Mechanical Properties of Dual-Cured Resin Luting Agents for Ceramic Restoration

PURPOSE: The aim of the present study was to evaluate mechanical properties, including surface hardness, flexural strength, and flexural modulus, of two dual-cured resin luting agents [Clearfil Esthetic Cement (CEC) and Variolink II (VLII)] irradiated through four thicknesses of leucite ceramics (0, 1, 2, and 3 mm) and to evaluate their shear bond strength to zirconia ceramic (Cercon) using each ceramic primer. MATERIALS AND METHODS: Knoop hardness was measured on a thin layer of resin luting agent on the ceramic surface. Three-point bending tests were performed after 24 hours of storage at 37 degrees C. Two differently shaped zirconia ceramic specimens with or without sandblasting with alumina were treated with each primer. The specimens were then cemented together with each resin luting agent. Half of the specimens were stored in water at 37 degrees C for 24 hours and the other half were thermocycled 5000 times. RESULTS: VLII revealed statistically higher Knoop hardness and flexural modulus than CEC for each thickness of ceramic. No significant differences in flexural strength were observed between VLII and CEC for each ceramic spacer. Reduction of the mechanical properties with increase of ceramic thickness varied for each property; however, these properties were similar in the two materials. Blasting with alumina was significantly effective for increasing shear bond strength of both resin luting agents before and after thermal cycling. The use of Clearfil Ceramic Primer showed the highest shear bond strength and maintained bond durability after 5000 thermocycles. CONCLUSION: Mechanical properties of CEC dual-cured resin luting agent appear adequate for ceramic restorations.     

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.     

Effects of alumina-blasting and adhesive primers on bonding between resin luting agent and zirconia ceramics

This study evaluated the effect of alumina-blasting and three commercial adhesive primers on the shear bond strength of a dual-cured resin luting agent to zirconia ceramics. Two different-sized zirconia ceramic specimens were treated with or without alumina-blasting and then treated with one of three adhesive primers. Subsequently, specimens were cemented together with Linkmax HV (GC). Half of the specimens were stored in water at 37 degrees C for 24 hours and the other half thermocycled 10,000 times before shear bond strength testing. For groups treated with either alumina-blasting or primer, shear bond strength significantly decreased after thermal cycling. For groups treated with both alumina-blasting and one of the three primers, there were no significant differences in shear bond strength before and after thermal cycling (p<0.05). It was thus concluded that the application of each of the three adhesive primers following alumina-blasting was effective for strong bonding of resin luting agent to zirconia ceramics.     

2种粘结剂及粘结方法对CAD/CAM全瓷冠抗折强度的影响

目的 研究不同粘结方法及冷热循环对Cerec全瓷冠粘结后抗折强度的影响。 方法 选择离体前磨牙80颗,进行Cerec全瓷冠预备及制作。随机分为1~4组,每组20颗,分别使用Variolink N树脂粘结剂+硅烷偶联剂粘结、Variolink N树脂粘结剂粘结、Bisco Choice TM 2树脂粘结剂＋硅烷偶联剂粘结、Bisco Choice TM 2树脂粘结剂粘结;每组再分为A、B小组,分别不进行和进行冷热循环。8组试件均用万能力学实验机测试其全瓷冠最大抗折裂强度,观察所有标本粘结破坏形式;进行统计分析。 结果 使用Variolink N树脂粘结剂+硅烷偶联剂组粘结的Cerec全瓷冠抗折裂强度最高;全瓷冠抗折强度A组(非冷热循环)高于B组。差异有统计学意义(P<0.05)。 结论 双重固化树脂粘结系统是牙科长石质陶瓷粘结的理想选择,可以获得较高的抗折裂强度。冷热循环降低Cerec全瓷冠抗折裂强度。     

Bonding of a mica-based castable ceramic material with a tri-n-butylborane-initiated adhesive resin

