Osteoconductivity of Zinc-Doped Calcium Phosphate Coating on a 3D-Printed Porous Implant

Currently, most of the commercial dental implants are made from inert pure titanium which facilitates osteointegration but without bioactive properties like osteo-conductivity and osteo-inductivity. Current attempts to improve dental implant bioactivity are limited by their single action and low efficiency. These methods either just add chemical coating on implants surface or simply change surface roughness instead of combining chemical and mechanical changes together. Here, we developed an advanced titanium implants by electro-depostion of a zinc-doped calcium phosphate (Zn-HA) coating on the 3D printed porous dental implants which optimize biomechanical and biological microenvironment for new bone formation. The bioactive titanium implants enable osteoblast-like cells to attach on implants, render high proliferation days 4 and 7 after attaching (P <0.001) and the following osteogenic differentiation indicated by increase alkaline phosphatase activity at 7 days post-seeding (P <0.001), total cellular protein expression at 14 days (P <0.05), osteogenic gene mRNA expression like OCN, RUNX2, and Osterix at days 9 and 14 (P <0.001) and protein bone sialoprotein and collagen I excretion at days 9, 14 and 21. Also we found out the optimal molar ratio of Zn/(Zn+Ca) for osteointergration around implants. Overall, Zn-HA on 3D printed porous titanium has good osteoconductivity, especially when Zn/(Zn+Ca) is 20%.