title: Acid Etching and Surface Coating of Glass-Fiber Posts: Bond Strength and Interface Analysis.
abstract: The aim of this study was to evaluate the bond strength of a composite resin to glass-fiber post (GFP) treated or not with phosphoric acid, silane coupling agent, and unfilled resin. GFPs were etched or not with 37% phosphoric acid and different surface coating applied: silane coupling agent, unfilled resin, or both. Composite resin blocks were built around a 4-mm height on the GFP. Unfilled resin (20 s) and composite resin (40 s) were light activated by a light-emitting diode unit. The specimens were stored in distilled water at 37 °C for 24 h. Microtensile bond test was performed using a mechanical testing machine until failure (n=10). The data were analyzed using two-way ANOVA followed by Student-Newman-Keuls' test (p<0.05). Failure modes were classified as adhesive, mixed, or cohesive failures. Additional specimens (n=3) were made to analyze the bonded interfaces by scanning electron microscopy. The statistical analysis showed the factor 'surface coating' was significant (p<0.05), whereas the factor 'HP etching' (p=0.131) and interaction between the factors (p=0.171) were not significant. The highest bond strength was found for the silane and unfilled resin group (p<0.05). A predominance of adhesive and cohesive failures was found. Differences regarding the homogeneity and thickness of the unfilled resin layer formed by different GFP surface treatments were observed. The application of silane and unfilled resin can improve the bond strength between GFP and resin composite.
authors.affiliation: Department of Restorative Dentistry, Dental School, Universidade de Passo Fundo, Passo Fundo, RS, Brazil.
authors.forename: Doglas
authors.initials: D
authors.lastname: Cecchin
authors.affiliation: Department of Restorative Dentistry, Dental School, Universidade de Passo Fundo, Passo Fundo, RS, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Farina
authors.affiliation: Department of Prosthodontics, Dental School, Universidade de Taubaté, Taubaté, SP, Brazil.
authors.forename: Rafael Pino
authors.initials: RP
authors.lastname: Vitti
authors.affiliation: Department of Restorative Dentistry, Dental School, Universidade Federal de Pelotas, Pelotas, RS, Brazil.
authors.forename: Rafael Ratto
authors.initials: RR
authors.lastname: Moraes
authors.affiliation: Department of Prosthodontics, Dental School, Faculdade Meridional, Passo Fundo, RS, Brazil.
authors.forename: Ataís
authors.initials: A
authors.lastname: Bacchi
authors.affiliation: Department of Prosthodontics, Dental School, Faculdade Meridional, Passo Fundo, RS, Brazil.
authors.forename: Aloísio Oro
authors.initials: AO
authors.lastname: Spazzin
mesh_terms: D000134:Acid Etching, Dental; D006801:Humans; D008855:Microscopy, Electron, Scanning; D011176:Post and Core Technique; D013499:Surface Properties