OBJECTIVE Manufacturers commonly provide information on the physical properties of dental materials, but information on their antibacterial properties is often missing. This study determined the antibacterial properties of four currently used orthodontic band cements against three different strains of Streptococcus mutans. METHODS The cements utilized were Durelon, Ketac, Mizzy Zinc Phosphate, and Band-Lok, a recently introduced, resin-based, dual-cure glass ionomer cement. Disk diffusion assay methodology was used to test for zones of bacterial inhibition around cement samples. Zones of inhibition were measured in millimeters using an electronic caliper. In addition to cured cement plugs and freshly mixed cement samples, a new variation, in the form of a cement plug surrounding a stainless-steel band, was tested. Twelve combinations resulted from the four cement types and three forms. RESULTS Of the variables studied, the mix forms of Durelon, Ketac, and Mizzy Zinc Phosphate cement showed the greatest bacterial inhibition (Kruskal-Wallis, P < 0.05). Among the cements tested, Mizzy Zinc Phosphate showed the largest zones of inhibition, with Durelon and Ketac having comparable zones of inhibition (Kruskal-Wallis, P < 0.05). Band-Lok did not exhibit an inhibitory effect against any of the three strains of S. mutans tested. CONCLUSIONS A "containment effect" of no bacterial inhibition was observed in the cement samples surrounded by the stainless-steel band material.