Gyroid porous titanium structures: A versatile solution to be used as scaffolds in bone defect reconstruction

Abstract

Triply periodic minimal surfaces (TPMS) have emerged as a suitable tool for designing porous biomaterials. One of the well-known TPMS structures is the gyroid structure. Different types of gyroid porous structures (normal and deformed gyroid structures) with different porosities have been designed and fabricated by Electron Beam Melting technology with the purpose of analysing the mechanical properties under compression and torsion loads. Then, some of them have also been studied by finite element method for different load directions. The compression tests demonstrated that the deformed gyroids presented high stiffness and strength with loads in the longitudinal direction of the structures, especially when the deformed gyroids were reinforced with a shell. The torsion tests showed that the normal gyroids presented better torsional stiffness and strength than the deformed gyroids, with high CAD porosities (90%). However, no significant differences between both structures were found for low CAD porosities (75%). Finite element analysis showed that when the loads adopted a 45 degrees angle with regard to the longitudinal axis of the structure, the normal gyroids presented more homogeneous behaviour than the deformed gyroids. In summary, gyroid porous titanium structures presented good and versatile stiffness and strength to be used for correction of bone defects.