Mechanical Properties of Porous Structures for Dental Implants: Experimental Study and Computational Homogenization

Abstract

A combined experimental and numerical study on titanium porous microstructures intended to interface the bone tissue and the solid homogeneous part of a modern dental implant is presented. A specific class of trabecular geometries is compared to a gyroid structure. Limitations associated with the application of the adopted selective laser melting technology to small microstructures with a pore size of 500 μm are first examined experimentally. The measured effective elastic properties of trabecular structures made of Ti6Al4V material support the computational framework based on homogenization with the difference between the measured and predicted Young’s moduli of the Dode Thick structure being less than 5%. In this regard, the extended finite element method is promoted, particularly in light of the complex sheet gyroid studied next. While for plastic material-based structures a close match between experiments and simulations was observed, an order of magnitude difference was encountered for titanium specimens. This calls for further study and we expect to reconcile this inconsistency with the help of computational microtomography.

Numerical simulations of gyroid structures under compressive loads

“…Additionally, the resolution of the printing machine should be considered to obtain a specimen that follows the theoretical shape of the gyroid structure. However, specimens with small unit cells imply that the edge effects influence the mechanical behavior of the structure [19]. Further, specimens with significantly small thicknesses/volume fractions cannot be printed because of the resolution of the printer.…”

“…The main drawback of the nTopology software is that orthotropic and isotropic materials can only be simulated as elastic materials. Nevertheless, nTopology integrates a homogenization module that enables the simulation of a unit cell under different load cells to obtain the equivalent mechanical properties [19,20]. Subsequently, a larger structure comprising many of these unit cells can be simulated, without meshing the actual geometry of the structure.…”

“…Studies by various authors [17][18][19] have revealed that the homogenization method is useful for determining elastic properties with a relatively low computational cost.…”