Bond strength durability of direct and indirect composite systems following surface conditioning for repair

Purpose: This study evaluated the effect of surface conditioning methods and thermocycling on the bond strength between a resin composite and an indirect composite system in order to test the repair bond strength. Materials and Methods: Eighteen blocks (5 x 5 x 4 mm) of indirect resin composite (Sinfony) were fabricated according to the manufacturer's instructions. The specimens were randomly assigned to one of the following two treatment conditions (9 blocks per treatment): (1) 10% hydrofluoric acid (HF) for 90 s (Dentsply) + silanization, (2) silica coating with 30-Ìm SiOx particles (CoJet) + silanization. After surface conditioning, the bonding agent was applied (Adper Single Bond) and light polymerized. The composite resin (W3D Master) was condensed and polymerized incrementally to form a block. Following storage in distilled water at 37°C for 24 h, the indirect composite/resin blocks were sectioned in two axes (x and y) with a diamond disk under coolant irrigation to obtain nontrimmed specimens (sticks) with approximately 0.6 mm2 of bonding area. Twelve specimens were obtained per block (N = 216, n = 108 sticks). The specimens from each repaired block were again randomly divided into 2 groups and tested either after storage in water for 24 h or thermocycling (6000 cycles, 5°C to 55°C). The microtensile bond strength test was performed in a universal testing machine (crosshead speed: 1 mm/min). The mean bond strengths of the specimens of each block were statistically analyzed using two-way ANOVA (α = 0.05). Results: Both surface conditioning (p = 0.0001) and storage conditions (p = 0.0001) had a significant effect on the results. After 24 h water storage, silica coating and silanization (method 2) showed significantly higher bond strength results (46.4 ± 13.8 MPa) than that of hydrofluoric acid etching and silanization (method 1) (35.8 ± 9.7 MPa) (p < 0.001). After thermocycling, no significant difference was found between the mean bond strengths obtained with method 1 (34.1 ± 8.9 MPa) and method 2 (31.9 ± 7.9 MPa) (p > 0.05). Conclusion: Although after 24 h of testing, silica coating and silanization performed significantly better in resin-resin repair bond strength, both HF acid gel and silica coating followed by silanization revealed comparable bond strength results after thermocycling for 6000 times.

Microtensile bond strength of a repair composite to leucite-reinforced feldspathic ceramic

The purpose of this study was to evaluate the microtensile bond strength of a repair composite resin to a leucite-reinforced feldspathic ceramic (Omega 900, VITA) submitted to two surface conditionings methods: 1) etching with hydrofluoric acid + silane application or 2) tribochemical silica coating. The null hypothesis is that both surface treatments can generate similar bond strengths. Ten ceramic blocks (6x6x6 mm) were fabricated and randomly assigned to 2 groups (n=5), according to the conditioning method: G1- 10% hydrofluoric acid application for 2 min plus rinsing and drying, followed by silane application for 30 s; G2- airborne particle abrasion with 30 μm silica oxide particles (CoJet-Sand) for 20 s using a chairside air-abrasion device (CoJet System), followed by silane application for 5 min. Single Bond adhesive system was applied to the surfaces and light cured (40 s). Z-250 composite resin was placed incrementally on the treated ceramic surface to build a 6x6x6 mm block. Bar specimens with an adhesive area of approximately 1 ± 0.1 mm2 were obtained from the composite-ceramic blocks (6 per block and 30 per group) for microtensile testing. No statistically significant difference was observed between G1 (10.19 ± 3.1 MPa) and G2 (10.17 ± 3.1 MPa) (p=0.982) (Student's t test; á = 0.05). The null hypothesis was, therefore, accepted. In conclusion, both surface conditioning methods provided similar microtensile bond strengths between the repair composite resin and the ceramic. Further studies using long-term aging procedures should be conducted.

Durability of the bond strength of self-adhesive resin cements to human dentin

This study subjected two self-adhesive resin cements and two conventional resin cements to dry and aging conditions, to compare their microtensile bond strengths (MTBS) to dentin. Using four different luting systems (n = 10), 40 composite resin blocks (each 5x5x4 mm) were cemented to flat human crown dentin surfaces. The specimens were stored in water for 24 hours (37°C), at which point each specimen was sectioned along two axes to obtain beams that were divided randomly into two groups: dry samples, which were tested immediately, and samples that were subjected to accelerated aging conditions (12, 000 thermocycles followed by storage for 150 days). The μTBS results were affected significantly by the luting system used (P < 40001). Only the μTBS of Rely-X Unicem was reduced significantly after aging; the μTBS remained stable or increased for the other self-adhesive resin cement and the two conventional cements.

