Viability of established cultures, as determined using viable counts, following exposure to test rinses. Pelleted cultures of Streptococcus mutans (upper panel) and mixed salivary bacteria (lower panel) were exposed to mouthrinse formulations (final concentration, 100 %) containing CPC (TR) or CPC and fluoride (TFR) in triplicate. Control rinses without CPC (CR and CFR, respectively) and a treatment-free control (NTC) were also included. Data show bacterial viability, as determined by viable counts. Both test rinses caused significant reductions in viability compared to their respective controls in three separate experiments (*, p < 0.05, n = 3).