Influence of Immediate Versus Delayed Loading on Peri-Implant Bone Healing: A Comparative FEA Study of Titanium Threaded and Scaffold Dental Implants

BACKGROUND: Immediate loading of dental implants shortens treatment time and improves early function, but it also exposes the healing peri-implant tissue to a critical mechanical environment. This study compared the biomechanical and mechanobiological response of a conventional threaded implant and a porous scaffold-based implant under immediate and delayed loading conditions. METHODS: A three-dimensional finite element model of a bone block with a 0.2 mm peri-implant callus was developed in ABAQUS/Standard. Model A was a threaded Ti-6Al-4V implant, while Model B was a porous implant with 64.26% porosity. Bone tissues were modeled as poroelastic materials. Immediate and delayed loading were simulated through frictional and tied bone-implant interfaces, respectively. Mechanobiological predictions were performed using the Prendergast-Huiskes stimulus. RESULTS: Under immediate loading, the porous implant reduced cortical bone stress (32.5 MPa vs. 88 MPa) and markedly increased callus stimulation (20.5-31.6 MPa vs. about 2.5 MPa) compared with the threaded implant. Mechanobiological analysis showed that Model B promoted higher fractions of immature and mature bone and lower fractions of cartilage and fibrous tissue. In all cases, implant stresses remained below the yield strength of the corresponding materials. CONCLUSIONS: The porous implant provided a more favorable mechanical environment for early peri-implant healing, particularly under immediate loading, and may be a promising strategy to enhance callus maturation and reduce stress shielding.