Antibacterial effect of various glass ionomers

Objectives: Several studies have demonstrated the antibacterial effect of glass ionomers (GIs) on the major pathogens causing dental caries. These antibacterial properties of GIs have been attributed to both the high concentrations of fluoride and to the low pH of these materials. The purpose of this in-vitro study was to examine the inhibiting effect of several GI restorative materials on bacterial growth. Methods:Using the agar diffusion test antibacterial activities of 4 GIs, Fuji IX (F9, auto-cure:AC), Fuji II LC (F2, light-cure), PhotacFil Quick (PF, LC) and one experimental GI (EXPA in AC and EXPL in LC mode) were evaluated against the cariogenic S. mutans (clinical isolate) and S. sobrinus 6715. 1% Glutaraldehyde was used as control. The bacteria were grown in BHI broth or agar at 37 degrees under anaerobic conditions. Overnight broth cultures were concentrated 10x, and 0.1ml was spread over the surface of each agar plate. Wells of 6mm in diameter were punched and filled with material plugs, prepared according to manufacturer's recommendations. After 24 hours incubation the inhibition zone was measured. Results: The greatest inhibitory area (mm diameter/SD) was produced by the control(11.65/0.77) followed by EXPA (9.28/0.68) and F9(9.07/0.62), EXPL(8.08/0.52), F2 (7.24/0.29) and PF(7.03/0.02). Conclusion: The AC materials showed greater inhibition than the LC materials. When compared to F2 and PF, both EXPA and F9 showed a significantly larger inhibitory effect against S. mutans and S. sobrinus.