Effect of silver ion coating of fixed orthodontic retainers on the growth of oral pathogenic bacteria.

Titanium and stainless steel wires used for retainers in orthodontic procedures were coated with Ag ions and the effects of the coating on common oral pathogens and their pathogenicity were investigated. Two species of cariogenic and three species of periodontopathic bacteria were assessed. Biofilms of Streptococcus sobrinus and two VSC gases produced by P. gingivalis were also examined. Ag ion-coated wires showed marked antibacterial activities compared with uncoated wires; in most cases, the differences were statistically significant (p<0.05). All Ag ion-coated wires (Ti+ and SS+ wires) displayed more than 2-mm diameter bacteria growth-resistant zones around them in radial diffusion tests. Ag ion release was 0.043±0.005 ppm in 24 h that didn't show cytotoxicity. Thus, these results suggest that a simple Ag ion coating on pure titanium and stainless steel wires can restrict growth and pathogenic activities of oral pathogenic bacteria, even in the early stages of culture.