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.

Can Heat Treatment Procedures of Pre-hydrolyzed Silane Replace Hydrofluoric Acid in the Adhesion of Resin Cement to Feldspathic Ceramic?

Purpose: To evaluate the influence of heat treatment (HT) procedures of a pre-hydrolyzed silane on bond strength of resin cement to a feldspathic ceramic.Materials and Methods: Ceramic and composite blocks (N = 30) were divided into six groups (n = 5) and subjected to the following conditioning procedures: G1: 9.6% hydrofluoric acid (HF) for 20 s + silane (RelyX Ceramic Primer, 3M ESPE) + resin cement (Panavia F2.0, Kuraray) (control); G2: HF (20 s) + silane + heat treatment in furnace (HTF) (100 degrees C, 2 min) + resin cement; G3: silane + HTF + resin cement; G4-HF (20 s) + silane + heat treatment with hot air (HTA) (50 +/- 5 degrees C for 1 min) + resin cement; G5: silane + HTA + resin cement; G6: silane + resin cement. The microtensile bond strength (MTBS) test was performed using a universal testing machine (1 mm/min). After debonding, the substrate and adherent surfaces were analyzed using a stereomicroscope and SEM to categorize the failure types. The data were statistically evaluated using one-way ANOVA and Tukey's test (5%).Results: The control group (G1) showed no pre-test failures and presented significantly higher mean MTBS (16.01 +/- 1.12 MPa) than did other groups (2.63 +/- 1.05 to 12.55 +/- 1.52 MPa) (p = 0.0001). In the groups where HF was not used, HTF (G3: 12.55 +/- 1.52 MPa) showed significantly higher MTBS than did HTA (G5: 2.63 +/- 1.05 MPa) (p < 0.05). All failure types were mixed, ie, adhesive between the resin cement and ceramic accompanied by cohesive failure in the cement.Conclusion: Heat treatment procedures for the pre-hydrolyzed silane either in a furnace or with the application of hot air cannot replace the use of HF gel for the adhesion of resin cement to feldspathic ceramic. Yet when mean bond strengths and incidence of pre-test failures are considered, furnace heat treatment delivered the second best results after the control group, being considerably better than hot air application.

Effect of reducing acid etching time on bond strength to noncarious and caries-affected primary and permanent dentin

The purpose was to evaluate the effect of acid etching time on the bond strength of a simplified etch-and-rinse adhesive system to noncarious and caries-affected dentin of primary and permanent teeth. Methods: Twenty-four extracted primary and permanent teeth were divided into three groups, according to the acid etching time. Four teeth from each group were exposed to a microbiological caries-inducing protocol. After caries removal, noncarious and caries-affected dentin surfaces were etched with 37 percent phosphoric acid for five, 10, or 15 seconds prior to the application of Prime & Bond NT adhesive. Crowns were restored with resin composite and prepared for microtensile testing. Data were submitted to Kruskal-Wallis and Mann-Whitney tests (á=0.05). Results: Higher bond strengths were obtained for noncarious dentin vs. cariesaffected dentin for both primary and permanent teeth. Reducing the acid etching time from 15 to five seconds did not affect the bond strength to caries-affected or noncarious dentin in primary teeth. For permanent teeth, lower bond strength values were observed when the noncarious dentin was etched for five seconds, while no difference was seen between 10 and 15 seconds. Conclusions: For Prime & Bond NT, the etching of dentin for five seconds could be recommended for primary teeth, while 10 seconds would be the minimum time for permanent teeth.

Durability of Microtensile Bond to Nonetched and Etched Feldspar Ceramic: Self-adhesive Resin Cements vs Conventional Resin