SUMMARY Adhesive bonding of a mica-based castable ceramic material (Olympus Castable Ceramics, OCC) was evaluated in vitro with the use of a silane primer in conjunction with an adhesive luting material. The primer contained a silane coupler and 4-methacryloxyethyl trimellitate anhydride (4-META), while the methyl methacrylate (MMA)-based luting agent was initiated with a tri-n-butylborane derivative (TBB) and contained 4-META (4-META/MMA-TBB resin). Ceramic specimens were sanded with No. 600 silicon carbide paper followed by blasting with alumina and/or etching with ammonium bifluoride. The specimens were bonded with various combinations and shear bond strengths were determined. Both priming and alumina blasting enhanced the bond between 4-META resin and OCC. Although etching with ammonium bifluoride roughened the ceramic surface, this procedure did not improve the bond strength. Electron probe microanalysis of the ceramic surface revealed a decrease in silicon and aluminium elements after etching with ammonium bifluoride.     

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.     

Adhesive bonding of titanium with a methacrylate–phosphate primer and self-curing adhesive resins

SUMMARY The adhesive bonding of titanium was evaluated with the use of a metal primer and three types of self curing luting agent. The primer contained 10-methacryloyloxydecyl dihydrogen phosphate (MDP). One luting agent was a composite material that contained the MDP monomer in its liquid part. The other luting agent was based on methyl methacrylate (MMA), initiated with tri-n-butylborane derivative (TBB), and contained 4-methacryloyloxyethyl trimellitate anhydride (4-META). The MMA-TBB resin without 4-META was used for the control. Pure titanium metal specimens were bonded with various combinations. Shear bond strengths were determined after repeated thermocycles in water. Both MDP and 4-META were effective in bonding titanium. The decrease in bond strength was minimum when the titanium was primed with MDP and then bonded with the TBB-initiated resins.     

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.     

Effects of two silane coupling agents, a bonding agent, and thermal cycling on the bond strength of a CAD/CAM composite material cemented with two resin luting agents

STATEMENT OF PROBLEM: Surface treatment of CAD/CAM-generated composite material is important for a strong bond of resin luting agents to composite material. Purpose. This study evaluated the shear bond strengths of 2 dual-cured resin luting agents to a CAD/CAM composite material and the effect of silane coupling agent and bonding resin on the bond strength. MATERIAL AND METHODS: Rectangular- and disk-shaped CAD/CAM composite materials were untreated or treated with 1 of the 2 silane coupling agents or bonding resin and then cemented together with 1 of the 2 dual-cured resin luting agents. Half of the specimens were stored in water at 37 degrees C for 24 hours, the other half thermocycled 50,000 times before shear bond strength testing. Shear bond strengths were measured with a servohydraulic mechanical testing machine, and results were analyzed with 2-way analysis of variance. RESULTS: Surface treatment by silane coupling agent improved the shear bond strength when compared with nontreatment. Specimens treated with bonding resin showed significantly greater shear bond strength than the untreated groups. However, all specimens had the same adhesive failures at the composite-luting agent interface as untreated groups. When the CAD/CAM composite material was treated with 1 of the 2 silane coupling agents, no significant differences in bond strength were noted between water storage alone and after 50,000 thermocycles. For the 2 groups treated with bonding resin or silane coupling agent and cemented with 1 of the 2 dual-cured resin luting agents, there were significant increases in bond strength after 50,000 thermocycles, compared with specimens that were not subjected to thermal cycling. On the other hand, for the 2 untreated groups, there were significant decreases in bond strength after thermocycling. After 50,000 thermocycles, all specimens treated with silane coupling agent and then cemented with 1 of the 2 resin luting agents showed cohesive failures within the composite material. CONCLUSION: The application of a silane coupling agent to the CAD/CAM composite surface provided the highest bond strength between the resin luting agent and composite after long-term thermal cycling.     

