Assessment of Fracture Resistance of Endodontically Treated Molars Restored with Endocrowns Fabricated by Two different Materials - In-vitro Study

Abstract

The aim of this study was to assess the fracture resistance of endodontically treated molars restored with endocrowns fabricated by pressed lithium disilicate and nanohybrid composites cemented by conventional etch and rinse resin cement. Materials and Methods: Forty sound permanent lower second molars were assigned into four equal groups according to the restorative material used for endocrown fabrication; Group (1): sound molars as negative control (sound), Group (2): molars were endodontically treated and received occluso-mesial cavities without restorations as a positive control (unrestored), Group (3): molars were endodontically treated and received occluso-mesial cavities restored using lithium disilicate endocrowns (LDS) and Group (4): molars were endodontically treated with occluso-mesial cavities restored using nanohybrid composite endocrowns (NRC). Endocrowns were fabricated and cemented using conventional resin cement. Fracture resistance of all groups was evaluated using universal testing machine. Results: One-way ANOVA showed a statistically significant difference between groups with p< 0.001. Sound teeth recorded the highest mean fracture resistance sound teeth recorded the highest mean fracture resistance (2064.29 ± 446.25 N), followed by NRC group (1831.03 ± 403.09 N) then LDS group (1551.54 ± 153.70 N), with statistically insignificant difference between the three groups. While unrestored teeth recorded the least statistically significant mean fracture resistance(632.15± 247.61 N). Conclusions: Fracture resistance of both nanohybrid resin composite endocrowns and lithium disilicate endocrowns was similar to that of intact teeth. Clinical relevance: Nanohybrid resin composite endocrowns and lithium disilicate endocrowns can be used to restore ETT with occlusomesial cavities.