Effect of Different Adhesive Systems and Resin Cements on the Push-Out Bond Strength of Fiber Reinforced Posts to Root Dentin

Abstract

Good bond strength between fiber-reinforced posts (FRPs) and root dentin is essential for successful rehabilitation of endodontically treated teeth. 45 human premolar teeth were divided into three main groups (n = 15) based on bonding agent use: no bonding (control), light-cured (LC), and dual-cured (DC). Each group was further split by cement type: self-adhesive resin cement, bioactive resin cement, and core build-up material, totaling nine subgroups. The teeth were sectioned perpendicularly to the root surface to obtain two middle-root slices. After thermocycling, the push-out bond strength (PBS) test was performed and data were statistically analyzed with the ANOVA test followed by the post hoc Tukey test. Failure modes were examined under a stereomicroscope and statistically evaluated using the χ² test. There was a significant difference in the PBS between test groups (p < 0.0001*). In control groups, core build-up material (Control/LZ = 7.6 ± 3.4 MPa) had significantly lower PBS than the rest of the groups, except Control/AB = 9.9 ± 3.3 MPa. The application of bonding agents significantly increased bond strength for bioactive cement (LC/AB = 14.8 ± 4.8 MPa and DC/AB = 17.7 ± 4.5 MPa) and core build-up material (LC/LZ = 20.4 ± 6.4 MPa and DC/LZ = 16.4 ± 3.8 MPa). Notably, self-adhesive resin cement achieved statistically similar PBS even without the application of bonding agent (Control/RX = 13.6 ± 3.1 MPa, LC/RX = 17.4 ± 5.5 MPa, and DC/RX = 17.0 ± 5.8 MPa). Self-adhesive resin cement can bond effectively to root dentin without additional bonding agents. However, bioactive and core build-up cements need bonding agents for optimal performance, highlighting the need to tailor bonding strategies to the specific cement used. Bonding FRPs to intra-radicular dentin was always a challenge. A strong bond to root dentin is an important factor to ensure the success and longevity of post and core restorations. This study provides great evidence for the significant influence of adhesive systems and resin cements on the bond strength of FRPs to root dentin. Using this study, clinicians will perform an informed choice of restorative materials for each clinical situation and select the best adhesive/cement combo to achieve good bond strength.