Influence of desensitizing agents on the microshear bond strength of adhesive systems to dentin.

The aim of this study was to evaluate the effect of desensitizing agents on the micro-shear bond strength of adhesive systems to dentin. Forty bovine teeth were divided into 8 groups (n=5): G1--Single Bond (SB); G2--GH.F + SB; G3-- Desensibilize + SB; G4--essensiv + SB; G5 --ingle Bond 2 (SB2); G6--H.E + SB2; G7--esensibilize + SB2; G8--Dessensiv + SB2. In all of the groups, the desensitizing agents were applied after phosphoric acid etching and before the dentin adhesive application. Z250 composite resin tubes were bonded on the treated surface. After 24 hours, the teeth were tested in a universal machine. Data were submitted to ANOVA and Tukey's test (5%). The results showed that the groups where Desensibilize and Dessensiv were applied exhibited smaller bond strength values.

Effect of surface treatments on the bond strength of a resin cement to commercially pure titanium

Investigation of the effectiveness of surface treatments that promote a strong bond strength of resin cements to metals can contribute significantly to the longevity of metal-ceramic restorations. This study evaluated the effect of surface treatments on the shear bond strength (SBS) of a resin cement to commercially pure titanium (CP Ti). Ninety cast CP Ti discs were divided into 3 groups (n=30), which received one of the following airborne-particle abrasion conditions: (1) 50 μm Al2O3 particles; (2) 30 μm silica-modified Al2O3 particles (Cojet Sand); (3) 110 μm silica-modified Al2O3 particles (Rocatec). For each airborne-particle abrasion condition, the following post-airborne-particle abrasion treatments were used (n=10): (1) none; (2) adhesive Adper Single Bond 2; (3) silane RelyX Ceramic Primer. RelyX ARC resin cement was bonded to CP Ti surfaces. All specimens were thermally cycled before being tested in shear mode. Failure mode was determined. The best association was Rocatec plus silane. All groups showed 100% adhesive failure. There were combinations that promote higher SBS than the protocol recommended by the manufacturer of RelyX ARC.

Bond strength of a composite resin to an adhesive luting cement

This study evaluated the influence of surface treatment on the shear bond strength of a composite resin (CR), previously submitted to the application of a temporary cement (TC), to an adhesive luting cement. Eight-four CR cylinders (5 mm diameter and 3 mm high) were fabricated and embedded in acrylic resin. The sets were divided into 6 groups (G1 to G6) (n=12). Groups 2 to 6 received a coat of TC. After 24 h, TC was removed and the CR surfaces received the following treatments: G2: ethanol; G3: rotary brush and pumice; G4: air-abrasion; G5: air-abrasion and adhesive system; G6: air-abrasion, acid etching and adhesive system. G1 (control) did not receive TC or any surface treatment. The sets were adapted to a matrix and received an increment of an adhesive luting cement. The specimens were subjected to the shear bond strength test. ANOVA and Tukey's tests showed that G3 (8.53 MPa) and G4 (8.63 MPa) differed significantly (p=0.001) from G1 (13.34 MPa). The highest mean shear bond strength values were found in G5 (14.78 MPa) and G6 (15.86 MPa). Air-abrasion of CR surface associated with an adhesive system provided an effective bond of the CR to the adhesive luting cement, regardless the pre-treatment with the phosphoric acid.

Effect of seating forces on cement-ceramic adhesion in microtensile bond tests

Objectives: The aim of this study was to evaluate the effect of different seating forces during cementation in cement-ceramic microtensile bond strength (μTBS). Materials and methods: Forty-five blocks (5 × 5 × 4 mm3) of a glass-infiltrated alumina-based ceramic (In-Ceram Alumina) were fabricated according to the manufacturer's instructions and duplicated in resin composite. Ceramic surfaces were polished, cleaned for 10 min in an ultrasonic bath, silica coated using a laboratory type of air abrasion device, and silanized. Each treated ceramic block was then randomly assigned to five groups (n = 9) and cemented to a composite block under five seating forces (10 g, 50 g, 100 g, 500 g, and 750 g) using a dual-cured resin cement (Panavia F). The ceramic-cement-composite assemblies were cut under coolant water to obtain bar specimens (1 mm × 0. 8 mm2). The μTBS tests were performed in a universal testing machine (1 mm/min). The mean bond strengths values were statistically analyzed using one-way ANOVA (α ≤ 0. 05). Results: Different seating forces resulted in no significant difference in the μTBS results ranging between 13. 1 ± 4. 7 and 18. 8 ± 2. 1 MPa (p = 0. 13) and no significant differences among cement thickness. Conclusions: Excessive seating forces during cementation seem not to affect the μTBS results. Clinical relevance: Excessive forces during the seating of single all-ceramic restorations cementation seem to display the same tensile bond strength to the resin cement. © 2012 Springer-Verlag.