Purpose: The objective of this study was to evaluate the effect of thermocycling (TC), self-adhesive resin cements and surface conditioning on the microtensile bond strength (mu TBS) between feldspathic ceramic blocks and resin cements.Materials and Methods: Fifty-six feldspathic ceramic blocks (10 x 7 x 5 mm) (Vita Mark II) were divided into groups according to the factors "resin cement" (3 cements) and "surface conditioning" (no conditioning or conditioning [10% hydrofluoric acid etching for 5 min + silanization]) (n = 8): group 1: conditioning+Variolink II (control group); group 2: no conditioning+Biscem; group 3: no conditioning+RelyX U100; group 4: no conditioning+Maxcem Elite; group 5: conditioning+Biscem; group 6: conditioning+RelyX U100; group 7: conditioning+Maxcem Elite. The ceramic-cement blocks were sectioned to produce non-trimmed bar specimens (adhered cross-sectional area: 1 +/- 0.1 mm(2)), which were divided into two storage conditions: dry, mu TBS immediately after cutting; TC (12,000x, 5 degrees C/55 degrees C). Statistical significance was deterimined using two-way ANOVA (7 strategies and 2 storage conditions) and the post-hoc Tukey test (p<0.05).Results: Resin cement and thermocycling affected the mu TBS significantly (p = 0.001). In the dry condition, group 5 (18 +/- 6.5 MPa) presented the lowest values of mu TBS when compared to the other groups. TC decreased the mean mu TBS values significantly (p<0.05) for all resin cements tested (9.7 +/- 2.3 to 22.1 +/- 6.3 MPa), except for the resin cement RelyX U100 (22.1 +/- 6.3 MPa). In groups 3 and 4, it was not possible to measure mu TBS, since these groups had 100% pre-test failures during sectioning. Moreover, the same occurred in group 2 after TC, where 100% failure was observed during thermocycling (spontaneous failures).Conclusion: Hydrofluoric acid etching and silanization of the feldspathic ceramic surface are essential for bonding self-adhesive resin cement to a feldspathic ceramic, regardless of the resin cement used. Non-etched ceramic is not recommended.

The influence of internal surface treatments on tensile bond strength for two ceramic systems

Statement of the Problem: the ceramic composition and surface microstructure of all-ceramic restorations are important components of an effective bonding substrate. Hydrofluoric acid and sandblasting are well-known procedures for surface treatment; however, surface treatment for high alumina-containing and lithium disilicate ceramics have not been fully investigated.Purpose: This in vitro study evaluated the tensile bond strength of resin cement to two types of ceramic systems with different surface treatments.Methods and Materials: Thirty specimens of each ceramic system were made according to the manufacturer's instructions and embedded in polyester resin. Specimens of In-Ceram Alumina [1] and IPS Empress 2 [E] were distributed to three groups with differing surface treatments (n=10): sandblasting with 50 jam aluminum oxide (APA); sandblasting with 110 pm aluminum oxide modified with silica particles (ROCATEC System-RS); a combination of sandblasting with APA and 10% hydrofluoric acid etching (HA) for two minutes on In-Ceram and for 20 seconds for IPS Empress 2. After the respective surface treatments, all the specimens were silanated, and Rely-X resin cement was injected onto the ceramic surface and light polymerized. The specimens were stored in distilled water at 37 degrees C for 24 hours and thermally cycled 1,100 times (5 degrees C/55 degrees C). The tensile bond strength test was performed in a universal testing machine at a 0.5 mm/minute crosshead speed.Results: the mean bond strength values (AWa) for IPS Empress 2 were 12.01 +/- 5.93 (EAPA), 10.34 +/- 1.77 (ERS) and 14.49 +/- 3.04 (EHA). The mean bond strength values for In-Ceram Alumina were 9.87 +/- 2.40 JAPA) and 20.40 +/- 6.27 (IRS). All In-Ceram specimens treated with 10% hydrofluoric acid failed during thermal cycling.Conclusion: the Rocatec system was the most effective surface treatment for In-Ceram Alumina ceramics; whereas, the combination of aluminum oxide sandblasting and hydrofluoric acid etching for 20 seconds worked more effectively for Empress 2 ceramics.

Influence of ceramic surface conditioning and resin cements on microtensile bond strength to a glass ceramic

