Objectives: The post-to-composite interface is still a weak link in fiber post bonding. This study evaluated the effects of chairside silanization and industrial conditioning of fiber posts on the adhesion to a composite core and luting material. Methods: Sixty pre-fabricated quartz fiber posts (DT Light Post, L) were either left untreated (control) or they were treated with a pre-activated silane solution (Monobond Plus) and a multi-component silane system (Clearfil SE Bond mixed with Clearfil Porcelain Bond Activator), respectively (n=20 per group). Twenty L posts had already been conditioned by an industrial silica/silane coating (DT Light SL). All the posts were surrounded by 2-mm thick disks of dual-cured composite (MultiCore Flow). After water storage (24 h, 37 degrees C), half of the specimens in each group were subsequently subjected to push-out testing (Zwicki 1120), while the other half were tested after thermocycling (1500 cycles, 5-55 degrees C). Data were statistically analyzed with two-way ANOVA. Tukey's test was applied for post-hoc comparisons at p<0.05. Results: Interfacial push-out bond strengths were significantly influenced by silanization (p<0.001), but not by thermocycling (p=0.118). Silanized fiber posts showed significantly higher bond strengths than the control posts, even after thermocycling (p<0.05). No significant differences were found between the three silane coupling strategies (p>0.05). Mean bond strength values in MPa (n=10, standard deviations in parentheses):
Coupling strategy | Before thermocycling | After thermocycling |
No silane (control) | 13.1 (0.8) | 11.3 (0.9) |
Single-component silane | 14.9 (0.6) | 15.3 (1.0) |
Multi-component silane | 16.1 (2.0) | 15.8 (1.5) |
Industrial coating | 15.3 (1.7) | 15.3 (0.9) |
Conclusions: Silanization of the fiber post surface had beneficial effects on the post-to-composite bond. Chairside silanization and industrial silica/silane coating seem to be equally effective.