Evaluation of iliac and fibula graft reconstructions compared to healthy mandibles: A finite element analysis study

Mandibular continuity defects following tumor resection or trauma are commonly reconstructed using vascularized iliac crest or fibula grafts. The biomechanical implications of these grafts on implant-supported prosthetic rehabilitation remain unclear.

This study employed finite element analysis (FEA) to evaluate stress distribution in three mandibular models: a control model (CM), an iliac crest graft model (IM), and a fibula graft model (FM). A segmental defect was created from the right premolar to the mandibular angle and reconstructed using either iliac or fibula grafts. Each model received six implants, multi-unit abutments, and a bar-retained acrylic prosthesis. Simulations were performed under vertical loading in the central incisor, premolar, and molar regions. Von Mises stress values were analyzed in peri‑implant bone, implants, abutments, prostheses, and graft junction areas.

The highest stress values were observed in the fibula model under molar loading. Maximum peri‑implant stress in the posterior graft junction reached 39.483 MPa in FM, compared to 20.340 MPa in IM. Implant and prosthetic component stresses were also highest in FM under functional loading. Iliac models generally exhibited lower and more evenly distributed stresses across all conditions.

The type of graft significantly influences biomechanical performance in mandibular reconstructions. Fibula grafts demonstrated higher stress concentrations, particularly in posterior regions, suggesting potential long-term mechanical limitations. Iliac grafts provided more favorable stress distribution and may be preferable for posterior implant rehabilitation.