纳米硅涂层对玻璃渗透氧化铝陶瓷粘结强度的影响

目的：探讨利用溶胶凝胶法进行纳米硅涂层表面改性对玻璃渗透氧化铝陶瓷粘结强度的影响。方法：3组In-Ceram氧化铝瓷块分别施以“喷砂（P组）”、“喷砂＋硅烷偶联（PO组）”、“喷砂＋纳米硅涂层＋硅烷偶联（PTO）组）”的表面处理。制作陶瓷／复合树脂粘结体,室温下置蒸馏水中浸泡24h,微拉伸法测试各组试件粘结强度。结果：P组与PO组粘结强度较弱且无明显差异（P=0．797）,PTO组的粘结强度明显高于其他组（P〈0．05）。结论：通过溶胶凝胶法在喷砂表面制备纳米硅涂层后应用硅烷偶联剂可以显著提高In-Ceram氧化铝陶瓷的粘结强度。     

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).     

Evaluation of thiouracil-based adhesive systems for bonding cast silver-palladium-copper-gold alloy

This study aimed to evaluate the effect of adhesive systems based on a thiouracil monomer on bonding to silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy (Castwell M.C.12). Disk specimens were cast from the alloy and then air-abraded with alumina. The disks were bonded using six bonding systems selected from four primers and three luting materials. Shear bond strengths were determined both before and after thermocycling. Bond strength varied from 2.7 MPa to 32.0 MPa. Three systems based on a thiouracil monomer (MTU-6) showed durable bonding to the alloy, with post-thermocycling bond strengths of 22.4 MPa for the Metaltite (MTU-6) primer and Super-Bond, a tri-n-butylborane (TBB) initiated resin, 9.0 MPa for the Multi-Bond II resin, and 8.1 MPa for the Metaltite and Bistite II system. It can be concluded that a combination of thiouracil-based primer and TBB initiated resin is effective for bonding Ag-Pd-Cu-Au alloy.     

Influence of ceramic thickness and polymerization mode of a resin luting agent on early bond strength and durability with a lithium disilicate-based ceramic system

STATEMENT OF PROBLEM: Attenuation of polymerization light energy by translucent all-ceramic materials may result in insufficient polymerization of underlying resin luting agents and inadequate early bond strength and durability. There is little information regarding the selection of an appropriate polymerization mode for cementing translucent all-ceramic restorations. PURPOSE: The purpose of this study was to evaluate the influence of ceramic thickness and polymerization mode on the early bond strength and bond durability of a lithium disilicate-based ceramic system. MATERIAL AND METHODS: The occlusal surfaces of 120 extracted, intact, human third molars were sectioned to expose a flattened area of dentin. The surface was etched with 32% phosphoric acid, and a single-step adhesive (One-Step) was applied to the etched dentin surfaces. Ceramic specimens (Empress 2), 6 mm in diameter and 1 mm, 1.5 mm, or 2 mm thick (n=40 per group), were fabricated using fluoropolymer resin matrixes. Each specimen was ground flat. Following hydrofluoric acid etching and silane treatment, ceramic discs of each thickness were further divided into 2 groups (n=20 per group) and bonded to the dentin surfaces with a dual-polymerized resin luting agent (Illusion), either with a catalyst (dual polymerization) or without a catalyst (light polymerization). A shear bond test was performed after 10 minutes (n=10) or after 24 hours following 1000 thermal cycles between 5 degrees C and 55 degrees C and a dwell time of 30 seconds (n=10). Debonded dentin surfaces were examined with SEM. The data were analyzed with 3-way analysis of variance (ANOVA) (alpha=.05). RESULTS: The shear bond strengths ranged between 13.2 +/- 4.1 MPa and 15.9 +/- 2.0 MPa. Three-way ANOVA revealed that ceramic thickness, polymerization mode, storage time, or combinations of these parameters did not influence shear bond strength. The location of failure for all specimens was adhesive, between the dentin surface and bonding agent. CONCLUSION: Both light polymerization and dual polymerization provided similar early shear bond strengths for the lithium disilicate-based ceramic system (Empress 2). The bond strength was not dependent on the thickness of the ceramic material tested. Durability of the bond was similar for both of the polymerization modes.     

