Effect of glass fiber on the restorative procedure in relation to fracture strength of endodontically treated molars

Aim: To evaluate whether the restorative procedure using glass fibers influence the fracture strength of endodontically treated molars with class II mesio-occlusal (MO) preparation. Methodology: Fifty human maxillary third molars were selected and randomly assigned to five groups (n=10). MO cavity preparation and endodontic treatment were standardized, except for the positive control group (S, sound teeth). The other groups were classified as: ET, no restoration (negative control); SF, restoration with SonicFill 2 (R) system; SFB, restoration with braided glass fiber and SonicFill 2 (R) system; and SFP, restoration with transfixed glass fiber post and SonicFill 2 (R) system. The specimens were subjected to fracture strength testing on a universal testing machine. Fracture site - either pulp chamber floor or cusp - was inspected. Statistical analysis was performed using ANOVA, followed by Tukey's multiple comparison test (alpha=5%). Results: Means followed by the same letter did not show statistical difference in Tukey's test (P>0.05). S: 3563A +/- 780.7; ET: 1001D +/- 237.6; SF: 1689C +/- 280.7; SFB: 2256B +/- 289.2; and SFP: 2493B +/- 364. Conclusions: The glass fiber, regardless of composition, increases the fracture strength of endodontically treated teeth. The use of a glass fiber post attached to the dental crown seems to provide more favorable rehabilitation when the fracture position is determined.