254 resultados para Etch adhesives
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Odontologia Restauradora - ICT
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Pós-graduação em Ciências Odontológicas - FOAR
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Pós-graduação em Ciências Odontológicas - FOAR
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Pós-graduação em Reabilitação Oral - FOAR
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Pós-graduação em Química - IQ
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This study aimed to investigate physical performance of particleboards produced with waste from sawmills, containing different wood species, and two adhesives: urea-formaldehyde (UF) based resin and castor-oil (PU) based bi-component polyurethane resin. Panels were produced with nominal density 0.8gcm(-3); pressing temperature 110 degrees C; pressing time 10 min; specific pressure 5 MPa. Water absorption (2 and 24h); thickness swelling (2 and 24h); density; and moisture content were investigated. Results confirmed that the produced panels presented compatible physical properties in comparison with other researches referred in literature, proving the feasibility of inputs employed. Panels produced PU showed better performance than those produced with UF.
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This study evaluated the effect of intermediate adhesive resin application (IAR) on tensile bond strength (TBS) for early composite repairs in situations where substrate and repair composite bonded together were once of the same kind with the substrate (similar) and once other than the substrate material (dissimilar). Specimens from three types of composites (TPH Spectrum (TPH), Charisma (CHA) and Filtek Z250 (Z250)) were fabricated. The specimens in each composite group (n=72) were randomly divided into six subgroups (n=12). In each composite group, the similar and two dissimilar composites were bonded onto the substrates once using an IAR (Adper Single Bond Plus) and once without. After water storage for I week at 37 degrees C, substrate-adherent combinations were submitted to tensile test. Data were analyzed with three-way ANOVA and Tukey's tests (alpha=0.05). The substrate-adherent combination (p=0.0001), adherent (repair) composite (p=0.0001), and application of IAR (p=0.0001) significantly affected the results. Utilization of IAR improved the repair bond strength for all composite combinations. (C) 2013 Elsevier Ltd. All rights reserved.
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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.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Objective: The aim of this study was to evaluate the two-year clinical performance of Class III, IV, and V composite restorations using a two-step etch-and-rinse adhesive system (2-ERA) and three one-step self-etching adhesive systems (1-SEAs).Material and Methods: Two hundred Class III, IV, and V composite restorations were placed into 50 patients. Each patient received four composite restorations (Amaris, Voco), and these restorations were bonded with one of three 1-SEAs (Futurabond M, Voco; Clearfil S3 Bond, Kuraray; and Optibond All-in-One, Kerr) or one 2-ERA (Adper Single Bond 2/3M ESPE). The four adhesive systems were evaluated at baseline and after 24 months using the following criteria: restoration retention, marginal integrity, marginal discoloration, caries occurrence, postoperative sensitivity and preservation of tooth vitality. After two years, 162 restorations were evaluated in 41 patients. Data were analyzed using the chi(2) test (p<0.05).Results: There were no statistically significant differences between the 2-ERA and the 1-SEAs regarding the evaluated parameters (p>0.05).Conclusion: The 1-SEAs showed good clinical performance at the end of 24 months.
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Objective: The aim of this study was to evaluate the 5-year clinical performance of composite restorations of non-carious cervical lesions (NCCL) using a total-etch adhesive system with or without collagen removal with 10% sodium hypochlorite (NaOCl).Methods: In this study randomized controlled split-mouth clinical trial, one-hundred and thirty-eight NCCL were restored into 30 patients. Each patient received at least one pair of composite restorations (Filtek A110/3M ESPE), bonded either with 2 techniques: Conventional Technique - acid etching with 37% phosphoric acid + Prime & Bond NT (Denstply DeTrey); Deproteinization Technique - acid etching with 37% phosphoric acid + 10% NaOCl for 1 min + Prime & Bond NT. The two techniques were evaluated using the United States Public Health Service (USPHS) criteria at baseline, 18 months, 3 and 5 years. After five years, one-hundred and six restorations were evaluated in 24 patients. Data were analyzed using the Chi-Square test (p < 0.05).Results: There were no statistically significant differences between the two techniques regarding the evaluated parameters (p > 0.05).Conclusion: After 5 years, the application of 10% NaOCl deproteinization on etched dentine did not affect the clinical performance of composite restorations placed in NCCL when compared to the conventional total-etch technique.Clinical significance: Clinical studies evaluating the performance of the Deproteinization Technique are scarce. In this study, this technique showed similar clinical performance at the end of 5 years when compared to a conventional total-etch technique. (C) 2014 Elsevier Ltd. All rights reserved.
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Background. Reduced surface tension of liquids results in higher surface wetting ability and diffusivity by the substrate. Objectives. The objective of this study was to evaluate the influence of the Grander Technology in reducing the surface tension of adhesive systems. Methods. Two adhesive systems (self-etch and total-etch) were modified by physical contact with the Grander system Flexible unit to revitalize water, for 48 h. Surface tension of adhesive systems and water in normal and grander-modified conditions was measured with a goniometer. Results. The results showed a reduction of surface tension for all conditions grander-modified between 3-15%. Conclusions. Grander Technology was effective in reducing the surface tension of the Single Bond and Clearfil SE Bond adhesive systems. Clinical significance. Grander technology was employed to restructure the molecular structure of water-based adhesive systems, which can increase their wetness capacity and therefore ensure a greater diffusibility.