After using the macrodilution test it was observed a significant reduction in the number of cells of S. mutans after 4 h of contact with the antimicrobial films. A count of 1.6 × 103 CFU mL−1 was obtained after treatment with E. globulus films and 1.1 × 105 CFU mL−1 after contact with E. urograndis films. Compared with the film prepared without the addition of essential oil, the addition of EOs did not affect the structure of the films but became opaque, which may be an undesirable feature when developing bioactive packaging that allows for visualization of the product. However, this feature may be desirable to prevent the passage of light to decrease the risk of oxidation.