Additive manufacturing of functionally graded porous titanium scaffolds for dental applications

Graded porous titanium scaffolds are gaining increasing attention as dental implants due to their ability to mimic the mechanical and biological properties of human bone. In this study, we have developed titanium scaffolds with graded primitive structures with porosities of 50.7 %, 61.0 %, 70.5 %, and 80.3 % (denoted as P50, P60, P70, and P80, respectively) for dental applications. The simulation results in the oral environment showed that the maximum von Mises strains and stress of cortical bone tissue around P50, P60, and P70 were lower than 3000 με and 60 MPa, respectively, which was beneficial for bone regeneration. The elastic modulus and yield strength of P50, P60, and P70 ranged within 5.2-13.8 GPa and 88.6-217.8 MPa, respectively. Among these, P60 exhibited the most favorable mechanical properties with a compression yield strength of 163.2 MPa and an elastic modulus of 9.7 GPa, which are desirable mechanical properties for dental material applications. The tested permeabilities of the fabricated specimens were in the range 0.66-6.88 × 10^-9 m², which is within the range of human bone (0.01-12.10 × 10^-9 m²). In vitro biocompatibility assay results showed that P60 and P70 had better potential for cell viability and osteogenesis than P50. It can be concluded that P60, which has a compatible elastic modulus, high yield strength, high permeability, good cytocompatibility, and osteogenesis properties, is a promising candidate for bone-tissue engineering applications in dentistry.