Effects of two essential oil mouthrinses on 4-day supragingival plaque regrowth: a randomized cross-over study.

Purpose: To investigate the plaque inhibiting effects of two commercially available mouthrinses containing essential oils (EO). Both products contained the same concentration of EO, but one of them did not contain ethanol.

Methods: The study was an observer-masked, randomized, 4 x 4 Latin square cross-over design, balanced for carryover effects, involving 12 participants in a 4-day plaque regrowth model. A 0.12% chlorhexidine (CHX) rinse and a saline solution served as positive and negative controls, respectively. On Day 1, subjects received professional prophylaxis, suspended oral hygiene measures, and commenced rinsing with their allocated rinses. On Day 5, subjects were scored for disclosed plaque.

Results: Differences among treatments were highly significant (P < 0.0001), with greater plaque inhibition by CHX compared to EO rinse containing ethanol (P = 0.012), which, in turn, was significantly more effective than the rinse without ethanol and the saline (P < 0.001). The reduction in plaque regrowth seen with the EO rinse without ethanol was quite similar to that elicited by saline (P > 0.05).