Efficacy of two mouthwashes on 3-day supragingival plaque regrowth: a randomized crossover clinical trial

The aim of this study was to evaluate the antiplaque effects of an alcohol-free essential oil (alcohol-free EO) mouthwash and an amine fluoride/stannous fluoride with zinc lactate (SnFl-Zn) mouthwash compared to a positive control of chlorhexidine (CHX) mouthwash, using an in vivo plaque regrowth model of 3 days.

The study was designed as a double-masked, randomized, crossover clinical trial, involving 20 volunteers to compare two different mouthwashes, using a 3-day plaque accumulation model. After receiving thorough professional prophylaxis at baseline, over the next 3 days, each volunteer refrained from all oral hygiene measures and performed two daily rinses with 20 ml of the test mouthwashes. A 0.20% CHX rinse served as a positive control. At the end of each experimental period, plaque was assessed, and the panellists completed a questionnaire. Each subject underwent a 14-day washout period, and then, there was another allocation.

The SnFl-Zn mouthwash has shown a better inhibitory activity on plaque regrowth compared to the alcohol-free EO mouthwash in the whole mouth (plaque index = 1.93 against 2.45, respectively), but there was less of an effect compared to the CHX group, with an overall plaque index of 1.41. The differences of 0.52 between alcohol-free EO and SnFl-Zn and between SnFl-Zn and CHX and of 0.96 between alcohol-free EO and CHX were all statistically significant (P < 0.001).

The alcohol-free EO mouthwash seemed to have less of an inhibiting effect on plaque regrowth than the amine fluoride/SnFl-Zn mouthwash and the CHX control.