Quantifying Stress Shielding in Dental Implants: A Comparative Finite Element Study of Titanium, CFR-PEEK, and...

Background: Stress shielding, which occurs when there is a mismatch between the stiffness of the implant and the bone, can alter load transfer and drive peri-implant bone remodeling, particularly in low-density bone. Methods: We compared the biomechanical responses of one-piece implants made of Ti-6Al-4V, Y-TZP, and CFR-PEEK. We modelled the bone as linearly isotropic in the transverse direction and the implants as linearly isotropic with a fully bonded interface. A static load of 200 N was applied at an inclination of 30° buccal-to-lingual, with the transverse bone bottom faces fully constrained. Results: The peak cortical von Mises stress was highest for Y-TZP (87 MPa), followed by Ti-6Al-4V (57 MPa) and CFR-PEEK (approximately 37 MPa). Peak cortical von Mises strain showed the same relative order of magnitude: 3450 µε, 3103 µε, and 1523 µε, respectively. The stress-shielding factor (SSF) revealed that shielding was present in the mid-apical regions. Y-TZP exhibited the greatest shielding (SSF: 0.844-0.877), followed by Ti-6Al-4V (SSF: 0.380-0.568) and CFR-PEEK (SSF: 0.375-0.437). No crestal shielding was observed (SSF < 0). Conclusions: Overall, implants with higher stiffness increased crestal stress concentration and deepened peri-implant shielding. Meanwhile, CFR-PEEK improved load sharing and produced a more homogeneous mechanical stimulus in low-density bone.