Stress Distribution in Endocrowns with Different Materials and Loading Conditions: A Finite Element Analysis 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) method. 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.