Does the Cementation System Affect Regional Bond Strength of Fiber-Post?

Objectives: To evaluate the influence of the cementation system on the regional push-out bond strength (BS) and failure pattern of fiber posts to radicular dentin. Methods: The roots of forty-eight extracted human maxillary central incisors were prepared and divided into three groups (n=16), according to the cementation systems: Adper Scotchbond Multi-Purpose + resin cement RelyX ARC (SBMP+ARC); Adper Single Bond 2 + RelyX ARC (SB+ARC) and RelyX U100 (U100). The fiber glass posts (Tenax Fiber Trans Esthetic Post System) were cemented in accordance with the manufacturer's instructions of each cementation system. After water storage at 37°C for one week, the roots were sectioned transversely into six 1-mm thick discs. Thus, two 1- mm thick disc were obtained from the cervical (TC), middle (TM) and apical (TA) thirds regions and the push-out test was carried out (0.5mm/min). The data were statistically analyzed by two-way repeated measures ANOVA and Tukey's tests (5%). Results: The cross-product interaction cementation system vs. root region was statistically significant (p<0.0001). When RelyX U100 was employed no significant difference was observed for the different root regions (p>0.05). On the other hand, statistically higher push-out bond strength values were detected in the TC for the groups SBMP+ARC and SB+ARC (p<0.05). The RelyX U100 showed more mixed failures than the SBMP+ARC in the apical third (p<0.05). Conclusion: The push-out bond strength of the self-adhesive cement RelyX U100 was not affected by the root region.