组分别经喷砂/硅烷偶联剂、喷砂/CoJet Sand/硅烷偶联剂、无处理3种表面处理后，相同表面处理的2组中，每组分别用RelyX Unicem或Panavia F2.0与牙釉质粘接。各组随机抽取5件共30件进行24 h水浴，其余30件进行5000周水热循环，然后进行剪切粘接强度测试。采用SPSS 23.0软件包对数据进行双因素方差分析、Tukey HSD多重比较法及t检验。结果： 喷砂/CoJet/硅烷组的剪切强度均显著高于其他2组（P<0.001）；经老化试验后，喷砂/CoJet/硅烷组使用RelyX Unicem仍保持较高的剪切强度[(21.374±4.433)MPa]，与其他各组相比有显著差异（P<0.001）。结论： 摩擦化学法硅涂层能够有效提高氧化锆的粘接强度及耐久性，表面处理方式与粘接剂之间的相互作用需得到临床关注。     

Shear bond strength of a new resin bonding system to different ceramic restorations

This study evaluated the shear bond strength of a newly developed resin bonding system, including single-liquid ceramic primer and dual-cured resin luting agent, to 5 ceramic materials (feldspathic porcelain, machinable ceramic, In-Ceram Alumina, Procera AllCeram alumina, and Cercon). Ceramic specimens were cleaned with phosphoric acid, treated with primer, and bonded with a resin luting agent. Shear bond strength was determined after 24 hours of immersion in water and/or 10,000 thermocycles. There were no significant differences in bond strength before and after thermocycling for the 5 ceramic materials (P > .05). The findings indicate that the resin bonding system may offer an acceptable performance in terms of clinical success for the 5 ceramic restorations.     

Bonding to densely sintered alumina- and glass infiltrated aluminum / zirconium-based ceramics

The objective of this study was to test two hypotheses: (1) silica coating affects the bond strength between ceramics and a resin cement; (2) bond strength is affected by the type of ceramic. Twelve blocks 5 x 6 x 8 mm of In-Ceram Zirconia (ZR) and twelve Procera AllCeram (PR) ceramics were made and duplicated in composite. Five blocks of each ceramic were treated as follows: (1) ZR + GB (laboratorial airborne particles abrasion with Al2O3 particles) + silane; (2) ZR + SC (chairside tribochemical silica coating system, Cojet); (3) PR + GB; (4) PR + SC. Two treated samples of ceramic were analyzed under SEM. The ceramic-composite blocks were cemented with Panavia F and stored in 37oC distilled water for 7 days. They were then cut to produce bar specimens (n=30) with a bonding area of 0.6±0.1mm2. Specimens were loaded to failure under tension in a universal testing machine (1 mm/min). Bond strength (sigma) values were statistically analyzed using ANOVA (Two-way) and Tukey (alpha = 0.05). Mean sigma (MPa) and standard deviation were as follows: 1) 15.1 ± 5.3; 2) 26.8 ± 7.4; 3) 12.7 ± 2.6; 4) 18.5 ± 4.7. Silica coated surfaces showed statistically higher sigma than the same substrate treated with GB only. In addition, ZR (with vitreous phase) showed higher ó than PR (without vitreous phase).     

Bond strength of a resin cement to high-alumina and zirconia-reinforced ceramics: the effect of surface conditioning

PURPOSE: The aim of this study was to evaluate the effect of two surface conditioning methods on the microtensile bond strength of a resin cement to three high-strength core ceramics: high alumina-based (In-Ceram Alumina, Procera AllCeram) and zirconia-reinforced alumina-based (In-Ceram Zirconia) ceramics. MATERIALS AND METHODS: Ten blocks (5 x 6 x 8 mm) of In-Ceram Alumina (AL), In-Ceram Zirconia (ZR), and Procera (PR) ceramics were fabricated according to each manufacturer's instructions and duplicated in composite. The specimens were assigned to one of the two following treatment conditions: (1) airborne particle abrasion with 110-microm Al2O3 particles + silanization, (2) silica coating with 30 microm SiOx particles (CoJet, 3M ESPE) + silanization. Each ceramic block was duplicated in composite resin (W3D-Master, Wilcos, Petrópolis, RJ, Brazil) using a mold made out of silicon impression material. Composite resin layers were incrementally condensed into the mold to fill up the mold and each layer was light polymerized for 40 s. The composite blocks were bonded to the surface-conditioned ceramic blocks using a resin cement system (Panavia F, Kuraray, Okayama, Japan). One composite resin block was fabricated for each ceramic block. The ceramic-composite was stored at 37 degrees C in distilled water for 7 days prior to bond tests. The blocks were cut under water cooling to produce bar specimens (n = 30) with a bonding area of approximately 0.6 mm2. The bond strength tests were performed in a universal testing machine (crosshead speed: 1 mm/min). Bond strength values were statistically analyzed using two-way ANOVA and Tukey's test (< or = 0.05). RESULTS: Silica coating with silanization increased the bond strength significantly for all three high-strength ceramics (18.5 to 31.2 MPa) compared to that of airborne particle abrasion with 110-microm Al2O3 (12.7-17.3 MPa) (ANOVA, p < 0.05). PR exhibited the lowest bond strengths after both Al2O3 and silica coating (12.7 and 18.5 MPa, respectively). CONCLUSION: Conditioning the high-strength ceramic surfaces with silica coating and silanization provided higher bond strengths of the resin cement than with airborne particle abrasion with 110-microm Al2O3 and silanization.     

