Effect of thermocycling on the bond strength between dual-cured resin cements and zirconium-oxide ceramics

The present study evaluated the durability of bond strength between zirconia and 3 different resin cements. Thirty stabilized tetragonal zirconium-dioxide blocks were duplicated in dual-curing resin core build-up material specimens. Resin blocks were randomly luted to zirconium surfaces using 1) Clearfil Esthetic Cement (CLF), 2) RelyX Unicem Aplicap (RELX), or 3) Multilink Automix (MLA). After 24 h, half of the specimens from each of the 3 groups were loaded in tension until fracture (0.5 mm/min). The remaining half were tested after 6,000 thermal cycles (5 to 55°C). Data were analyzed using 2-way ANOVA and the Tukey test (α = 0.05). Fractographic analysis was performed using a stereomicroscope. Tensile bond strength values were significantly affected by the luting agent system employed and by thermal aging (P < 0.001). The highest tensile bond strength values in non-thermal-aged groups were observed for specimens from the RELX and CLF groups. In contrast, in the thermal-aged groups, the highest tensile bond strength values were for the MLA and RELX groups. Moreover, while thermocycling significantly affected bond strengths in the RELX and CLF groups, the mean strength of the MLA group did not significantly change after aging. There was little difference in the distribution of failure modes in any group.     

Resistance to bond degradation between dual-cure resin cements and pre-treated sintered CAD-CAM dental ceramics

Objective: To evaluate the bond stability of resin cements when luted to glass-reinforced alumina and zirconia CAD/CAM dental ceramics. Study design: Eighteen glass-infiltrated alumina and eighteen densely sintered zirconia blocks were randomly conditioned as follows: Group 1: No treatment; Group 2: Sandblasting (125 µm Al2O3-particles); and Group 3: Silica-coating (50 µm silica-modified Al2O3-particles). Composite samples were randomly bonded to the pre-treated ceramic surfaces using different resin cements: Subgroup 1: Clearfil Esthetic Cement (CEC); Subgroup 2: RelyX Unicem (RXU); and Subgroup 3: Calibra (CAL). After 24 h, bonded specimens were cut into 1 ± 0.1 mm2 sticks. One-half of the beams were tested for microtensile bond strength (MTBS). The remaining one-half was immersed in 10 % NaOCl aqueous solution (NaOClaq) for 5 h before testing. The fracture pattern and morphology of the debonded surfaces were assessed with a field emission gun scanning electron microscope (FEG-SEM). A multiple ANOVA was conducted to analyze the contributions of ceramic composition, surface treatment, resin cement type, and chemical challenging to MTBS. The Tukey test was run for multiple comparisons (p < 0.05). Results: After 24 h, CEC luted to pre-treated zirconia achieved the highest MTBS. Using RXU, alumina and zirconia registered comparable MTBS. CAL failed prematurely, except when luted to sandblasted zirconia. After NaOClaq storage, CEC significantly lowered MTBS when luted to zirconia or alumina. RXU decreased MTBS only when bonded to silica-coated alumina. CAL recorded 100 % of pre-testing failures. Micromorphological alterations were evident after NaOClaq immersion. Conclusions: Resin-ceramic interfacial longevity depended on cement selection rather than on surface pre-treatments. The MDP-containing and the self-adhesive resin cements were both suitable for luting CAD/CAM ceramics. Despite both cements being prone to degradation, RXU luted to zirconia or untreated or sandblasted alumina showed the most stable interfaces. CAL experimented spontaneous debonding in all tested groups. Key words:CAD/CAM ceramic, alumina, zirconia, resin cement, surface pre-treatment, sandblasting, silica-coating, chemical aging, bond degradation, microtensile bond strength.     

Micro-shear bond strength of dual-cured resin cement to glass ceramics.

