Failure Risk Estimating on Endocrown Restoration in Endodontically Treated Premolar

Objectives: The present study was aimed to evaluate the biomechanical failure risk behavior of an endodontically treated premolar with MOD preparation using different CAD/CAM ceramic restoring configurations. Methods: Three 3D finite element (FE) models of a maxillary premolar designed with endodontic treatment for MOD preparation restored with CAD/CAM ceramic inlay, endocrown and traditional crowns were constructed to perform simulations under axial load (100N) conditions. The Weibull function was incorporated with FE analysis to calculate the long-term failure probability relative to different load conditions (200 to 1500N) on three different restorations for endodontically treated premolars. Results: The results indicated that the maximum principal stress value in the remaining tooth for inlay restoration was almost 7 times those for endocrown and crown restorations. Subsequent Weibull analysis revealed that the failure probability for endocrown and crown restorations diminished more than that for inlay restorations when the load condition was smaller than 250N. However, the corresponding stress values and failure probability found did not exhibit obvious differences (<5%) between endocrown and crown restorations for all load conditions. Conclusion: This numerical investigation suggests that endocrown and crown restorations for endodontically treated premolars with MOD preparation present nearly the same longevity. Using the endocrown restoration presents the advantage of reducing the interfaces in the restorative system.