Evaluation of the stress after marginal mandibular resection with and without plates in different residual bone heights: A 3D Finite element analysis

Abstract

Purpose

This study aims to evaluate the biomechanical stability of the mandible following marginal mandibular resection (MMR) with varying levels of residual bone height, using finite element analysis (FEA), and to assess the influence of reconstruction plate application on stress distribution during functional loading.

Materials and Methods

Finite element models simulating MMR on the left mandible were generated with residual bone heights of 3 mm, 5 mm, and 7 mm (two models per height). These were divided into two groups: one with a reconstruction plate and one without. Simulated masticatory muscle forces were applied to mimic incisal clenching (INC) and right first molar clenching (RMOL). Maximum and minimum principal stress values within the mandible were recorded.

Results

Under RMOL loading, microdamage thresholds were exceeded in non-plate models with 3 and 5 mm heights, and in all plate-applied models. The only model not exceeding the microdamage threshold was the non-plate model with a 7 mm residual bone height, showing 38.77 MPa and 57.83 MPa in cortical bone during INC and RMOL, respectively. Plate-applied models showed higher maximum principal stresses, while non-plate models had higher minimum principal stresses.

Conclusion

A residual bone height of 7 mm without plate application appears biomechanically sufficient to withstand physiological masticatory loads without initiating microdamage. These findings may assist maxillofacial surgeons in determining the necessity of plate reconstruction in select clinical scenarios, potentially reducing surgical complexity and hardware-related complications.