FRACTURE RESISTANCE AND MARGINAL FIT OF ENDOCROWN RESTORATIONS USING THREE DIFFERENT CAD-CAM MATERIALS

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 extracted permanent mandibular molars were selected to receive endocrown restoration. Teeth were randomly allocated into three groups based on material type (n=6). (LD): Lithium Disilicate, (FCZ): full contour zirconia, (RNC): resin nanoceramic. All Endocrown restorations were fabricated utilizing CAD-CAM technology. 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, samples were loaded till fracture occurs by using Universal Testing Machine. Optical microscope was used to evaluate mode of failure. One-way ANOVA and Tukey's post hoc test were used to analyze fracture resistance, while Two-way ANOVA and Tukey's post hoc test were used to analyze marginal gap. RESULTS: FCZ had the highest fracture load compared to RNC and LD. Zirconia recorded largest microgaps before cementation. CONCLUSION: FCZ showed the highest fracture resistance values. LD and RNC ceramics showed fracture resistance with comparable values recommending their use as endocrown restorations. The tested groups showed marginal fit results within the bounds of clinically acceptable parameters. The material type and artificial aging process had a significant impact on the marginal gap.