The effect of surface preparation and luting agent on bond strength to a zirconium-based ceramic

OBJECTIVES: To investigate the bond strength of modern "self-adhesive" resin cements to a zirconium-based dental ceramic following different surface preparations and storage conditions. METHODS: The surface of zirconium-based ceramic discs (12 x 2 mm) were either left untreated, prepared using alumina grit-blasting or tribochemical treatment. Resin composite cylinders were bonded to ceramic specimens using Panavia-F, RelyX Unicem or Maxcem resin cements. The shear bond strength of specimens (n = 10) was tested "dry," following 24-hour water immersion or a thermocycling regime. RESULTS: For each surface preparation, a significant reduction in bond strength following 24-hour water immersion and thermocycling compared to "dry" storage conditions was identified for both Panavia-F and Maxcem. However, Unicem specimens exhibited statistically similar SBS values for tribochemically-treated specimens stored dry following 24-hour water immersion or thermocycling (11.7 +/- 1.3, 14.1 +/- 6.3 and 11.7 +/- 4.9 MPa, respectively) (p > 0.05). No significant differences in bond strength were identified for Panavia-F or Unicem specimens for any surface preparation following the thermocycling regime (p > 0.05). In contrast, for each surface preparation following thermocycling (p < 0.001), Maxcem exhibited a significant decrease in SBS compared with Panavia-F and Unicem specimens. CONCLUSIONS: The pre-treatment of a zirconium-based ceramic surface with grit-blasting and tribochemical treatment improves the bond strength of resin cements. Following "wet" storage conditions, Panavia-F and Unicem demonstrated superior bond strength compared with Maxcem. Differences in ceramic surface preparation and the chemistry of resin cements will affect the nature of the bonding mechanism and durability of the adhesive layer.     

Effect of thermocycling on bond strength of luting cements to zirconia ceramic.

OBJECTIVES: The aim of this study was to evaluate the shear bond strength of different cements to densely sintered zirconia ceramic after aging by thermocycling. METHODS: The following luting cements for bonding ZrO2-TZP (tetragonal zirconia polycrystals) were used in this study: Ketac-Cem, Nexus, Rely X Unicem, Superbond C&B, Panavia F, and Panavia 21. Groups of 30 test specimens were prepared by bonding stainless steel cylinders tribochemically silica-coated with the Rocatec-system to sandblasted ZrO2-TZP ceramic disks (cercon smart ceramics). Prior to testing all bonded specimens were stored in distilled water (37 degrees C) for 48 h and half of them (n=15) were additionally aged by thermocycling (10,000 times). RESULTS: None of the fractures occurred at the interface of the metallic rods. The assemblies failed either at the interface between the ceramic surface and the cements or within the cements. Thermocycling affected the bond strength of all luting cements studied except for both Panavia materials and Rely X Unicem. SIGNIFICANCE: Within the limits of this in vitro study the results showed that-after thermocycling-bond strengths for Ketac-Cem and Nexus were quite low. Nexus in combination with tribochemical silica-coating of ceramic surface produced a higher bond strength. The four adhesive resin cements (Rely X Unicem, Superbond C&B, Panavia F, and Panavia 21) gave superior results. The strongest bond to zirconia was obtained with Panavia 21.     

