Effect of eucalyptus-extract chewing gum on oral malodor: a double-masked, randomized trial

Eucalyptus extracts were found to possess an antibacterial activity against some oral pathogens that produce oral malodor compounds in vitro; however, the clinical effects with respect to oral malodor in humans remain unproven. In the present investigation, a randomized clinical study was designed to test the hypothesis that eucalyptus-extract chewing gum can reduce oral malodor in the general adult population.

Subjects were randomly assigned to the following three groups: a high-concentration (0.6% eucalyptus extract) group (n = 32), a low-concentration (0.4% eucalyptus extract) group (n = 32), and a placebo group (n = 33). The intake period was 12 weeks. The organoleptic score, level of volatile sulfur compounds (VSCs), and tongue-coating score were recorded at baseline and 4, 8, 12, and 14 weeks. Treatment-to-time interactions among groups were evaluated by repeated-measures analysis of variance (ANOVA) followed by the Games-Howell pairwise comparison test.

Relative to baseline readings, significant reductions in clinical parameters, including organoleptic and tongue-coating scores in the high- and/or low-concentration groups, occurred at 4, 8, 12, and 14 weeks (P <0.05). In addition, group-time interactions revealed significant reductions in the organoleptic score, VSCs, and tongue-coating score in both concentration groups compared to the placebo group (P <0.05).

Eucalyptus-extract chewing gum had long-term effects on the olganoleptic score, levels of VSCs, and tongue-coating score. These findings suggest that eucalyptus-extract chewing gum may reduce oral malodor by decreasing the accumulation of tongue coating.