Antibacterial and mechanical properties of ceramic orthodontic brackets with nano silver hydroxyapatite coating

Zhou Guan-jun; Yang Da-peng; Liu Xin-fang; Hu Bo

doi:10.3969/j.issn.2095-4344.2015.52.011

Abstract：BACKGROUND:In the clinical orthodontics, ceramic brackets have deficiencies in the aspects of antibacterial and mechanical properties, which easily lead to the emergence of a variety of adverse events and influence the orthodontic effect. OBJECTIVE:To observe the antibacterial and mechanical properties of nano silver hydroxyapatite coating ceramic brackets. METHODS:The nano silver hydroxyapatite coating ceramic brackets were prepared. Scanning electron microscopy was used to observe the coating surface. Coating antibacterial experiment was conducted. Totaly 50 in vitro human maxilary premolars were randomly divided into two groups (n=25 per group): experimental and control groups. Premolars in the experimental group were bonded to nano silver coating hydroxyapatite ceramic brackets, and premolars in the control group were bonded to ordinary ceramic brackets. The shear strength was detected in these two groups.RESULTS AND CONCLUSION: The overall structure of nano silver hydroxyapatite coating was order, uniform and compact. Hydroxyapatite had a porous structure with a micro-nanometer aperture and there were a large number of nano-silver particles uniformly distributed. Quantitative antibacterial experiments showed that nano silver hydroxyapatite coating ceramic brackets had a strong inhibition to Escherichia coli and Staphylococcus albus, with an antibacterial rate of more than 95%. The shear strength in the experimental group was lower than that of the control group (P < 0.05). These results demonstrate that the nano silver hydroxyapatite coating ceramic brackets have good antibacterial and mechanical properties, which meet the requirement of mechanical change in the clinical orthodontics.