Comparison of Two Types of Patient Specific Implants (PSI) and Quad Zygoma Implant (QZI) for Rehabilitation of Post-COVID Maxillary Mucormycosis Defect (PCMMD): Finite Element Analysis

Abstract

Introduction: The residual post-COVID maxillary mucormycosis defect (PCMMD) were extensive, due to unilateral or bilateral maxillectomies. The Goal of rehabilitation of PCMMD is to deliver a prosthetically driven reconstruction. FEA was to evaluate the biomechanical response of PSI struts (PSI 1), PSI Screw retained (PSI 2) and QZI to masticatory load on virtual simulation to improve accuracy and enhance the design.

Aim: To validate and compare the Biomechanical benefit of the PSI struts, PSI Screw retained, QZI in a case of rehabilitation of post-COVID maxillary mucormycosis defect (PCMMD) by FEA study.

Methodology: The result of stress to masticatory load on virtual simulation for (1) Maximum and minimum stress (Von Mises stress); (2) the Displacement (in three positions) and (3) the Deformation (Plastic strain) was compared on virtual simulation for PSI 1 and PSI 2 and QZI.

Conclusion: The FEA and comparative evaluation of PSI 1, PSI 2 and QZI showed a good resistance to displacement. The stress and strain values are low and acceptable. In comparison QZI shows more stress in the anterior region.

Keywords: Additive manufacturing; Biomechanical analysis; Finite element analysis; Maxillary reconstruction; Patient-specific implant; Structural optimization.

Fig. 1

3-D CT image of a case for FEA

Fig. 2

Design of implants and direction of masticatory force for simulation. A PSI 1; B PSI 2; C QZI

Fig. 3

Von Mises stress image showing the deformation scale in colour coding the minimum is dark blue. A PSI 1; B PSI 2; C QZI

Fig. 4

Displacement seen on deformation scale with colour coding, the minimum—dark blue and maximum—red. A PSI 1; B PSI 2; C QZI

Fig. 5

Plastic strain seen on deformation scale with colour coding,the minimum—dark blue. A PSI 1; B PSI 2; C QZI