Fracture resistance of endodontically treated premolars restored with direct fiberglass-reinforced composite in MOD cavities.

Introduction: Direct composite restorations in endodontically treated teeth preserve tooth structure. The objective of this study was to evaluate fracture resistance of premolars with MOD preparation and endodontic treatment restored with composite resin and reinforced with fiberglass tape occlusally or interproximally. Methods: N = 33 sound human upper premolars with similar dimensions were selected. The teeth were randomly divided into 3 groups (n=11), with the control group not receiving any endontontic or restorative preparation. The remaining 2 groups were GO: teeth with endodontic treatment, MOD preparation and cusp coverage with fiberglass tape applied to the occlusal surface and GP: teeth with endodontic treatment, MOD preparation without cusp coverage, but fiberglass tape applied mesially and distally to restore the marginal ridges. All 33 teeth were embedded in acrylic resin and underwent fracture strength test in a universal testing machine (0.1 mm/minute) until fracture. The fracture pattern was classified into four types (I, II, III and IV). The fracture resistance values were analyzed using one-way ANOVA (p