OBJECTIVES: The aim of this study was to investigate the effects of sandblasting, etching, and a silane coupling agent on the ability of dual-cured resin cement to bond to glass ceramics designed for in indirect adhesive restoration. METHODS: A cast glass ceramic (Olympus Castable Ceramics) with a crystalline phase consisting of mica and beta-spondumene was selected as the substrate material. The glass surfaces, which were sandblasted, polished, or etched with phosphoric acid or hydrofluoric acid (HF), were bonded with a dual-cured resin cement (Panavia Fluoro Cement) using a dentin adhesive system (Clearfil SE Bond), both with and without a silane coupling agent. A micro-shear bond test was carried out to measure the bond strength of the resin cement to the glass surface. Each glass surface was bonded and tested using the shear test. In addition, surfaces with the bonding removed after the shear bond test, the adhesive interface between the glass and cement, and an etched glass surface without any bonding, were studied morphologically using scanning electron microscopy or field emission scanning electron microscopy. RESULTS: Usage of a silane coupling agent effectively raised the bond-strength values of resin cement (Fisher's PLSD, P<0.01). The effectiveness of using phosphoric acid etching to improve bonding was not clear (Fisher's PLSD, P>0.01). HF-etching for 30s seemed to over-etch the glass surface, resulting in adverse effects on bonding (Fisher's PLSD, P<0.01). SIGNIFICANCE: The micro-shear bond strength between Olympus Castable Ceramics and resin cement can be increased by the silane coupling agent used along with an acidic primer.     

Effect of curing mode on microtensile bond strength to dentin of two dual-cured adhesive systems in combination with resin luting cements for indirect restorations

This study evaluated the microtensile bond strength (microTBS) of dual-cured adhesive systems when the different components were either light activated or left in the uncured state prior to cementation of an indirect composite restoration. Occlusal dentin surfaces of 40 human third molars were flattened. The teeth were randomly assigned to 8 groups (n = 5) according to the dual-cured systems (bonding agents/resin cements) and curing modes: All Bond 2/Duolink (AB2-BISCO Inc) and Optibond Solo Plus Dual Cure/Nexus 2 (SOLO-Kerr). Resin cements were applied to pre-cured resin composite discs (2 mm thick/Z-250/3M ESPE), which were fixed to dentin surfaces containing adhesive resin in either cured (LP) or uncured states (SP). The restored teeth were light activated according to the manufacturers' instructions (LRC-XL3000/3M ESPE) or allowed to self-cure (SRC). The restored teeth were water-stored at 37 degrees C for 24 hours. They were then both mesial-distally and buccal-lingually sectioned to obtain bonded specimens (1.2 mm2). Each specimen was tested in tension at a crosshead speed of 0.6 mm/minute until failure. Data (MPa (SD)) were analyzed by two-way ANOVA and Tukey's post-hoc test (p < .05). AB2/SP exhibited higher microTBS than AB2/LP (p = .00001); however, no significant differences were noted between SOLO/LP and SOLO/SP. Results suggested that dual-cured adhesive systems were as strong or even stronger when they were left in the uncured state prior to indirect resin composite cementation.     

Effect of pulpal pressure on the microtensile bond strength of luting resin cements to human dentin

ObjectivesThe objectives of this study were to examine the effect of pulpal pressure on the microtensile bond strength (mTBS) of luting resin cements to human dentin and the permeability of dentin surfaces pre-treated with an adhesive and a self-etching primer.MethodsCylindrical composite blocks were luted with resin cements (RelyX ARC, 3M ESPE: ARC; Panavia F, Kuraray Medical Inc.: PF; RelyX Unicem, 3M ESPE: UN) in the absence or presence of simulated pulpal pressure. The application of Adper Single Bond 2 (3M ESPE) and ED primer 2.0 (Kuraray) was performed under 0 cm H₂O. After each resin cement was applied, the pulpal pressure group was subjected to 20 cm H₂O of hydrostatic pressure for 10 min during the initial setting period. Testing for mTBS was performed on 0.9 mm × 0.9 mm sectioned beams after 24 h water-storage. Scanning electron microscopy was performed to investigate the fractured surfaces after mTBS testing and additional dentin surfaces that were treated by an etchant, ED primer 2.0 and UN. Fluid permeability was measured on dentin surfaces that were applied with Adper Single Bond 2 and ED primer 2.0.ResultsApplication of pulpal pressure reduced mTBS significantly in groups ARC and PF. Porous bonding interfaces due to water permeability through the cured adhesive were observed on fractured surfaces. Dentin surfaces that were applied with the adhesive and the primer were more permeable than smear layer-covered dentin. The mTBS of UN was significantly lower than ARC and PF regardless of the absence/presence of pulpal pressure.SignificanceFluid permeation during the initial setting period deteriorated the bonding quality of resin cements.     

