Stress distribution in endocrowns with different materials and loading conditions: a FEM study.

Purpose: This study aimed to evaluate the effect of different restorative materials on stress distribution in endodontically treated teeth restored with endocrowns using the finite element analysis (FEA). Methods: Six test groups were defined according to restorative material: (1) polyetheretherketone (PEEK) with composite veneer, (2) carbon fiber-reinforced PEEK (CFR-PEEK) with composite veneer, (3) glass fiber-reinforced PEEK (GFR-PEEK) with composite veneer, (4) cobalt-chromium (Co-Cr) alloy with ceramic veneer, (5) monolithic lithium disilicate (LiDi) and (6) monolithic zirconium dioxide (Y-TZP). Mandibular molar models were designed in SolidWorks 2018 and Meshmixer and analyzed using ANSYS 16.0 under occlusal (400-600 N) and lateral (200-400 N) loading. Stress distribution in dentin was assessed using the von Mises criterion. Results: LiDi demonstrated a uniform and diffuse stress distribution with minimal peak variations, favoring its use under lateral loading. GFR-PEEK significantly reduced the dentin volume exposed to critical stress thresholds under high occlusal forces. In contrast, Co-Cr alloy and Y-TZP exhibited greater stiffness, resulting in less favorable stress transfer and pronounced concentration zones compared with PEEK-based materials and LiDi. Conclusions: The restorative material has a decisive influence on the biomechanical behavior of endocrowns. LiDi appears more suitable for premolars predominantly subjected to lateral forces, while GFR-PEEK offers superior protection in molars exposed to heavy occlusal loading.