Figure 2.

Effect of Chrysanthemum boreale (C. boreale) essential oil on colony-forming units (CFU) of Streptococcus mutans (S. mutans). S. mutans was inoculated into BHI broth with various concentrations of C. boreale essential oil and incubated for 24 h. The CFU of S. mutans that adhered to saliva-coated hydroxyapatite beads that were treated with various concentration of C. boreale essential oil are shown. When treated with 0.1–0.5 mg/mL of C. boreale essential oil, adherence was significantly repressed. Each value is expressed as a mean ± standard deviation (SD). Significance was determined at ^* P < 0.05 when compared with the control. 0.1% of sodium fluoride (NaF) was used as a positive control.