Effect of immersion cleansers on the bond strength between a denture base resin and acrylic resin teeth

The aim of the present study was to assess the shear bond strength between a heat-polymerized denture base resin and acrylic resin teeth after immersion in different denture cleansers by simulating a 180-day use. Two acrylic teeth (Biotone, Biotone IPN, Dentsply Ind. e Com., Rio de Janeiro, RJ, Brazil) were chosen for bonding to a heat-polymerized denture base resin (Lucitone 550- Dentsply Ind. e Com., Rio de Janeiro, RJ, Brazil). Eighty specimens were produced and divided into eight groups (n=10) according to their experimental condition (distilled water, 2% chlorhexidine digluconate, 1% sodium hypochlorite and Corega Tabs). Shear bond strength tests (MPa) were performed with a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed by two-way analysis of variance (ANOVA) and Student-Newman-Keuls' multiple comparisons post hoc analysis (α=.05). The shear bond strength results revealed statistically significant differences between the groups. For the Biotone IPN tooth, significantly lower shear bond strength values were found for the group immersed in sodium-perborate solution (4.48±2.18 MPa) than for the group immersed in distilled water (control group) (10.83±1.84 MPa). For Biotone, significantly higher bond strength values (10.04±3.28 MPa) were found for the group immersed in Corega Tabs than for the control group (5.45±2.93 MPa). The immersion in denture cleanser solutions was more detrimental to the conventional acrylic denture tooth (Biotone) than to the highly cross-linked denture tooth (Biotone IPN). However, this effect was not observed for the groups immersed in Corega Tabs solution, regardless of the type of denture tooth. © 2013 Elsevier Ltd.

Estudo da resistência às forças de cisalhamento de três sistemas condicionantes indicados para a colagem de acessórios ortodônticos

Pós-graduação em Odontologia - FOA

Resistência ao microcisalhamento de diferentes sistemas adesivos no esmalte dental humano

Pós-graduação em Odontologia Restauradora - ICT

Análise da resistência adesiva à dentina de diferentes sistemas adesivos pelo teste de microtração e microscopia eletrônica de varredura

Pós-graduação em Ciências Odontológicas - FOAR

Efficacy of Surface Treatments on the Bond Strength of Resin Cements to Two Brands of Zirconia Ceramic

Purpose: To compare the shear bond strength (SBS) of two cements to two Y-TZP ceramics subjected to different surface treatments.Materials and Methods: Zirconia specimens were made from Lava (n = 36) and IPS e.max ZirCAD (n = 36), and their surfaces were treated as follows: no treatment (control), silica coating with 30-mu m silica-modified alumina (Al2O3) particles (CoJet Sand), or coating with liners Lava Ceram for Lava and Intensive ZirLiner for IPS e.max ZirCAD. Composite resin cylinders were bonded to zirconia with Panavia F or RelyX Unicem resin cements. All specimens were thermocycled (6000 cycles at 5 degrees C/55 degrees C) and subjected to SBS testing. Data were analyzed by post-hoc test Tamhane T2 and Scheffe tests (alpha = 0.05). Failure mode was analyzed by stereomicroscope and SEM.Results: With both zirconia brands, CoJet Sand showed significantly higher SBS values than control groups only when used with RelyX Unicem (p = 0.0001). Surface treatment with liners gave higher SBS than control groups with both ceramic brands and cements (p < 0.001). With both zirconia brands, the highest SBS values were obtained with the CoJet and RelyX Unicem combination (> 13.47 MPa). Panavia F cement showed significantly better results when coupled with liner surface treatment rather than with CoJet (p = 0.0001, SBS > 12.23 MPa). In untreated controls, Panavia F showed higher bond strength than RelyX Unicem; the difference was significant (p = 0.016) in IPS e.max ZirCAD. The nontreated specimens and those treated with CoJet Sand exhibited a high percentage of adhesive and mixed A (primarily adhesive) failures, while the specimens treated with liners presented an increase in mixed A and mixed C (primarily cohesive) failures as well as some cohesive failure in the bulk of Lava Ceram for both cements.Conclusion: CoJet Sand and liner application effectively improved the SBS between zirconia and luting cements. This study suggests that different interactions between surface treatments and luting cements yield different SBS: in clinical practice, these interactions should be considered when combining luting cements with surface treatments in order to obtain the maximum bond strength to zirconia restorations.

