Fracture strength of different remaining dentin restored with fiber-reinforced posts

Objectives:The aim of this study was to evaluate the fracture strength of bovine teeth adhesively restored with fiber-reinforced composite with different quantity of remaining dentin. Material and Method: Thirty single-rooted bovine teeth (22 mm length) were prepared at 18 mm, using burs of FRC Postec system (Ivoclar). The cervical portion of the specimens were prepared for a total crown restoration (height: 6 mm; Ø= 4mm). These prepared teeth were divided into 3 testing groups (n=10) according to the height of remaining dentin: (G1) 2 mm above the prepared finish line; (G2) 4 mm above the prepared finish line; (G3) no remaining dentin above the prepared finish line. The dentin was treated with All-Bond 2 adhesive system and the fiber posts were cemented with DuoLink resin cement (Bisco). The cores were constructed using a hybrid composite resin, using plastic molds. The specimens were submitted to 1 million mechanical cycles (load: 50 N; angle of 45 degrees) and the tested until fracture in a universal testing machine (Instron). Results: No specimens failed during the load cycles One-way ANOVA and Tukey test (=.05) indicated that the fracture strength of G2 (media; standard deviation/ 604,98; 147,72) was statistically superior than G3 (442,29; 92,96), and G1 (516;111,32) presented intermediated values that was not statistically different from the other groups. Conclusion: The fracture strength depends on the quantity of the remaining dentin.