How does the Number of Implants Affect Stress Distribution in Fibula Graft at the Posterior of the Mandible? A Finite Element Analysis.

[OBJECTIVES] Evidence about the implant protocol and success in the osseous microvascular grafts is not sufficient. Stress distribution around dental implants is one of the important factors determining treatment success. The purpose of this study was to evaluate stress distribution in the bone supporting the implants inserted in the fibula free flap, in patients with large defects in the posterior of the mandible by finite element analysis (FEA).

[MATERIALS AND METHODS] The CBCT was obtained from one patient with fibula free flap in the posterior of the mandible and also from a 4.1 × 10 mm implant (Zimmer, Zimmer dental, Carlsbad, USA). Two 3D finite models were designed containing three or four implants. The implants were splinted by a suprastructure. Vertical load (300 N) and oblique load (50 N) were applied to the suprastructure. The von Mises stress distribution and the micromotion of implants were evaluated.

[RESULTS] No significant difference was observed between implants micromotion in two models. According to stress distribution analysis and determining maximum stress regions, the model with four implants imposes more stress on titanium components and surrounding bone.

[CONCLUSION] The stress distribution around the implants of mandibular models with posterior defect that was reconstructed with fibula free flap is better in models with three fixtures versus four fixtures.