Modelling subcortical bone in finite element analyses: A validation and sensitivity study in the macaque mandible

Area of Science:

• Biomechanics
• Computational modeling
• Materials science

Background:

• Finite element analysis (FEA) is crucial for studying stress and strain in complex structures.
• The accuracy of FEA models heavily depends on the precision of the input geometry.
• Computed tomography (CT) aids in geometry acquisition, but subcortical bone details can be limited by image resolution.

Purpose of the Study:

• To investigate the impact of subcortical geometry variations on FEA predictions of mandibular biomechanics.
• To determine if subcortical bone structures need explicit modeling in FEA for accurate results.
• To assess the sensitivity of FEA strain outcomes to subcortical geometric complexity.

Main Methods:

• Developed multiple finite element (FE) models of a macaque mandible with varying subcortical geometries.
• Performed experimental strain measurements on the actual mandible to validate FE model predictions.
• Compared FEA-derived strain magnitudes and orientations across different subcortical models.

Main Results:

• FE model predictions closely matched experimental strain measurements, confirming model validity.
• Cortical bone alone is less effective at resisting bending forces compared to when coupled with subcortical bone.
• Subcortical geometries significantly influence the mechanical response of the mandible during FEA.

Conclusions:

• Accurate modeling of subcortical bone is essential for reliable FEA of complex structures like the mandible.
• Subcortical bone structures can be adequately represented as a solid material with an appropriate Young's modulus (1-2 GPa) in FEA.
• This finding is significant for creating FE models of bone where high-resolution imaging of subcortical regions is challenging.