In vivo antimicrobial activity of an essential oil-containing mouthrinse on interproximal plaque bacteria

This study determined the in vivo interproximal bactericidal efficacy of an essential oil-containing antiseptic mouthrinse (Listerine Antiseptic) following toothbrushing. Thirty-four generally healthy adults, aged 23-64 years, completed this evaluator-blind, randomized, controlled, crossover designed study. Subjects rinsed for 30 seconds with 20 ml of either the essential oil rinse or a negative control rinse. Five minutes later, interproximal plaque was collected using paper points, and recoverable bacterial counts were quantified using both end point dilution and spectrophotometric methods. The results from the end point dilution demonstrated a statistically significant (p < 0.001) 43.8% reduction in recoverable plaque bacteria from interproximal spaces following rinsing with the essential oil mouthrinse. This study suggests that the clinical effectiveness of the essential oil mouthrinse against plaque and gingivitis may be attributable to the rapid kill and plaque permeabilizing properties of the formulation.