<![CDATA[Posterior tooth loss in the mandibular region may reduce masticatory performance and compromise biomechanical stability, thereby requiring predictable and well-designed implant rehabilitation strategies. This study evaluates the mechanical behavior of an implant–bone system by considering variations in bone material representation (isotropic and orthotropic models), implant–bone interface conditions (fully bonded and frictional contact), and loading orientations (axial and oblique) through a validated three-dimensional finite element analysis (3D-FEA) framework. A full factorial design comprising eight simulation configurations was implemented to assess 15 biomechanical output parameters, including von Mises stress, principal strain, and displacement across implant components and surrounding cortical and cancellous bone tissues. The results indicate that the biomechanical response of the system is strongly dependent on both structural components and loading context. The orthotropic bone model tends to increase stress and deformation responses under specific conditions, whereas oblique loading generally produces higher peak mechanical responses than axial loading. Furthermore, the influence of contact conditions is not uniform but varies according to material assumptions and loading direction, suggesting that simplified fully bonded interfaces may not fully capture realistic implant–bone interactions. Overall, the findings highlight the importance of incorporating anisotropic bone behavior, realistic interface modeling, and clinically relevant loading directions to improve the accuracy of stress prediction around dental implants. This study provides numerical evidence that may support improved implant design strategies and enhance the reliability of future finite element–based biomechanical investigations. ]]>
