Evaluation of the Bond Strength and Fracture Resistance of Different Post Systems

To compare the bond strength and the fracture resistance of different post systems. Endodontically treated 60 mandibular incisor and 60 mandibular premolar teeth were used for the bond strength and fracture resistance test respectively. For each test, three groups (n = 20) were formed according to the posts used zirconia posts (ZR post), individually formed glass fiber reinforced composite posts with an (Interpenetrating Polymer Network-IPN post) and cast metal posts. Then groups were randomly assigned into two subgroups according to the post design: 1-parallel sided and 2-tapered (n = 10/group). All posts were luted with a self-adhesive luting agent. For push-out test two 1 mm thick horizontal root sections were obtained and subjected to push-out test. For fracture resistance test, the specimens were loaded vertically at 1 mm/min crosshead speed. The push out test data were analyzed with Kruskal-Wallis and Dunn's test. Analysis of variance (ANOVA) and Tukey significant difference tests were used to compare the fracture resistance. Cast metal posts showed the highest retention (p < 0.05); however, IPN and zirconia posts showed similar results. No significant difference was found between parallel sided or tapered designs of post groups in terms of bond strength (p > 0.05). In terms of fracture resistance, IPN post groups showed lowest fracture resistance (p < 0.05). No significant difference was found between parallel sided or tapered posts in terms of fracture resistance, except zirconia post (p > 0.05). There was no relationship between the bond strength and fracture resistance of the post systems (r = - 0.015, p > 0.700). Post type had effect both on the fracture resistance and retention of the posts used. However, post design had effect only on the fracture resistance of the post systems. Superficial treatment of the post used can improve the retention of post systems.