The aim of this study was to examine the antibacterial effect of several current orthodontic materials against a certain oral bacterium. The antibacterial activities of six orthodontic composite resins (Transbond LR, Light Cure Retainer (LCR), Light Bond, System 1+, Kurasper F, Transbond XT adhesive), two orthodontic bonding materials (Transbond XT primer and System 1+ activator) and two glass ionomer cements (GIC) [Multicure Glass Ionomer and Ketac Cem GIC] were evaluated against Streptococcus mutans. The hard materials were put into the Teflon mould. The liquid materials were put on a paper disc. All materials were handled under aseptic conditions and placed on agar culture plates. All plates were incubated at 5% CO2 and 37 °C for 48 hours. The bacterial growth inhibition zones including the diameter of the sample were measured in millimetres. As a result of this study, the multicure GIC showed the highest antibacterial effectiveness, but no inhibition zones were noted for ketac cem GIC. The light bond adhesive of the Reliance orthodontic bonding system produced high antibacterial effect against S mutans, while the Reliance composite (LCR) did not show any antibacterial effect (p < 0.05). Both composite and primer of the transbond XT system demonstrated significant antibacterial effect against the test bacterium when compared to transbond LR (p < 0.05).
Among the materials tested, kurasper F, Ormco system 1+ and system 1+ activator showed slight or no inhibitory effect against the test bacterium in this study. In patients who have relatively high salivary levels of Streptococci mutans before treatment, the multicure GIC, the Reliance light bond adhesive, and transbond XT system which had high level antibacterial properties could be applied.