Antimicrobial effectiveness of an herbal mouthrinse compared with an essential oil and a chlorhexidine mouthrinse

BACKGROUND: The authors investigated mouthrinses' antimicrobial effectiveness against predominant oral bacteria, as determined by the minimum inhibitory concentration (MIC). Specifically, they evaluated an herbal mouthrinse, an essential oil rinse and a 0.12 percent chlorhexidine gluconate rinse. METHODS: The authors assessed the inhibitory effects of the three test agents against 40 oral bacteria at concentrations of 1, 2, 4, 8, 16, 32, 64, 128, 256 and 512 micrograms per millliter. They inoculated plates containing basal medium and the test agents with suspensions of the test species and incubated them anaerobically at 35 degrees C. The authors interpreted the MIC as the lowest concentration of the agent that completely inhibited the growth of the test species. RESULTS: The herbal mouthrinse inhibited the growth of most of the 40 test species. Compared with the essential oil mouthrinse, the herbal mouthrinse exhibited significantly lower MICs for Actinomyces species, periodontal pathogens Eubacterium nodatum, Tannerella forsythia and Prevotella species, as well as the cariogenic pathogen Streptococcus mutans. The chlorhexidine gluconate rinse had the lowest MICs compared with the essential oil rinse and the herbal rinse for all test species examined. CONCLUSIONS: Although less potent than the chlorhexidine gluconate rinse, the herbal rinse was more effective than the essential oil rinse in inhibiting the growth of oral bacteria in vitro. CLINICAL IMPLICATIONS: The data suggest that the herbal mouthrinse may provide oral health benefits by inhibiting the growth of periodontal and cariogenic pathogens. In vivo clinical testing is essential to confirm in vitro results.