Effect of activation mode of dual-cured resin cements and low-viscosity composite liners on bond strength to dentin

OBJECTIVES: The aim of this study was to investigate the influence of the activation mode of dual-cured resin cements and application of low-viscosity composite liners over self-primed dentin on bond strength (BS) of dentin-bonding agents (DBA). METHODS: Three DBA (Single Bond; Prompt L-Pop and Clearfil SE Bond), their respective resin cements (RelyX ARC and Panavia F) and two low-viscosity composites (Filtek Flow and Protect Liner F) were tested. After removing the buccal enamel surfaces of 25 bovine incisors, each flat dentin surface was sectioned longitudinally and divided into two similar parts. The dentin surfaces were wet-abraded with 600-grit SiC paper and randomly divided into 10 groups. Experimental groups comprised the use of DBA and their respective dual-cured resin cements, with or without light-activation of resin cements. The low-viscosity resin was used only for the self-etching systems, Prompt L-Pop and Clearfil SE Bond. Three resin cement cylinders (0.5mm high and 0.75mm diameter) were built on each bonded dentin surface, using a tygon tubing mold. After water storage for 24h, specimens were subjected to micro-shear testing. Data were statistically analyzed by two-way ANOVA and Tukey test. RESULTS: Light-activation of resin cements resulted in significantly higher BS for all DBA versus groups in which the resin cements were allowed to self-cure. The low-viscosity composite application increased the BS only for Prompt L-Pop. CONCLUSIONS: The bond strength of resin cements to dentin is reduced if light-activation is not employed. The use of a low-viscosity composite liner resulted in improved bond strength only for the single-step self-etching adhesive.     

树脂粘结剂与瓷表面处理对全瓷粘结微拉伸强度的影响

目的 研究3种树脂粘结剂配合2种瓷表面处理方法对全瓷粘结微拉伸强度的影响.方法 制作60个体积为5mm×6mm×8mm瓷试件(Empress Ⅱ),抛光后分成两组:对照组和HF SIL组(5%氢氟酸酸蚀20秒,硅烷处理1分钟).分别采用3种树脂粘结剂(RelyX Unicem, Variolink或Panavia F)与复合树脂粘结,37℃保存7天,切割成接触面积为1.0mm2的75个柱形体.试件经热循环(5℃～55℃循环3000次)后,测量粘结微拉伸强度(uTBS).结果 表面处理因素有重要意义(HF SIL组>对照组).对照组中Rely X Unicem的uTBS明显高于Variolink和Panavia F.HF SIL组中经RelyX Unicem和Variolink的uTBS明显高于Panavia F.结论 无论使用何种树脂粘结剂,在粘结前进行酸蚀和硅烷处理都是必要的.     

