Osseointegration Effects of 3D-Printed Porous Titanium-Tantalum Scaffolds with Different Tantalum Contents.

Titanium (Ti) is known for its excellent corrosion resistance and its biomechanical properties. However, its bioinert nature and high elasticity result in suboptimal osseointegration. In contrast, tantalum (Ta) demonstrates superior osteogenesis and osseointegration but has a high elastic modulus and density, making it costly to process. In the present study, we produced the implantable composite TiTa that combines the advantages of Ti and Ta, which is fabricated by blending Ti powder with 25, 50, and 75% Ta. We designed porous scaffolds with different TiTa ratios while maintaining consistent porosity, pore shape, pore size, and distribution via computer-assisted design (CAD) and fabrication through laser powder bed fusion (LPBF). The results show that the elastic modulus and yield stress of TiTa scaffolds both match the mechanical environment characteristics of human cancellous bone, which can reduce the risk of stress shielding. In vitro experiments showed that TiTa50 and TiTa75 had cell adhesion, proliferation, and osteogenic differentiation abilities comparable to those of Ta in MC3T3-E1 cells. Furthermore, in vivo studies revealed that TiTa50 and TiTa75 achieved bone formation and osseointegration capabilities similar to those of Ta. This indicates that TiTa alloys with up to 50% Ta can achieve osseointegration comparable to that of Ta. Notably, compared to TiTa75, TiTa50 contains a lower proportion of Ta. It not only effectively balances the alloy's processability and formability while safeguarding its bioactivity but also offers substantial cost-saving potential. Consequently, TiTa50 is easier in terms of the preparation process and more cost-effective compared to TiTa75.