Adhesive bonding of a lithium disilicate ceramic material with resin-based luting agents

This study evaluates the bonding characteristics of a lithium disilicate-based ceramic material (IPS Empress 2). Two sizes of disk specimens of the material were made, and three groups of disk pairs were separately surface-prepared using three techniques; etching with phosphoric acid, etching with hydrofluoric acid, and air-abrasion with alumina. Each group was further divided into four sub-groups; group (i) was bonded with the Variolink II composite, (ii) was treated with the Monobond-S silane primer and bonded with the Variolink II composite, (iii) was bonded with the Super-Bond acrylic adhesive and (iv) was treated with the Porcelain Liner M silane primer and bonded with the Super-Bond acrylic adhesive. Shear bond strengths were determined before and after 100 000 thermocycles. Bond strength varied from 10.6 to 71.5 MPa before thermocycling, whereas post-thermocycling bond strength ranged from 0 to 61.2 MPa. Among the three surface preparations, hydrofluoric acid etching (HF) was most effective in enhancing bond strength of both luting materials, especially for unsilanized specimens. Application of the silane primer elevated bond strength of both luting agents regardless of surface preparation method. It can be concluded, for both luting agents, that durable bond to the Empress 2 ceramic material can be achieved through the combined application of HF and the proprietary silane primer.     

Microshear bond strength of resin bonding systems to machinable ceramic with different surface treatments

PURPOSE: The bond strength and bond durability of two high-viscosity dual-curing resin luting agents with different surface treatments of ceramic were investigated. MATERIALS AND METHODS: GN-I machinable ceramic surfaces were treated with 37% phosphoric acid for 30 s (PA), 5% hydrofluoric acid for 5 s (HF-5), 10 s (HF-10), or 30 s (HF-30), or blasting with 50-microm Al2O3 for 10 s (AB). The roughness of the ceramic surface was measured. Treated ceramic surfaces were bonded with three resin bonding systems (RBS): Ceramic Primer/LinkmaxHV (CP/LMHV), Monobond S/VariolinkIIHV (MBS/VLIIHV), or MBS/Heliobond/VLIIHV (MBS/HB/VLIIHV). A microshear test was used to measure the bond strength after 24 h (TC 0) and subsequent thermocycling (TC 10,000 at 4 degrees C and 60 degrees C). ANOVA was performed for statistical analysis, with significance set at p < 0.05. RESULTS: For three RBSs, bond strength at TC O was not affected, regardless of ceramic surface treatment (p > 0.05). All combined groups of ceramic surface treatment and resin bonding system decreased after 10,000 thermal cycles, especially groups treated with alumina blasting and bonded with each of three RBSs (p < 0.05). MBS/HB/VLIIHV with each surface treatment did not improve the bond strength and durability compared with MBS/VLIIHV. CONCLUSION: CP/LMHV and MBS/VLIIHV obtained sufficient bond strength and bond durability to GN-I machinable ceramic by only cleaning with PA; the application of HB may not be necessary.     

Effect of primers on bonding agent polymerization

The aim of the present study was to evaluate the effect of primers on the polymerization of bonding agent. We measured the degree of conversion (radical production) and mechanical properties (surface hardness and direct tensile strength) of various adhesives/primers mixed at different ratios and the effect of varying the visible-light curing time. With and without primer treatment, the tensile bond strength of adhesive resin to micacious glass ceramic and human enamel was measured. After the tensile bond test, using the Image Capture System, the failure patterns of adhesive resin bonded to micacious glass-ceramic were analysed. The results show that the mixtures containing the higher amounts of primer yielded a lower degree of conversion and inferior mechanical properties when compared with the mixtures containing a lower proportion of primer, except in the experimental bonding system. The adhesive/primer mixtures inhibited free radical polymerization. The value for the Knoop hardness number and the direct tensile strength of the adhesive/primer mixtures were significantly decreased compared with those of the adhesive bonding agent alone with no primer added. The tensile bond strength of adhesive resin bonded to micacious glass-ceramic or human enamel without primer treatment was significantly greater than that of adhesive resin with primer treatment in certain cases. Most of the fractures of ceramic surfaces were cohesive (within resins) and/or interface (at the ceramic surface) failure.     

