3D Printing of Optimized Titanium Scaffold for Bone Replacement

Critical-sized bone defects or CSDs results from bone loss due to trauma, tumour removal, congenital defects or degenerative diseases. Though autologous bone transplantation is the current gold standard in treating CSDs, its limitations include donor-site morbidity, unavailability of donor bone tissues, risk of infection, and mismatch between the bone geometry and the defect site. Customized scaffolds fabricated using 3D printing and biocompatible materials can provide mechanical integrity and facilitates osseointegration. Ti-6Al-4V aka Ti64 is one of the most widely used commercial alloys in orthopedics. To avoid elastic modulus mismatch between bones and Ti64, it is imperative to use porous lattice structures. Porous lattices using diamond, cubic and TPMS (triply periodic minimal surface) gyroid unit cells were designed for 300, 600 and 900 µm pore sizes and 3D printed using selective laser melting (SLM). Compression and in-vitro tests were conducted to study the impact of pore size and unit cell variation on mechanical and biological behaviour. Results showed that the compressive properties decreased with increase in pore sizes. The biological evaluation reported maximum cell adherence in lower pore sizes with gyroid samples exhibiting statistically significant (p < 0.01) increase in cell proliferation.