Quantitative analysis of the effects of essential oil mouthrinses on clinical plaque microbiome: a parallel-group, randomized trial.

BACKGROUND: The rich diversity of microorganisms in the oral cavity plays an important role in the maintenance of oral health and development of detrimental oral health conditions. Beyond commonly used qualitative microbiome metrics, such as relative proportions or diversity, both the species-level identification and quantification of bacteria are key to understanding clinical disease associations. This study reports the first-time application of an absolute quantitative microbiome analysis using spiked DNA standards and shotgun metagenome sequencing to assess the efficacy and safety of product intervention on dental plaque microbiome. METHODS: In this parallel-group, randomized clinical trial, essential oil mouthrinses, including LISTERINE® Cool Mint Antiseptic (LCM), an alcohol-containing prototype mouthrinse (ACPM), and an alcohol-free prototype mouthrinse (AFPM), were compared against a hydroalcohol control rinse on clinical parameters and the oral microbiome of subjects with moderate gingivitis. To enable a sensitive and clinically meaningful measure of bacterial abundances, species were categorized according to their associations with oral conditions based on published literature and quantified using known amounts of spiked DNA standards. RESULTS: Multivariate analysis showed that both LCM and ACPM shifted the dysbiotic microbiome composition of subjects with gingivitis to a healthier state after 4 weeks of twice-daily use, resembling the composition of subjects with clinically healthy oral conditions recruited for observational reference comparison at baseline. The essential oil-containing mouthrinses evaluated in this study showed statistically significant reductions in clinical gingivitis and plaque measurements when compared to the hydroalcohol control rinse after 6 weeks of use. CONCLUSIONS: By establishing a novel quantitative method for microbiome analysis, this study sheds light on the mechanisms of LCM mouthrinse efficacy on oral microbial ecology, demonstrating that repeated usage non-selectively resets a gingivitis-like oral microbiome toward that of a healthy oral cavity. TRIAL REGISTRATION: The trial was registered on ClinicalTrials.gov on 10/06/2021. The registration number is NCT04921371.

Comparative Effectiveness of Toothbrushing, Flossing and Mouthrinse Regimens on Plaque and Gingivitis: A 12-week virtually supervised clinical trial.

Purpose:Various mechanical and chemotherapeutic methods are used to control dental plaque accumulation and prevent or reduce gingivitis. The purpose of this 12-week clinical trial was to investigate the effects of various combinations of supervised mechanical and chemotherapeutic regimens on the prevention and reduction of plaque, gingivitis, and gingival bleeding.Methods:Volunteers presenting with some evidence of gingivitis and no severe periodontitis were randomized into four groups: brush only (BO); brush/rinse (BR); brush/floss (BF); brush/floss/rinse (BFR) for this examiner-blinded clinical trial. Toothbrush, toothpaste, floss and a mouthrinse containing a fixed combination of four essential oils (EO) and training/instructions were provided to participants as per their assigned group. Participants performed their regimen at home, under virtual supervision, once each weekday; the second daily and weekend uses were unsupervised. Assessments included oral hard and soft tissue, plaque, gingivitis, and gingival bleeding (weeks 4, 12); probing depth and bleeding on probing (week 12).Results:Of 213 enrolled participants, 209 completed the study. After 12 weeks, plaque, gingivitis, and gingival bleeding were significantly reduced in groups BR (35.8%, 50.8%, and 71.0% respectively, p<0.001) and BFR (32.8%, 54.1%, and 78.2% respectively, p<0.001) compared to BO. After 12 weeks, gingivitis and gingival bleeding were significantly reduced in the BF group (9.2%, p=0.013 and 17.5%, p=0.003, respectively), however there were no significant reductions in plaque in the BF group as compared to the BO group (p=0.935).Conclusions:Oral care regimens that included a mouthrinse containing a fixed combination of four EOs (BR and BFR), demonstrated statistically significantly reduced plaque, gingivitis, and gingival bleeding as compared to BO and BF after 12 weeks. The BF regimen statistically significantly reduced gingivitis and gingival bleeding but did not statistically significantly reduce plaque compared to BO after 12 weeks.