Zirconate coupling agent for bonding resin luting cement to pure zirconium

PURPOSE: To evaluate the shear bond strengths of two dual-cured resin luting cements to pure zirconium and the effect of zirconate coupling agent on the bond strength. METHODS: The two different-shaped pure zirconium specimens (99.9%) were untreated or treated with one of the four primers including zirconate coupler and then cemented together with one of the two dual-cured resin luting cements. Half of the specimens were stored in water at 37 degrees C for 24 hours and the other half thermocycled 20,000 times before shear bond strength testing. RESULTS: Regardless of the resin luting cement and thermocycling, specimens treated with the mixture of zirconate coupler and resin bonding agent showed the highest shear bond strength among the five treatments. Surface treatment with the mixture of zirconate coupler and resin bonding agent showed significantly greater shear bond strength compared with other treatments at 20,000 thermocycles. The application by the mixture of zirconate coupler and resin bonding agent on the pure zirconium metal surface appears to be effective for bonding between zirconium and dual-cured resin luting cements.     

Effects of a metal etchant and two primers on resin bonding durability to titanium

The purpose of this study was to investigate the efficacy of an etchant in titanium bonding. The aqueous etchant consisted of 0, 5, or 10 wt% ammonium hydrogen fluoride (AHF) in combination with 0, 0.03, 0.3, or 3 wt% cupric chloride (CC). The two primers used were a phosphate-methacrylate primer and a thiophosphate-methacrylate primer, and two self-curing resins (Super-Bond C&B and MT) were employed as luting agents. Disk specimens were cast with a commercially pure titanium. The surface was air-abraded with 50 microm alumina, etched for 10 s, rinsed with water, and then air-dried. The primer was applied to the bonding area (5 mm in diameter), and an acrylic rod was bonded to the specimen with the luting agent. Shear bond strengths were evaluated after 24 h of water storage and following 10,000 thermocycles (4 degrees C and 60 degrees C). The post-thermocycling bond strength was significantly increased with each of the two primers compared with the unprimed controls. The etchant containing 5 wt% AHF and 0.3 wt% CC further increased their durability, and microscopic observation revealed that innumerable submicron crystals were created on the etched specimen. The present results suggest that the chemical etching improved the resin bonding durability to titanium in combination with the primer used.     

Dentin bond strength and marginal adaptation: direct composite resins vs ceramic inlays.

The aim of this in vitro study was to compare the dentin bond strength and marginal adaptation of directly and indirectly inserted restorations. A conically modified push-out test was designed to consider polymerization shrinkage and facilitate inlay placement. A total of 260 cavities were prepared into disks of freshly extracted human third molars and filled with direct composite resins or with adhesively luted ceramic inlays. Dentin adhesives of the third--(with self-etching primer: ART Bond, Syntac Classic), fourth--(with total etching: Scotchbond Multi-Purpose Plus), and fifth-generation (one-bottle adhesives: Syntac Single Component, Prime & Bond 2.1) were used in combination with one hybrid composite (Tetric) or luting composite (Variolink Low). Control groups did not use an adhesive. Polymerization of the bonding agent was carried out prior to insertion of the filling/inlay or afterwards simultaneously with the composite/luting composite. The thickness of the adhesive layer and luting composite was recorded, and after 7 days of storage and 24 hours of thermocycling (1150 cycles) replicas were made and extrusion testing performed. Fracture modes were determined and replicas were examined regarding marginal adaptation using SEM (X200 magnification). Precuring of the bonding resin increased dentin bond strength independent of the material combination or insertion mode (P < 0.05). In general, third- and fourth-generation dentin adhesives produced better results in bond strength and marginal adaptation than one-bottle systems (P < 0.05). In the third generation, ART Bond achieved significantly higher push-out values than Syntac (P < 0.05), but no better marginal adaptation. Cohesive fractures within the dentin were only observed in the inlay groups with precured resin. Precuring of the bonding resin is an important factor for both direct and indirect restorations. Nevertheless, precuring of the bonding resin prior to insertion of adhesive inlays cannot be recommended clinically, because the 120-micron luting spaces were too large. In simulated cavities, direct composite fillings with precuring achieved bond strengths similar to inlays without precuring. One-bottle adhesive systems performed poorly compared with multi-step adhesives of the third and fourth generation.     

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.