骨駆動および咬合駆動による腓骨皮弁の顎骨再建における有限要素生体力学的比較

To evaluate, using finite-element analysis (FEA), the stress-strain state of mandibular bone and the bone component of a microvascular free fibula flap (FFF) reconstructing a lateral segmental mandibular defect, comparing two flap positions relevant to implant-supported fixed prosthetic rehabilitation.

CT-derived three-dimensional models of a reconstructed mandible were generated in two geometries: (A) flap aligned with the inferior mandibular border and (B) flap positioned at the level of the alveolar crest. Each geometry received two endosseous implants and a fixed prosthesis and was subjected to representative masticatory loading (vertical/occlusal and anterior/incisal). Four FEA models (2 positions × 2 load cases) were analyzed, with two predefined regions of interest per model (distal and medial), each examined at the upper and lower margins.

Compared with Model A (inferior mandibular border), Model B (alveolar crest) produced lower peak bone stresses in most analyzed regions (≈10-40% reduction) under mastication-representative static molar and incisal loads. The only exception was the medial-inferior margin under incisal loading, where stress increased markedly (8.96 vs 2.22 MPa; ∼4-fold). Under occlusal loading, medial-inferior stresses were <1 MPa in both models. Across both positioning scenarios, peak crestal bone von Mises stresses clustered near the implant neck (crestal bone); analyses were restricted to bone.

A higher (alveolar-crest) position of the bone component of the FFF yields a more favorable stress-strain environment and load distribution, supporting more favorable biomechanical conditions for osseointegration and long-term function.