Effect of temporary cements on the microtensile bond strength of self-etching and self-adhesive resin cement

Objective. The aim of this study was to evaluate the microtensile bond strength (µTBS) of self-etching and self-adhesive resin cement systems to dentin affected by the presence of remnants of either eugenol-containing or eugenol-free temporary cements. Materials and methods. Thirty extracted teeth were obtained and a flat dentin surface was exposed on each tooth. Acrylic blocks were fabricated and cemented either with one of two temporary cements, one zinc oxide eugenol (ZOE) and one eugenol free (ZOE-free), or without cement (control). After cementation, specimens were stored in water at 37°C for 1 week. The restorations and remnants of temporary cements were removed and dentin surfaces were cleaned with pumice. Resin composite blocks were cemented to the bonded dentin surfaces with one of two resin cements, either self-etching (Panavia F 2.0) or self-adhesive (RelyX U-100). After 24 h, the specimens were sectioned to obtain beams for submission to µTBS. The fracture mode was evaluated under a stereoscopic loupe and a scanning electron microscope (SEM). Data from µTBS were submitted to two-way repeated-measure ANOVA and the Tukey test (alpha = 0.05). Results. The cross-product interaction was statistically significant (p < 0.0003). The presence of temporary cements reduced the bond strength to Panavia self-etching resin cements only (p < 0.05). Fracture occurred predominantly at the dentin–adhesive interface. Conclusions. The presence of eugenol-containing temporary cements did not interfere in the bond strength to dentin of self-adhesive resin cements.     

Bond strength of dual-cured resin cements to human teeth

PURPOSE: This study evaluated the bond strength of four commercial resin luting cements to enamel and superficial dentin, using a second-generation laboratory composite. MATERIALS AND METHODS: Forty teeth were embedded in acrylic: 20 had superficial dentin exposed; 20 had enamel exposed. Each group was divided into four subgroups (n = 5) to be bonded with Variolink II, Dual Cement, 2-bond-2, and Permalute System, using an inverted, truncated cone of pre-cured Artglass that was placed over the resin cement with a load of 2 N for 2 seconds. Specimens were stored at 37 degrees C in 100% relative humidity for 24 hours before being tested for tensile bond strength (MPa). Data were analyzed using a two-way analysis of variance. Tukey-Kramer intervals for comparisons among resin cements and bonding substrates were calculated at a .05 significance level. RESULTS: Significant differences were found among resin cements. Variolink II had statistically higher bond strength values for both substrates than the rest of the cements evaluated. When bonding was to enamel, all failures were cohesive in the composite, and when bonding was to dentin, some adhesive failures occurred at the resin cement-dentin interface. Permalute System had higher bond strengths than 2-bond-2 and Dual Cement when bonded to enamel. CONCLUSIONS: Variolink II and Permalute had statistically different bond strengths to enamel and dentin. Variolink II showed statistically higher values for dentin bonding than the other cements. Use of Variolink II and Permalute resulted in statistically higher bond strengths than the other two cements.     

Influence of different drying methods on microtensile bond strength of self-adhesive resin cements to dentin

Objective. This study investigated the effect of different drying methods of dentin surface on the bonding efficacy of self-adhesive resin cements (SRCs). Materials and methods. Three SRCs (RelyX U200, RU; Maxcem Elite, ME; and BisCem, BC) and one resin-modified glass ionomer cement (RelyX Luting 2, RL) were used. The characteristics of the materials were evaluated using thermogravimetric analysis and surface roughness and contact angle measurements. Human dentin surfaces were finished with 600-grit silicon carbide paper and assigned to three groups according to these drying methods: ethanol dehydration, drying by waiting for 10 s after blot-drying and blot-drying. The four cements were used for luting composite overlays to the dried dentin. After 24 h storage at 37°C and 100% relative humidity, stick-shaped specimens with a cross-sectional area of 0.8 mm² were prepared and stressed to failure in tension at a crosshead speed of 0.5 mm/min (n = 27). Failure modes of fractured specimens were assessed by optical and scanning electron microscopy. Results. RL was the most hydrophilic, followed by BC and ME and then RU. All the luting cements luted to ethanol-dehydrated dentin showed zero bond strengths. For the three SRCs, drying by waiting produced higher microtensile bond strengths than blot-drying. RU showed the best bonding performance in the above two dentin conditions. RL showed significantly higher bond strength in blot-drying condition than in drying-by-waiting (p < 0.001). Conclusions. This study suggests that dentin surface moisture has a crucial effect on the bond strength of SRCs.     

