Three Dimensional Finite Element Analysis of the Effect of Cavity Design Preparation and 3D Printed Resin Composite Restorations on Stress Distribution in Endodontically Treated Molars

Purpose: Analysis of the stress distribution in endodontically treated molars with different cavity designs that have been restored with 3D printed resin composite restorations under occlusal load using 3D finite element stress analysis (FEA).Methods: A 3D model of untreated intact maxillary first molar was created to act as a positive control group. Root canal treatment simulation was performed in six models that were designed for the same maxillary first molar studied, and then they divided taking into account the prepared cavity design (n=2); inlay, onlay and endocrown. The created six models received standardized MOD inlay cavity design. Reduction of both functional and non-functional cusps was performed with a 90-degree butt joint margin for preparation of onlay and endocrown models. Then, each simulated cavity design was divided into two sub groups according to the utilized restorative material (n=1); 3D printed and CAD/CAM resin composite. Vertical Force was applied, and then Von Mises (VM) stress values were evaluated at enamel, dentin, cement interface and restorative material using the FEA. Results: Endocrown cavity design showed the best distribution of stresses in the remaining tooth structure of endodontically treated teeth. CAD/CAM resin composite restorations absorbed higher VM stress values in comparison to models restored with 3D printed resin composite in each tested cavity design. Conclusion: CAD/CAM resin composite endocrown has been determined to be the most effective option for endodontically treated molar restoration among the examined restorations based on the distribution of stress in the remaining tooth structure and the cement interface.