Adhesive Vs no-adhesive FRC-post cementation: pull-out bond strength evaluation

Objectives: to evaluate the effect of different strategies for post cementation on the pull-out bond strength of a DT glass-FRC post. Methods: Root canals of 70 single-rooted bovine teeth (16mm-length) were prepared to 9mm using a preparation drill of a double-tapered glass-FRC post system (White Post DC #2, FGM). Each root was embedded in a PVC using acrylic resin up to 3mm of the most coronal portion of the specimen. The specimens were allocated into seven groups (n=10) based on the strategies for cementation: Gr1- ScotchBond Multi Purpose plus (SBMP)+Relyx ARC resin cement; Gr2- Single Bond + Relyx ARC; Gr3- ED-Primer+Panavia F resin cement; Gr4- SBMP+AllCem resin cement; Gr5- Relyx ARC; Gr6- Relyx Unicem resin cement; Gr7- Relyx Luting 2 glass ionomer resin cement. After cementation, the specimens were stored for 7 days (humid environment at 37°C) and each one submitted to pull-out bond strength testing (the specimen' inferior part was firstly fixed and then the fiber post was grasped and pulled-out). The data (Kgf) were submitted to the statistic analysis (1-way ANOVA and Tukey tests, a=.05). The tested specimens were analyzed under optical microscope and SEM for fracture analyzing. Results: The strategy for post cementation did affect the pull-out bond strength results (P<0.0001) significantly. The results of Gr6, Gr1 and Gr4 were the highest. Gr2, Gr3 and Gr7 were the lowest. Gr5 was similar to Gr4 and inferior to Gr6 and Gr1. Conclusion: The strategy of post cementation may influence the retention of post. The etch and rinse three-step adhesive system appears be a good way, but application of other adhesive system (etch and rinse simplified-, and self etch-adhesive systems) did not warranty high retention strength values. The simplified self-adhesive resin cements (without adhesive application) may be a good possibility. Further studies must be conducted.