Shear bond strength of composite resin cements to lithium disilicate ceramics

The aim of this study was to evaluate the shear bond strength of different commercial composite resin cement systems to lithium disilicate all-ceramic substrate. Five adhesive resin cement systems Panavia 21 and Panavia F (Kuraray), Variolink 2 (Ivoclar-Vivadent), RelyX Unicem Applicap and RelyX ARC (3M ESPE) were used on all-ceramic (IPS Empress 2; Ivoclar-Vivadent) substrate. Shear bond strength of adhesive resin cement to substrate was tested after thermocycling, or without thermocycling (n = 10). Substrate surfaces of the specimen after loading were SEM microscopically examined. The highest bond strengths in water stored conditions were obtained with RelyX ARC (28.7 +/-3.9 MPa), while in thermocycled conditions the highest bonding values were obtained with Variolink 2 (23.2 +/- 7.5 MPa). The lowest values in both water stored (5.8 +/- 4.0 MPa) and thermocycled (2.4 +/- 2.9 MPa) conditions were obtained with Panavia 21. Shear bond strengths appeared to be affected significantly by thermocycling (anova, P < 0.05). It was concluded that there were significant differences between the bond strengths of adhesive resin cements to lithium disilicate substrate.     

Effect of dentin pretreatment and curing mode on the microtensile bond strength of self-adhesive resin cements

PURPOSEThe aim was to evaluate the effect of curing mode and different dentin surface pretreatment on microtensile bond strength (µTBS) of self-adhesive resin cements.RESULTSFor G-CEM LinkAce cement groups, polyacrylic acid pretreatment showed the highest µTBS in the self-cured group. In the light-cured group, no significant improvements were observed according to the dentin surface pretreatment. There were no significant differences between curing modes. Both dentin surface pretreatment methods helped to increase the µTBS of RelyX U200 resin cement significantly and degree of pretreatment effect was similar. No significant differences were found regarding curing modes except control groups. In the comparisons of two self-adhesive resin cements, all groups within the same pretreatment and curing mode were significantly different excluding self-cured control groups.CONCLUSIONSelecting RelyX U200 used in this study and application of dentin surface pretreatment with EDTA and polyacrylic acid might be recommended to enhance the bond strength of cement to dentin.     

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).     

Influence of matrix metalloproteinase synthetic inhibitors on dentin microtensile bond strength of resin cements

This study evaluated the effect of dentin pretreatment with 2% chlorhexidine (CHX) or 24% ethylenediamine tetra-acetic acid gel (EDTA) on the dentin microtensile bond strength (μTBS) of resin cements. Composite blocks were luted to superficial noncarious human dentin (n=10) using two resin cements (RelyX ARC [ARC] and RelyX U100 [U100]) and three dentin pretreatments (without pretreatment-control, CHX, and EDTA). CHX was applied for 60 seconds on the acid-etched dentin in the ARC/CHX group, and for the same time on smear layer-covered dentin in the U100/CHX group. EDTA was applied for 45 seconds on smear-covered dentin in the U100/EDTA group, and it replaced phosphoric acid conditioning in the ARC/EDTA group for 60 seconds. After storage in water for 24 hours, specimens were prepared for microtensile bond strength testing. The results were submitted to two-way analysis of variance (ANOVA) followed by Tukey test. ARC produced significantly higher μTBS (p<0.05) compared to the U100, except when EDTA was used. For ARC, no pretreatment and CHX produced higher μTBS than EDTA. For U100, EDTA produced higher μTBS; no statistical difference occurred between CHX pretreatment and when no pretreatment was performed. While CHX did not affect immediate dentin bond strength of both cements, EDTA improved bond strength of U100, but it reduced dentin bond strength of ARC.