Comparative evaluation of fracture toughness and marginal adaptation of two restorative materials in nonendodontically and endodontically treated teeth: An in vitro study.

Objective: To evaluate and compare the fracture resistance and marginal adaptation of Zirconomer and bulk fill posterior restorative material (Surefil SDR) in nonendodontically and endodontically treated teeth. Materials and Methods: The sample consisted of 52 caries-free extracted human premolars which were individually mounted in polyvinyl chloride (PVC) ring filled with acrylic resin up to 1.0 mm below the cementoenamel junction. The teeth were then divided into four groups according to the restorative material used as group I: Zirconomer + Operative only, Group II: Zirconomer + Endodontic treatment, Group III: SDR + Operative, and Group IV: SDR + Endodontic treatment. Fracture strength was tested using a universal testing machine and was expressed in Newtons. The marginal gap was measured at its maximum using a scanning electron microscope and expressed in micrometers. One-way analysis of variance followed by Tukey's post hoc test was used to compare the mean fracture resistance (N) and marginal adaptation (mum) between the four groups. Statistical significance was determined at alpha = 0.05. Results: Group 3 exhibited significantly highest mean fracture resistance than Group 1 (P < 0.001), Group 2 (P < 0.001), and Group 4 (P < 0.001). Group 4 had significantly higher mean fracture resistance than Group 1 (P = 0.008) and Group 2 (P < 0.001). Group 1 exhibited significantly highest mean marginal gap than Group 3 (P < 0.001) and Group 4 (P < 0.001). Group 2 had a significantly higher mean marginal gap than Group 3 (P < 0.001) and Group 4 (P < 0.001). Conclusion: The fracture resistance and marginal adaptation of Zirconomer are significantly lower than Surefil SDR in both nonendodontically and endodontically treated teeth.