In Vivo Effect of Titanium Implants with Porous Zinc-Containing Coatings Prepared by Plasma Electrolytic Oxidation Method on Osseointegration in Rabbits

Purpose: The aim of this study was to confirm the in vivo effect of surface-modified titanium (Ti) implants with zinc (Zn) prepared by a plasma electrolytic oxidation (PEO) method on the process of osseointegration. Materials and Methods: Forty-five New Zealand white rabbits were used. Implants were divided into three groups due to different surface treatments (the PEO-Zn group, the PEO-calcium phosphorus [Ca/P] group, and the sandblasted [control] group) and were randomly inserted into rabbits' mandibles. The implant surface morphology and chemical state of the relevant elements were observed. The maximum push-out force, the bone-to-implant contact (BIC), and the mineral apposition ratio (MAR) were detected at 4, 8, and 12 weeks after implantation. Results: A two-layer structure, with a dense inner layer and a porous outer layer, was found in the PEO samples. In the PEO-Zn group, CaHPO4 center dot 2H(2)O (dicalcium phosphate dihydrate) was the main calcium compound, and ZnO was identified as the predominant form of Zn. More bone deposition was found on the top of the PEO-Zn implant, which was also confirmed by scanning electron microscope (SEM) afterward, and the shear strength reached a maximum value of 1.57 +/- 0.26 MPa at 12 weeks compared with the sandblasted group and the PEO-Ca/P group. The BIC values and the MARs of the PEO-Zn group were significantly higher than the control group, especially at the early weeks (P < .05), and first reached maximum values of 73.91% +/- 9.01% and 4.89 +/- 0.60 mu m/d at 12 weeks, respectively. Conclusion: Implants with Zn coating by the PEO method could accelerate bone formation and bone remodeling, shorten the osseointegration period, and enhance bone-implant bonding force.