Effect of thermal cycling on the bond strength of self-adhesive cements to fiber posts.

The aim of this study was to assess the push-out bond strengths of self-adhesive resin cements to epoxy resin-based fiber posts after challenging by thermocycling. Thirty-six single-rooted premolars were endodontically treated, and the post-spaces were drilled to receive RelyX Fiber posts #1. Three self-adhesive resin cements (RelyX Unicem, G-Cem, and Breeze) were used for luting fiber posts. The bonded specimens were either stored for 1 month in a moist field (37°C) or submitted to thermocycling (5,000 times) prior to push-out test. The maximum force required to dislodge the post via an apical-coronal direction was recorded (megapascal). The data were statistically analyzed with two-way ANOVA and Tukey tests (p < 0.05). The factors "luting cement" and "thermocycling" significantly influenced bond strengths. The initial push-out values of RelyX Unicem and Breeze were higher than those of G-Cem. After thermocycling, the bond strength of G-Cem increased and no differences were found between groups. RelyX Unicem and Breeze bond strengths were not affected by the thermal challenge. Thermal cycling and cement type differently influence the bond strengths of self-adhesive resin cements. Self-adhesive cements can represent an option for luting fiber posts into root canal.