Statement of problem. It is not clear how different glass ceramic surface pretreatments influence the bonding capacity of various luting agents to these surfaces.Purpose. The purpose of this study was to evaluate the microtensile bond strength (mu TBS) of 3 resin cements to a lithia disilicate-based ceramic submitted to 2 surface conditioning treatments.Material and methods. Eighteen 5 X 6 X 8-mm ceramic (IPS Empress 2) blocks were fabricated according to manufacturer's instructions and duplicated in composite resin (Tetric Ceram). Ceramic blocks were polished and divided into 2 groups (n=9/treatment): no conditioning (no-conditioning/control), or 5% hydrofluoric acid etching for 20 seconds and silanization for 1 minute (HF + SIL). Ceramic blocks were cemented to the composite resin blocks with I self-adhesive universal resin cement (RelyX Unicem) or 1 of 2 resin-based luting agents (Multilink or Panavia F), according to the manufacturer's instructions. The composite resin-ceramic blocks were stored in humidity at 37 degrees C for 7 days and serially sectioned to produce 25 beam specimens per group with a 1.0-mm(2) cross-sectional area. Specimens were thermal cycled (5000 cycles, 5 degrees C-55 degrees C) and tested in tension at 1 mm/min. Microtensile bond strength data (MPa) were analyzed by 2-way analysis of variance and Tukey multiple comparisons tests (alpha=.05). Fractured specimens were examined with a stereomicroscope (X40) and classified as adhesive, mixed, or cohesive.Results. The surface conditioning factor was significant (HF+SIL > no-conditioning) (P<.0001). Considering the unconditioned groups, the mu TBS of RelyX Unicem was significantly higher (9.6 +/- 1.9) than that of Multilink (6.2 +/- 1.2) and Panavia F (7.4 +/- 1.9). Previous etching and silanization yielded statistically higher mu TBS values for RelyX Unicem (18.8 +/- 3.5) and Multilink (17.4 +/- 3.0) when compared to Panavia F (15.7 +/- 3.8). Spontaneous debonding after thermal cycling was detected when luting agents were applied to untreated ceramic surfaces.Conclusion. Etching and silanization treatments appear to be crucial for resin bonding to a lithia disilicate-based ceramic, regardless of the resin cement used.

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.

Effect of ceramic surface treatment on the shear bond strength of a resin cement to different ceramic systems

This study evaluated three surface treatments and their effects on the shear bond strength between a resin cement and one of three ceramics. The ceramic surfaces were evaluated with scanning electron microscopy (SEM ) as well. Specimens were treated with 50 μm aluminum oxide airborne particles, 10% hydrofluoric acid etching, or a combination of the two. Using a matrix with a center hole (5.0 mm × 3.0 mm), the ceramic bonding areas were filled with resin cement following treatment. The specimens were submitted to thermal cycling (1,000 cycles) and the shear bond strength was tested (0.5 mm/minute). The failure mode and the effect of surface treatment were analyzed under SEM . Data were submitted to ANOVA and a Tukey test (α = 0.05). Duceram Plus and IPS Empress 2 composite specimens produced similar shear bond strength results (p > 0.05), regardless of the treatment method used. Hydrofluoric acid decreased the shear bond strength of In-Ceram Alumina specimens. For all materials, surface treatments changed the morphological surface. All treatments influenced the shear bond strength and failure mode of the ceramic/resin cement composites.

Avaliação de tratamentos de superfície em diferentes sistemas cerâmicos e seu efeito na resistência de união a um cimento resinoso

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito de tratamento de superfície na composição de zircônia e na resistência de união com diferentes cimentos

Pós-graduação em Reabilitação Oral - FOAR

Efeito da neutralização do ácido fluorídrico, limpeza sônica dos precipitados e da cimentação sobre a resistência à flexão de uma cerâmica vítrea

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of Resin Bond Strength to Yttria-stabilized Tetragonal Zirconia and Framework Marginal Fit: Comparison of Different Surface Conditionings

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

Bonding of Y-TZP to Dentin: Effects of Y-TZP Surface Conditioning, Resin Cement Type, and Aging

Purpose: To evaluate the effects of two surface treatments, aging, and two resin cements on shear bond strength between dentin and yttrium-stabilized tetragonal zirconia polycrystal ceramic (Y-TZP).Materials and Methods: Eighty human molars were embedded in acrylic resin and sectioned 3 mm below the occlusal plane. These teeth and 80 cylindrical Y-TZP specimens (height, 4 mm; diameter, 3.4 mm) were divided into eight groups (n=10) using the following factors: Y-TZP surface treatment (Vi: low-fusing porcelain [vitrification] + hydrofluoric acid etching + silanization or Si: tribochemical silicatization); cementation strategies (PF: Pan avia or CC: Clearfil); and storage (nonaging or aging). Bonding surfaces of 40 Y-TZP specimens received Vi treatment, and the rest received Si treatment. Half of the ceramic-tooth assemblies were cemented with Panavia, the rest with Clearfil. Shear tests were executed using 0.4-mm-thick wire at 0.5 mm/min. Data were analyzed by three-way analysis of variance and Tukey test (alpha=0.05). Fractures were analyzed.Results: Y-TZP surface treatments did not affect bond strength (p=0.762, Vi = Si), while resin cements (p<0.001, Panavia > Clearfil) and aging (p=0.006, nonaging > aging) showed a significant effect. Most failures were in adhesive at dentin-cement interfaces; no failure occurred between zirconia and cement.Conclusion: When Y-TZP ceramic is bonded to dentin, the weakest interface is that between dentin and resin cement. The resin cement/Y-TZP interface was less susceptible to failures, owing to Y-TZP surface treatments.

