Fracture Resistance of Endodontically Treated Mandibular Molars Restored With Two Endocrown Designs (An In-Vitro Study)

Aim: To evaluate the effect of two endocrown designs on the fracture resistance of endodontically treated mandibular molars.Materials and methods: Fourteen mandibular molars were endodontically treated and randomly divided into two groups according to the endocrown design; group (A) Axial extension (n=7) and group (B) Circumferential extension (n=7). Endocrown preparation was done followed by CAD/CAM endocowns design and fabrication using lithium disilicate glass ceramics. Endocrowns were cemented using a standardized protocol. All samples were subjected to fracture resistance test using a universal testing machine and the maximum loaded was recorded. Statistical analysis was performed using One-Way ANOVA and significance level was set at 0.05.Results: Endodontically treated mandibular molars with axial extension endocrowns showed significantly higher fracture resistance than those with circumferential extension. Conclusions: Axial extension endocrown design is recommended to restore endodontically treated mandibular molars.