Abstract: Objective To systematically evaluate the effect of propolis's solution in killing periodontal main pathogenic bacteria,and identify the mechanisms of sterilization and decontamination of surfaces of contaminated titanium surfaces.Methods Decontamination effect of propolis on Porphyromonas gingivalis was determined by the fluid dilution method,and subsequently inoculated with the bacteria of Porphyromonas gingivalis. The bacteria in specimens were counted by colony-forming units and sterilization rate. The titanium disc were incubated in Porphyromonas gingivalis suspension.The bacterial morphology of each group were characterized by scanning electron microscopy.Results With the extension of the propolis solution concentration,reduce the number of its colonies were found. Colony count at different concentrations there were significant differences. In the comparison of 7.5 g/L,3.75 g/L,1.875 g/L after the survival of the colony count and the initial colony number have significant difference. For the different propolis solution concentrations, on average, sterilization rate had significant difference.Sterilization rate of nearly 50% on 1.875 g/L propolis's solution, 3.75 g/L of sterilization rate reached more than 60% on average, an average of 7.5 g/L sterilization rate reached more than 90%.To sum up, the colony count and average sterilization rate were associated with propolis solution concentrations. The integrity of Porphyromonas gingivalis bacterium was damaged after inoculating with propolis solution.Conclusion The findings of the study suggested that propolis's solution has good inhibitory effect on Porphyromonas gingivalis and would be a useful approach for the treatment of peri-implantitis.

Key words: propolis, biofilms, chemical agents, titanium, peri-implantitis, Porphyromonas gingivalis