Comparison of titanium dioxide scaffold with commercial bone graft materials through micro-finite element modelling in flow perfusion.

TiO2 scaffolds have previously shown to have promising osteoconductive properties in previous in vivo experiments. Appropriate mechanical stimuli can further promote this osteoconductive behaviour. However, the complex mechanical environment and the mechanical stimuli enhancing bone regeneration for porous bioceramics have not yet been fully elucidated. This paper aims to compare and evaluate mechanical environment of TiO2 scaffold with three commercial CaP biomaterials, i.e. Bio-Oss, Cerabone and Maxresorb under simulated perfusion culture conditions. The solid phase and fluid phase were modelled as linear elastic material and Newtonian fluid, respectively. The mechanical stimulus was analysed within these porous scaffolds quantitatively. The results showed that the TiO2 had nearly heterogeneous stress distributions, however lower effective Young's modulus than Cerabone and Maxresorb. The permeability and wall shear stress (WSS) for the TiO2 scaffold was significantly higher than other commercial bone substitute materials. Maxresorb and Bio-Oss showed lowest permeability and local areas of very high WSS. The detailed description of the mechanical performance of these scaffolds could help researchers to predict cell behaviour and to select the most appropriate scaffold for different in vitro and in vivo performances. Graphical abstract Schematic representation of the establishment procedure. Take the establishment process of Cerabone as an example. Left shows a slice of micro-CT image from Cerabone, and 1.5 mm × 1.5 mm region of interest was shown in the red box. A 1.5-mm3 cube was cut out by Boolean operation in Mimics (Materialise, Belgium), and the cubic model was remeshed in 3-Matic 6.0 (Materialise, Belgium). The cubic model is shown in blue, and the empty space in red.