Influência do sistema de cimentação e do modo de ativação na resistência ao push-out de pinos de fibra de vidro

• Autor(a) principal: Ferreira, Reinaldo de Souza
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/14105
• topic: Fiber posts; Cementation; Resin cements; Self-adhesive resin cements; Dentin-bonding agents; Bond strength; Pinos de fibra; Cimentação; Cimentos de resina; Cimentos resinosos autoadesivos; Adesivos dentinários; Resistência de união; Pinos dentários; CNPQ::CIENCIAS DA SAUDE::ODONTOLOGIA

The aim of this study was to evaluate the influence of adhesive cementation system approach (total-etch or self-adhesive), activation mode (self-cure or dual-cure), canal third (cervical, middle or apical) and cement thickness on push-out bond strength of glass fiber post bonded on human roots. Forty roots were embebed in epoxy resin and endodontically treated (filled with guta percha and non-eugenol endodontic sealer). Following 7 days, the post spaces were prepared with low-speed post drills provided by the manufacturer (WhitePost DC #2, FGM) at a depth of 10 mm and the roots were randomly divided in 4 groups, according to cementation system and activations mode: (G1) RelyX ARC/Adper Scotchbond Multi-Purpose Plus (total-etch), dual-cure (G2) RelyX ARC/Adper Scotchbond Multi-Purpose Plus, self-cure, (G3) RelyX U100 (self-adhesive), dual-cure and (G4) RelyX U100, self-cure. After 7 days, each root was sectioned with water-cooled diamond blade, generating six 1-mm thickness slices (n=60). Before push-out bond strength test, digital images of both sides of the slices were captured with digital camera, in order to measure the post radius and the cement thickness. After mechanical test, new images were captured to evaluate the failure mode. A macro was developed in KS 400 software to speed and standardize the evaluation of cement thickness. Results were analyzed using three-way ANOVA (push-out) and Kruskall-Wallis test (cement thickness). Post-hoc multiple comparisons were performed using the Student-Newman-Keuls test. The correlation between resin cement thickness and bond strength was evaluated with regression analysis, linear model. All tests were performed with significance level set at 0.05. Push-out bond strength was significantly influenced by cement type (p= 0.0402): the RelyX U100 cement presented higher mean value. The dual-activated mode increased the bond strength in comparison to self-activated mode (p < 0.0001). Statically differences were observed between groups: G1 (22.4 ± 4.0 MPa) > G3 (20.4 ± 3.6 MPa) > G4 (17.8 ± 5.2 MPa) > G2 (13.5 ± 4.3 MPa). Bond strength was not affected by post space depth (p = 0,4749). The resin cement thicknesses were significantly different in root thirds: cervical (102 ± 45 µm) > middle (75 ± 29 µm) > apical (52 ± 28µm). No strong correlation between cement thickness and push-out bond strength was observed (r = - 0.2016, p = 0.0033). The main failure mode was mixed, except for G2 (74% adhesive failures at post-cement interface). It was concluded tha the self-adhesive cement showed a better performance than the conventional one, and both dual resin systems, specially the RelyX ARC, presented photo-activation dependence to attain greater adhesive bond strength.