648 resultados para Endodontic cements
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The aim of the current study was to evaluate the presence of debris and smear layer after endodontic irrigation with different formulations of 2% chlorhexidine gluconate (CHX) and its effects on the push-out bond strength of an epoxy-based sealer on the radicular dentin. One hundred extracted human canines were prepared to F5 instrument and irrigated with 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. Fifty teeth were divided into five groups (n=10), according to the final irrigation protocol with different 2% CHX formulations: G1 (control, no final rinse irrigation), G2 (CHX solution), G3 (CHX gel), G4 (Concepsis), and G5 (CHX Plus). In sequence, the specimens were submitted to scanning electron microscopy (SEM) analysis, in the cervical-medium and medium-apical segments, to evaluate the presence of debris and smear layer. The other 50 teeth were treated equally to a SEM study, but with the root canals filled with an epoxy-based endodontic sealer and submitted to a push-out bond strength test, in the cervical, middle, and apical thirds. G2, G3, G4, and G5 provided higher precipitation of the debris and smear layer than G1 (P<0.05), but these groups were similar to each other (P>0.05), in both segments. The values obtained in the push out test did not differ between groups, independent of the radicular third (P>0.05). The CHXs formulations caused precipitation of the debris and smear layer on the radicular dentin, but these residues did not interfere in the push-out bond strength of the epoxy-based sealer. Microsc. Res. Tech. 77:17-22, 2014. (c) 2013 Wiley Periodicals, Inc.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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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.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Reabilitação Oral - FOAR
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Pós-graduação em Odontologia Restauradora - ICT
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Pós-graduação em Odontologia Restauradora - ICT
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Pós-graduação em Odontologia Restauradora - ICT
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Pós-graduação em Odontologia Restauradora - ICT
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Pós-graduação em Odontologia Restauradora - ICT
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Pós-graduação em Odontologia Restauradora - ICT
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The purpose of this study was to evaluate in vitro the shear bond strenght to bovine dentin, during 24h and 30 days with the following variables: resin cements Enforce and Panavia F; aesthetics restorative materials Art Glass, IPS Empress 2 and Targis, with surface treatment with microetching with aluminium oxide, fluoridric acid and silane. Two hundred eighty eight sound bovine teeth from 3 years old animals constituted the samples after inclusion on polyester resin box. lnstron model 430 Universal Testing Machine, a crosshead speed 0,5 mm/min and load cells of 500 Kg, was used for shear bond strenght testing (MPa). The results were statistically analysed by ANOVA The best result was obtained with /PS Empress 2, microetched with aluminium oxide, fluoridric acid and silane, cemented with Panavia F and stored in distilled water, 3f'C during 30 days
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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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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)