Fig. 1

Antibacterial activity of OEOs. Parallel reactions to which no drug was added were used as controls. A Antibacterial activities of OEOs. B Effect of OEOs on acid production. The pH values of the all samples were all 7.01 as indicated by the dark columns, which represented the pH values of each sample prior to inoculation (0 h). Following inoculation and a 24-h culture period, the pH values of each sample were represented by the light-colored columns. C Effect of OEOs with various concentrations on hydrophobicity of S. mutans. D Inhibitory effect of OEOs on biofilm formation of S. mutans. The biofilm mass can be determined by dissolving crystal violet attached to the biofilm. E Effect of OEOs on biofilm formation on polystyrene dishes by S. mutans. The red-stained parts represented the deposited biofilm. Equal letters represent no differences while different ones represent significant differences (p < 0.05)