[Study of relationship between different contents of zinc and antibacterial activity on calcium phosphate coating...

Calcium phosphate activity coating containing different contents of zinc was deposited onto the surface of pure titanium modified by plasma electrolytic oxidation. The physical and chemical properties of different contents of zinc were compared among three groups, and the influence on antibacterial activity of P.gingivalis (Pg) and A.actinomycetemcomitans (Aa) was evaluated.

Pure titanium samples were treated in the electrolyte of plasma electrolytic oxidation with 0.08 mol/L calcium and 0.06 mol/L phosphorus, and 0.01, 0.03, 0.05 zinc was added to each group in order to deal with pure titanium plate. Titanium samples were divided into three groups: low, middle and high group according to zinc contents. The group without zinc was as control. The binding force of coating and titanium was tested by electric universal test machine. The topography of surfaces was observed under scanning electron microscope (SEM). The crystalline structure of surfaces was determined by XRD. The chemistry and elements of surfaces were determined by XPS. Pg and Aa were seeded onto samples surfaces, and the antibacterial properties of four kinds of materials were evaluated by using scanning electron microscopy and the paster method. Statistical analysis was performed using SPSS 13.0 software package.

It was found that the aperture and roughness were increased with the increase of content of zinc. The crystallization of low zinc group was superior to high zinc group. The content of HA and Zn3P2 in low zinc group was more, but ZnO in high zinc group was more. Scanning electron microscope demonstrated that the number of Pg and Aa decreased on the surface with the increase of the content of zinc, while the bacteria of high zinc group underwent lysis and necrosis. By using the paster method, the number of Pg and Aa decreased on the surface with the increase of the content of zinc, and there was significant difference among the four groups.

The change of zinc content will change the physical and chemical properties of the coating; at the same time, the antimicrobial property of calcium phosphate coating with high content zinc was the best.