Biomechanical evaluation of shape-optimized CAD/CAM magnesium plates for mandibular reconstruction

Magnesium CAD/CAM miniplates are a promising alternative to titanium plates for mandibular reconstruction. However, gas formation is an inherent part of the magnesium degradation process, and thus, the quantity of magnesium used in fixation scenarios should be limited. Previous studies described several strategies to limit material volume, such as plate thickness reduction and shape-optimization. In particular, shape-optimization has been described as a strategy to limit material volume while maintaining mechanical integrity. In consequence, the present study compared a shape-optimized CAD/CAM magnesium miniplate with standard CAD/CAM magnesium miniplates of varying thicknesses using a biomechanical finite element model. A single-segment mandibular reconstruction was chosen as the investigative scenario, evaluated under different biting tasks to assess the different plate shapes. The shape-optimized magnesium plate demonstrated similar primary fixation stability compared to standard CAD/CAM magnesium miniplates, despite having reduced plate material and surface area. Shape optimization could help minimize magnesium volume and surface area to mitigate the issue of gas formation during the degradation process in vivo while maintaining biomechanical performance comparable to common CAD/CAM miniplates.