Effects of silica coating and silane surface conditioning on the bond strength of metal and ceramic brackets to enamel

OBJECTIVE: To evaluate the effect of tribochemical silica coating and silane surface conditioning on the bond strength of metal and ceramic brackets bonded to enamel surfaces with light-cured composite resin. MATERIALS AND METHODS: Twenty metal and 20 ceramic brackets were divided into four groups (n = 10 for each group). The specimens were randomly assigned to one of the following treatment conditions of the metal and ceramic brackets' surface: (1) tribochemical silica coating combined with silane and (2) no treatment. Brackets were bonded to the enamel surface on the labial and lingual sides of human maxillary premolars (20 total) with a light-polymerized resin composite. All specimens were stored in water for 1 week at 37 degrees C and then thermocycled (5000 cycles, 5 degrees C to 55 degrees C, 30 seconds). The shear bond strength values were measured on a universal testing machine. Student's t-test was used to compare the data (alpha = 0.05). The types of failures were observed using a stereomicroscope. RESULTS: Metal and ceramic brackets treated with silica coating with silanization had significantly greater bond strength values (metal brackets: 14.2 +/- 1.7 MPa, P < .01; ceramic brackets: 25.9 +/- 4.4 MPa, P < .0001) than the control groups (metal brackets: 11.9 +/- 1.3 MPa; ceramic brackets: 15.6 +/- 4.2 MPa). Treated specimens of metal and ceramic exhibited cohesive failures in resin and adhesive failures at the enamel-adhesive interface, whereas control specimens showed mixed types of failures. CONCLUSIONS: Silica coating with aluminum trioxide particles coated with silica followed by silanization gave higher bond strengths in both metal and ceramic brackets than in the control group.     

Resin microtensile bond strength to feldspathic ceramic: hydrofluoric acid etching vs. tribochemical silica coating

This study aimed to compare the microtensile bond strength of resin cement to alumina-reinforced feldspathic ceramic submitted to acid etching or chairside tribochemical silica coating. Ten blocks of Vitadur-alpha were randomly divided into 2 groups according to conditioning method: (1) etching with 9.6% hydrofluoric acid or (2) chairside tribochemical silica coating. Each ceramic block was luted to the corresponding resin composite block with the resin cement (Panavia F). Next, bar specimens were produced for microtensile testing. No significant difference was observed between the 2 experimental groups (Student ttest, P > .05). Both surface treatments showed similar microtensile bond strength values.     

Long-term resin bond to densely sintered aluminum oxide ceramic

Background: Densely sintered aluminium oxide ceramic is a popular material for ceramic copings and all‐ceramic restorations. A strong, predictable, and long‐term durable resin bond is key for long‐term clinical success of bonded alumina‐based restorations. Purpose: The purpose of this study was to measure and compare in vitro shear bond strengths of three resin cements with and without their corresponding silane coupling/bonding agent to air particle‐abraded densely sintered aluminum oxide ceramic after long‐term water storage and thermocycling. Materials and Methods: Composite resin cylinders were bonded to air particle‐abraded samples of densely sintered aluminum oxide ceramic with Noribond DC® (Noritake Dental Supply, Inc., Aichi, Japan), Panavia 21® EX (Kuraray, Osaka, Japan), and Variolink II® (Ivoclar Vivadent, Schaan, Liechtenstein), which were used with and without their corresponding silane coupling and bonding agents (n= 15). All specimens (N= 90) were stored for 180 days in water and subjected to repeated thermocycling for a total of 12,000 cycles before shear bond strength was tested. Data were analyzed with the Kruskal‐Wallis test and the Wilcoxon two‐sample rank sum test at the 5% level of significance. Results: Most groups had no or only minimal bond strength to densely sintered alumina after simulated aging. Panavia had the highest bond strength without silane/bonding agent application. Noribond with its silane/bonding agent revealed the highest overall bond strength, which was significantly greater than that of either Variolink or Panavia after silanization. Conclusions: Resin cements revealed significantly different bond strengths, and the use of silane coupling and bonding agents had various effects on the resin bond to pure densely sintered alumina. CLINICAL SIGNIFICANCE Selection of the proper cement/bonding system is fundamental to clinical long‐term success of bonded alumina‐based restorations. Noribond with its bonding agent and ceramic primer seem to fulfill these requirements under clinically relevant testing conditions.     

Bonding polycarbonate brackets to ceramic: effects of substrate treatment on bond strength.

