The effects of two essential oil mouthrinses on supragingival plaque regrowth: a comparative study

Aim: The aim of the study was to investigate the plaque inhibiting effects of two commercially available mouthrinses containing essential oils (EO): Listerine (Johnson & Johnson Consumer Healthcare, S. Palomba-Pomezia, I) and Curasept Daycare (Curaden Healthcare, Saronno, I). Both products contain the same concentration of EO, but Curasept Daycare does not contain ethanol as a solvent. Material and Methods: The study was a single-center, observermasked, cross-over design with 12 subjects randomly allocated to treatment sequence according to three replicates of a 4x4 Latin square, incorporating balance for any carryover. 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, which, in turn, was significantly more effective than the rinse without ethanol and the saline. The reduction in plaque regrowth seen with the EO rinse without ethanol was quite similar to that elicited by saline (P>0.05). Conclusion: The two EO-containing mouthrinses, although containing the same active ingredients, did not exert similar plaque inhibition. Moreover, the rinse without ethanol was found to inhibit plaque regrowth to the same extent than the saline solution (negative control). These findings suggest that the EO rinse without ethanol would provide poor plaque control benefits when used alongside toothbrushing.