Benito Alston : 3D printed guided bone regeneration (GBR) graft optimized through finite element analysis (FEA)
3D printed guided bone regeneration (GBR) graft optimized through finite element analysis (FEA)
Claudia Benito Alston
Claudia Benito Alston1, Nicanor Moldovan2, Clark Barco2, Luis Solorio1
1 Weldon School of Biomedical Engineering, Purdue University, 2 Richard L. Roudebush VA Medical Center
Guided bone regeneration utilizes bone particulates surrounded by titanium or collagen mesh encasing in order to reconstruct bone defects. In this study, we explored dual-component constructs through a pre-surgical 3D printed patient specific design. Finite element analysis (FEA) was utilized to compare the impact of screws, cover porosity and core material during mastication. The end goal was to design a cover and core construct that could sustain mastication, limit stress shielding, and allow for cell infiltration early in the regeneration cascade.
A graft was designed to fit an open source mandible model with a defect. Simulations utilized a downward 250N masticatory force, and a 24N bolt preload while fixed along the mandible’s inferior edge. The graft was assumed to be bonded. Outputs included stress, strain, von mises stress and deformation.
Results show that porous covers with a hydrogel core, which allow for cell infiltration, could sustain mastication without yielding but also begin to fall within the region of limiting stress shielding which is 20 – 60 MPa. Comparing hydrogel and solid cores, significant differences across all parameters can be seen. Furthermore, increasing the elastic modulus of hydrogel cores will allow the cover to transmit further stress to the core, improving bone regeneration through Wolff’s law. Comparing lingual screws to buccal screws, showed little to no effect on parameter outputs.
Through FEA the viability of a porous 3D printed cover and core graft with buccal screws was demonstrated. The large effect that a solid core had on the model demonstrated the importance of a softer core for modulating stress shielding while ensuring the cover would minimally deform.
Translational/Human Health Impact:
The current standard of care is designed in vivo leading to longer surgical times, unreproducible porosities, requiring the core material to be structurally sound to sustain possible mastication. Pre-surgically tuning a cover and core construct and 3D printing remedy these problems, while improving bone regeneration.