Adhesion between fiber posts and resin luting agents: a microtensile bond strength test and an SEM investigation following different treatments of the post surface

Purpose: (1) To evaluate the interfacial strength between FRC Postec posts and three luting agents (Multilink, Variolink 11, and MultiCore Flow) following different surface treatments, and (2) to observe the effect of sandblasting (Rocatec Pre) on the surface morphology of methacrylate-based fiber posts. Materials and Methods: The posts received one of the following surface treatments: (1) sandblasting, (2) sandblasting + silanization, (3) silanization or (4) no treatment. The three luting agents were bonded to the post and the post-cement bond strength was evaluated with the microtensile test. SEM observation of sandblasted and nontreated posts was performed. Post-cement interfaces were also evaluated. Data were statistically analyzed with two-Way ANOVA with post treatment and luting agent as factors. Tukey's test was applied for post-hoc comparisons. Results: Post treatment and the interaction between type of luting agent and type of post treatment were significant factors for bond strength (p < 0.001). The type of luting agent did not significantly influence bond strength (p = 0.07). Sandblasting + silanization performed better than sandblasting or no treatment (p < 0.001). Silanization resulted in significantly higher bond strengths than no treatment (p = 0.045). No differences were detected between sandblasting + silanization and silanization. SEM observation revealed an increased surface roughness and exposure of fibers in sandblasted posts. Conclusion: Silanization was confirmed to be a reliable method for improving the bond strength of resin luting agents to fiber posts. Bond strength of resin luting agents to fiber posts was not influenced by the type of luting agent. The sandblasting procedure modified the methacrylate-based post surface texture.