Coupling of Composite Resin Cements to Quartz Fiber Posts: A Comparison of Industrial and "Chairside" Treatments of the Post Surface

Purpose: To evaluate the influence of surface treatments on microtensile bond strength of luting resin cements to fiber posts. Materials and Methods: Forty-two quartz fiber posts (Light Post, RTD) were divided into 7 groups (n = 6) according to the surface treatment. I and II: experimental patented industrial treatment consisting of zirconium oxide coating and silanization (RTD); III: industrial treatment followed by adhesive application (XPBond, Dentsply Caulk); IV: adhesive (XPBond); V: adhesive (Prime&Bond NT, Dentsply Caulk); VI: silane (Calibra Silane, Dentsply Caulk); VII: no treatment. Adhesives were used in the self-curing mode. Two cements (Sealbond, RTD - group I, and Calibra, Dentsply Caulk - groups II to VII) were applied on the posts to produce cylindrical specimens. Post/cement interfaces were evaluated under SEM. The surface of the industrially coated posts was examined using energy dispersive analysis by x-ray. Cylinders were cut to obtain microtensile sticks that were loaded in tension at a crosshead speed of 0.5 mm/min until failure. Statistical analysis was performed using Kruskal-Wallis analysis of variance followed by Dunn's multiple range test for post-hoc comparisons (p 0.05). Weibull analysis was also performed. Results: The post/cement bond strength was significantly higher on fiber posts treated industrially (I: 23.14 ± 8.05 MPa; II: 21.56 ± 7.07 MPa; III: 22.37 ± 7.00 MPa) or treated with XPBond adhesive (IV: 21.03 ± 5.34 MPa) when compared to Prime&Bond NT application (V: 14.05 ± 5.06 MPa), silanization (VI: 6.31 ± 4.60 MPa) or no treatment (VII: 4.62 ± 4.31) of conventional fiber posts (p 0.001). Conclusion: The experimental industrial surface treatment and the adhesive application enhanced fiber post to resin cement interfacial strength. Industrial pretreatment may simplify the clinical luting procedure. Keywords: fiber posts, resin cement, microtensile bond strength, surface treatment, zirconium oxide coating