Effect of Acid Neutralization and Mechanical Cycling on the Microtensile Bond Strength of Glass-ceramic Inlays

Objectives: To evaluate the hypothesis that a process of hydrofluoric acid precipitate neutralization and fatigue load cycling performed on human premolars restored with ceramic inlays had an influence on microtensile bond strength results (MTBS). Methods: MOD inlay preparations were performed in 40 premolars (with their roots embedded in acrylic resin). Forty ceramic restorations were prepared using glass-ceramic (IPS Empress). The inner surfaces of all the restorations were etched with 10% hydrofluoric acid for 60 seconds, rinsed with water and dried. The specimens were divided into two groups (N=20): 1-without neutralization; 2-with neutralization. All the restorations were silanized and adhesively cemented (self-curing and self-etching luting composite system, Multilink). Ten premolars from each group were submitted to mechanical cycling (1,400,000 cycles, 50N, 37 degrees C). After cycling, the samples were sectioned to produce non-trimmed beam specimens (vestibular dentin-restoration-lingual dentin set), which were submitted to microtensile testing. Results: Bond strength was significantly affected by the surface treatment (p<0.0001) (no neutralization > neutralization) and mechanical cycling (p<0.0001) (control > cycling) (2-way ANOVA and Tukey test, alpha=.05). Conclusion: Hydrofluoric acid precipitate neutralization appears to significantly damage the resin bond to glass-ceramic and should not be recommended. The clinical simulation of the specimens, by using mechanical cycling, is important when evaluating the ceramic-dentin bond.

Microtensile bond strength of a resin cement to feldpathic ceramic after different etching and silanization regimens in dry and aged conditions

Objectives. This study evaluated the durability of bond strength between resin cement and a feldspathic ceramic submitted to different etching regimens with and without silane coupling agent application.Methods. Thirty-two blocks (6.4 mm x 6.4 mm x 4.8 mm) were fabricated using a microparticulate feldspathic ceramic (Vita VM7), ultrasonically cleaned with water for 5 min and randomly divided into four groups, according to the type of etching agent and silanization method: method 1, etching with 10% hydrofluoric (HF) acid gel for I min + silanization; method 2, HF only; method 3, etching with 1.23% acidulated phosphate fluoride (APF) for 5 min + silanization; method 4, APF only. Conditioned blocks were positioned in their individual silicone molds and resin cement (Panavia F) was applied on the treated surfaces. Specimens were stored in distilled water (37 degrees C) for 24 h prior to sectioning. After sectioning the ceramic-cement blocks in x- and Y-axis with a bonded area of approximately 0.6 mm(2), the microsticks of each block were randomly divided into two storage conditions: Dry, immediate testing; TC, thermal cycling (12,000 times) + water storage for 150 d, yielding to eight experimental groups. Microtensile bond strength tests were performed in universal testing machine (cross-head speed: 1 mm/min) and failure types were noted. Data obtained (MPa) were analyzed with three-way ANOVA and Tukey's test (alpha = 0.05).Results. Significant influence of the use of silane (p < 0.0001), storage conditions (p = 0.0013) and surface treatment were observed (p = 0.0014). The highest bond strengths were achieved in both dry and thermocycled conditions when the ceramics were etched with HF acid gel and silanized (17.4 +/- 5.8 and 17.4 +/- 4.8 MPa, respectively). Silanization after HF acid gel and APT treatment increased the results dramatically (14.5 +/- 4.2-17.4 +/- 4.8 MPa) compared to non-silanized groups (2.6 +/- 0.8-8.9 +/- 3.1 MPa) where the failure type was exclusively (100%) adhesive between the cement and the ceramic.Significance. Silanization of the feldspathic ceramic surface after APF or HF acid etching increased the microtensile bond strength results significantly, with the latter providing higher results. Long-term thermocycling and water storage did not decrease the results in silanized groups. (C) 2006 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.