Bond strength of composite to dentin: effect of acid etching and laser irradiation through an uncured self-etch adhesive system

This study evaluated the effect on micro-tensile bond strength (mu-TBS) of laser irradiation of etched/unetched dentin through an uncured self-etching adhesive. Dentinal surfaces were treated with Clearfil SE Bond Adhesive (CSE) either according to the manufacturer's instructions (CSE) or without applying the primer (CSE/NP). The dentin was irradiated through the uncured adhesive, using an Nd: YAG laser at 0.75 or 1 W power settings. The adhesive was cured, composite crowns were built up, and the teeth were sectioned into beams (0.49 mm(2)) to be stressed under tension. Data were analyzed using one-way ANOVA and Tukey statistics (alpha = 5%). Dentin of the fractured specimens and the interfaces of untested beams were observed under scanning electron microscopy (SEM). The results showed that non-etched irradiated surfaces presented higher mu-TBS than etched and irradiated surfaces (p < 0.05). Laser irradiation alone did not lead to differences in mu-TBS (p > 0.05). SEM showed solidification globules on the surfaces of the specimens. The interfaces were similar on irradiated and non-irradiated surfaces. Laser irradiation of dentin through the uncured adhesive did not lead to higher mu-TBS when compared to the suggested manufacturer's technique. However, this treatment brought benefits when performed on unetched dentin, since bond strengths were higher when compared to etched dentin.

Effect of Surface Conditioning Modalities on the Repair Bond Strength of Resin Composite to the Zirconia Core / Veneering Ceramic Complex

Purpose: This study evaluated the effect of different surface conditioning protocols on the repair strength of resin composite to the zirconia core / veneering ceramic complex, simulating the clinical chipping phenomenon.Materials and Methods: Forty disk-shaped zirconia core (Lava Zirconia, 3M ESPE) (diameter: 3 mm) specimens were veneered circumferentially with a feldspathic veneering ceramic (VM7, Vita Zahnfabrik) (thickness: 2 mm) using a split metal mold. They were then embedded in autopolymerizing acrylic with the bonding surfaces exposed. Specimens were randomly assigned to one of the following surface conditioning protocols (n = 10 per group): group 1, veneer: 4% hydrofluoric acid (HF) (Porcelain Etch) + core: aluminum trioxide (50-mu m Al2O3) + core + veneer: silane (ESPE-Sil); group 2: core: Al2O3 (50 mu m) + veneer: HF + core + veneer: silane; group 3: veneer: HF + core: 30 mu m aluminum trioxide particles coated with silica (30 mu m SiO2) + core + veneer: silane; group 4: core: 30 mu m SiO2 + veneer: HF + core + veneer: silane. Core and veneer ceramic were conditioned individually but no attempt was made to avoid cross contamination of conditioning, simulating the clinical intraoral repair situation. Adhesive resin (VisioBond) was applied to both the core and the veneer ceramic, and resin composite (Quadrant Posterior) was bonded onto both substrates using polyethylene molds and photopolymerized. After thermocycling (6000 cycles, 5 degrees C-55 degrees C), the specimens were subjected to shear bond testing using a universal testing machine (1 mm/min). Failure modes were identified using an optical microscope, and scanning electron microscope images were obtained. Bond strength data (MPa) were analyzed statistically using the non-parametric Kruskal-Wallis test followed by the Wilcoxon rank-sum test and the Bonferroni Holm correction (alpha = 0.05).Results: Group 3 demonstrated significantly higher values (MPa) (8.6 +/- 2.7) than those of the other groups (3.2 +/- 3.1, 3.2 +/- 3, and 3.1 +/- 3.5 for groups 1, 2, and 4, respectively) (p < 0.001). All groups showed exclusively adhesive failure between the repair resin and the core zirconia. The incidence of cohesive failure in the ceramic was highest in group 3 (8 out of 10) compared to the other groups (0/10, 2/10, and 2/10, in groups 1, 2, and 4, respectively). SEM images showed that air abrasion on the zirconia core only also impinged on the veneering ceramic where the etching pattern was affected.Conclusion: Etching the veneer ceramic with HF gel and silica coating of the zirconia core followed by silanization of both substrates could be advised for the repair of the zirconia core / veneering ceramic complex.

Zirconia-Porcelain Bonding: Effect of Multiple Firings on Microtensile Bond Strength

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)