In Vitro Efficacy of Essential Oil Mouthrinse versus Dentifrices

Journal of Dentistry

Available online 31 August 2017

In Press, Accepted Manuscript

Abstract

Objectives

To compare the antimicrobial efficacy and kill penetration of essential oils (EO) mouthrinse versus stannous fluoride, and triclosan dentifrice slurries on saliva-derived biofilms using confocal laser scanning microscopy (CLSM).

Methods

Saliva-derived biofilms were grown for 48 hours on hydroxyapatite discs using pooled, homogenized saliva from 8 healthy volunteers as the inoculum. The mean thickness of these biofilms was 84 μm (range, 23–241 μm). CLSM with viability mapping was used to visualize the antimicrobial kill penetration of each treatment regime within a biofilm.

Results

At 30 s treatment durations, CLSM imaging revealed greater antimicrobial activity and kill penetration of EO mouthrinse compared to sodium fluoride-, stannous fluoride-, and triclosan-containing dentifrice slurries. Quantification of biovolume revealed that EO mouthrinse treatment at 30 s resulted in a greater non-viable biovolume proportion (84.6% ± 15.0%) than other treatment groups. Increasing the treatment duration of the triclosan dentifrice (to 60 and 120 s) resulted in better penetration and an increased reduction of viable cells, comparable to EO mouthrinse treatment at 30 s duration. Further, CLSM imaging showed that the combined treatment of a non-antimicrobial dentifrice (45 s) with EO mouthrinse (30 s) showed superior antimicrobial activity (96.2% ± 3.7%) compared to the antimicrobial triclosan-containing dentifrice used without a mouthrinse step (26.0% ± 32.0%).

Conclusions

Within typical exposure times, the EO-containing mouthrinse can penetrate deep into the accumulating plaque biofilm compared to the chemotherapeutic dentifrice slurries, and may provide an efficacious alternative to triclosan, when used as an adjunct with a mechanical oral care regimen.

Clinical Significance

Using viability mapping and CLSM, this study demonstrated that EO-containing mouthrinse penetrates and kills microorganisms deeper and more effectively in plaque biofilm in typical exposure times when compared to dentifrice chemotherapeutic agents, providing an efficacious alternative to triclosan or stannous fluoride when used as an adjunct to mechanical oral care.