Introduction: Endocrown restorations offer a promising alternative to restore endodontically treated teeth. However, various materials are available without being thoroughly evaluated.
Purpose: The purpose of the study is to evaluate marginal fit and fracture resistance of endocrown restorations using three CAD-CAM materials.
Materials and Methods: Eighteen freshly extracted human permanent mandibular first molars were prepared to receive endocrown restoration. Teeth were randomly allocated into three groups according to material type (n=6). (LD): Lithium Disilicate, (FCZ): full contour zirconia, (RNC): resin nanoceramic. All Endocrown restorations were fabricated by using CAD-CAM. Restorations were adhesively luted to the corresponding prepared teeth and subjected to thermomechanical cycling corresponding to six months of clinical service. Marginal gap was measured before cementation and after cementation and aging using optical microscope. For measuring fracture resistance, specimens were loaded till failure by using Universal Testing Machine. Failure mode analysis was evaluated by optical microscope. Fracture resistance was analyzed by One-Way ANOVA and Tukey's post hoc test while marginal gap was analyzed by Two-way ANOVA and Tukey's post hoc test.
Results: FCZ had the highest fracture load compared to RNC and LD. Zirconia recorded largest microgaps before cementation.
Conclusion: FCZ showed the highest values of fracture resistance. LD and RNC ceramics showed comparable fracture resistance values favoring their use as endocrown restorations. The tested groups showed marginal fit results within the limits of clinically acceptable standards. The material type and thermomechanical aging had a significant effect on marginal gap.