This study evaluated the effects of 5 different surface conditioning methods on the bond strength of polycarbonate brackets bonded to ceramic surfaces with resin based cement. Six disc-shaped ceramic specimens (feldspathic porcelain) with glazed surfaces were used for each group. The specimens were randomly assigned to 1 of the following treatment conditions of the ceramic surface: (1) orthophosphoric acid + primer + bonding agent, (2) hydrofluoric acid gel + primer + bonding agent, (3) tribochemical silica coating (silicon dioxide, 30microm) + silane, (4) airborne particle abrasion (aluminum trioxide, 30microm) + silane, and (5) airborne particle abrasion (aluminum trioxide, 30microm) + silane + bonding agent. Brackets were bonded to the conditioned ceramic specimens with a light-polymerized resin composite. All specimens were stored in water for 1 week at 37 degrees C and then thermocycled (1000 cycles, 5 degrees C to 55 degrees C, 30 seconds). The shear bond strength values were measured on a universal testing machine at a crosshead speed of 1 mm/min. Brackets treated with silica coating with silanization had significantly greater bond strength values (13.6 MPa, P =.01) than brackets treated with orthophosphoric acid (8.5 MPa). There was no significant difference (P =.97) between the bond strengths obtained after airborne abrasion with aluminium trioxide particles followed by silanization (12 MPa) and hydrofluoric acid application (11.2 MPa) (ANOVA and Tukey test). Although brackets conditioned with orthophosphoric acid exhibited only adhesive failures of the luting cement from the ceramic surface, other conditioning methods showed mixed types of failures. Airborne particle abrasion with aluminium trioxide or silica coating followed by silanization gave the most favorable bond strengths. The types of failures observed after debonding indicated that the critical parameter was the strength of the adhesive joint of the luting cement to both the bracket and the ceramic.     

Effect of surface treatments on the resin bond to zirconium-based ceramic

PURPOSE: This study tested the hypothesis that the tribochemical silica coating on ceramic surfaces increases the bond strength of resin cement to a glass-infiltrated zirconium-based ceramic. MATERIALS AND METHODS: Fifteen blocks of In-Ceram Zirconia from CEREC InLab (5 per group) and 15 composite blocks (Z-250) 5 mm x 5 mm x 4 mm were made. The ceramic surfaces were polished, and the blocks were divided into three groups: (1) airborne abrasion with 110-microm aluminum oxide particles; (2) Rocatec system, tribochemical silica coating; and (3) CoJet system, tribochemical silica coating. The ceramic blocks were cemented to the composite blocks using Panavia F according to the manufacturer's specifications. All samples were stored in 37 degrees C distilled water for 7 days and later sectioned in two axes using a diamond disk under cooling to obtain specimens with a cross-sectional area of approximately 1 mm2 (n = 45). Each specimen was then attached with cyanoacrylate glue to an adapted device for the microtensile test, which was carried out on a universal testing machine. RESULTS: The results were subjected to ANOVA and Tukey's test. Group 2 (23.0+/-6.7 MPa) and group 3 (26.8+/-7.4 MPa) showed greater bond strength than group 1 (15.1+/-5.3 MPa). There was no significant difference between groups 2 and 3. All failures were in the adhesive zone. CONCLUSION: The hypothesis was confirmed--the tribochemical systems increased the bond strength between Panavia F and In-Ceram Zirconia.     

Study of thermocycling effect on the bond strength between an aluminous ceramic and a resin cement

This study evaluated the effect of thermocycling on the bond strength between Procera AllCeram (Nobel-Biocare) and a resin cement (Panavia F, Kuraray CO). Nine ceramic blocks with dimensions of 5x6x6mm were conditioned at one face with Rocatec System (Espe). After, they were luted with Panavia F to composite resin blocks (Clearfil AP-X, Kuraray CO). The nine groups formed by ceramic, cement and composite resin were split up obtaining 75 samples with dimensions of 12x1x1mm and adhesive surface presenting 1mm2±0.1mm2 of area. The samples were divided into 3 groups (n=25): G1 - 14 days in distilled water at 37oC; G2 - 6,000 cycles in water (5oC - 55oC - 30s); G3 - 12,000 cycles in water (5oC - 55oC - 30s). The samples were tested in a universal testing machine (EMIC) at a crosshead speed of 1mm/min. Data were analyzed by ANOVA and Tukey tests. The results indicated that mean values of rupture tension (MPa) of G1 (10.71 ± 3.54) did not differ statistically (p <5%) from G2 (9.01 ± 3.90), however there was statistical difference between G1 and G3 (7.28 ± 3.00). It was concluded that thermocycling significantly reduced the bond strength values when samples were submitted to 12,000 cycles.     

Influence of silanization on early bond strength to sandblasted densely sintered alumina.

