Effect of Prosthodontic Material on Stress Distribution in Posterior Single Crown Supported by the Bioxide-S Symbionic Tooth: Influence of Bone Architecture in a Three-Dimensional Finite Element Analysis

Background/Objectives: The biomechanical response of posterior single crowns is influenced by restorative stiffness, device geometry, loading direction, and bone architecture. This study evaluated the effect of crown material on stress distribution in posterior single crowns supported by the Bioxide-S Symbionic Tooth (ST) under two idealized bone architectures. Methods: Twelve three-dimensional static finite element models were generated by combining two ST configurations (premolar: 4.1 × 11 mm; molar: 5.0 × 11 mm), three crown materials (zirconia, IPS e.max lithium disilicate, and GC Cerasmart resin-matrix ceramic), and either a cortical–cancellous or an all-cortical bone model simulating Misch D1 conditions. A 200 N oblique load at 20° was applied to the premolar models, whereas a 400 N axial load was applied to the molar models. Results: Zirconia consistently produced the highest global equivalent von Mises stress, IPS e.max produced intermediate values, and GC Cerasmart produced the lowest. Bone architecture had a limited effect in molar models but a greater, material-dependent influence in premolar configurations. Stress concentrations were mainly observed at the cervical ST region, crown–post–device transition, first threads, and crestal cortical bone. Conclusions: These findings indicate that crown material substantially influences stress redistribution within the modeled system, whereas the effect of bone architecture is more configuration-dependent. The results should be interpreted as comparative biomechanical trends rather than predictors of material failure or clinical performance.