OBJECTIVE: The increased popularity of alumina-based restorations has resulted in an interest in proper adhesive techniques to assure a strong and predictable bond to these restorations. This study investigated the early bond strength of three different resin-cement systems to densely sintered alumina (aluminum-oxide ceramic) with and without the use of their corresponding silane coupling agent (silanization). METHOD AND MATERIALS: Ninety samples of densely sintered high-purity aluminum-oxide ceramic were randomly divided into three groups. Composite cylinders were bonded to the ceramic samples with three resin-cement/bonding-agent systems: Noribond DC (NOR), Panavia 21 EX (PAN), and Variolink II (VAR). Each resin-cement/bonding-agent system was used with and without their corresponding silane (SIL) coupling agent (n = 15). After fabrication, the specimens were stored in distilled water for 3 days at room temperature, and shear bond strength was tested. RESULTS: Application of the silane-coupling agent on sandblasted densely sintered alumina did not significantly influence bond strengths with PAN. Silanization significantly improved shear bond strengths with NOR and VAR. NOR-SIL and VAR-SIL revealed the statistically highest values, with NOR-SIL showing the highest mean bond strength of all groups. CONCLUSIONS: Silanization of sandblasted densely sintered alumina had mixed effects on the applied resin cements: It had no effect on the performance of the phosphate-modified resin cement PAN, but significantly improved shear bond strength of the Bis-GMA composite resin cements VAR and NOR. NOR-SIL revealed the highest overall mean bond strength.     

Resin bond strength to densely sintered alumina ceramic

PURPOSE: The aim of this in vitro study was to investigate the resin bond strength and durability of adhesive bonding systems to densely sintered, pure aluminum oxide ceramic. MATERIALS AND METHODS: Acrylic glass tubes filled with composite resin were bonded to industrially manufactured alumina ceramic disks with an ultrasonically machined surface. Groups of 20 samples were bonded in an alignment apparatus using five different bonding methods. Subgroups of 10 bonded samples were tested for tensile strength following storage in distilled water at 37 degrees C for either 3 or 150 days. In addition, the 150-day samples were thermocycled 37,500 times. The statistical analyses were made by the Kruskal-Wallis test, followed by multiple pairwise comparison of the groups using the Mann-Whitney test. RESULTS: The mean bond strength of a bis-GMA composite resin to sandblasted alumina ceramic was relatively high after 3 days, at 20 MPa. Additional silanization or tribochemical silica coating and silanization did not enhance the bond strength (18 to 20 MPa) and failed spontaneously over long-term storage. However, using a composite resin containing a special adhesive phosphate monomer, a statistically significantly higher and durable bond strength to the sandblasted alumina ceramic surface was achieved after 3 days (50 MPa) and after 150 days of storage (46 MPa). CONCLUSION: A durable bond strength to pure alumina ceramic was achieved only by using a composite resin containing an adhesive phosphate monomer after sandblasting the ceramic surface.     

Evaluation of two dual-functional primers and a tribochemical surface modification system applied to the bonding of an indirect composite resin to metals

We evaluated the effects of two dual-functional primers and a tribochemical surface modification system on the bond strength between an indirect composite resin and gold alloy or titanium. Disk specimens (diameter, 10 mm; thickness, 2.5 mm) were cast from type 4 gold alloy and commercially pure titanium. The specimens were wetground to a final surface finish using 600-grit silicone carbide paper. The specimens were then air-dried and treated using the following four bonding systems: (1) air-abrasion with 50–70 μm alumina, (2) system 1 + alloy primer, (3) system 1 + metal link primer, and (4) tribochemical silica/silane coating (Rocatec). A light-polymerizing indirect composite resin (Ceramage) was applied to each metal specimen and polymerized according to the manufacturer’s specifications. Shear bond strengths (MPa) were determined both before and after thermocycling (4°C and 60°C for 1 min each for 20 000 cycles). The values were compared using analysis of variance, post hoc Scheffe tests, and Mann-Whitney U tests (alpha = 0.05). The strengths decreased after thermocycling for all combinations. For both gold alloy and titanium, the bond strength with air-abrasion only was statistically lower than that with the other three modification methods after thermocycling. Titanium exhibited a significantly higher value (13.4 MPa) than gold alloy (10.5 MPa) with the air. abrasion and alloy primer system. Treatment with the tribochemical system or air abrasion followed by treatment with dual-functional priming agents was found to be effective for enhancement of the bonding between the indirect composite and gold alloy or titanium.