Changes in Salivary Flow and Oral pH Following Use of Different Mouthrinse Formulations in Addition to Brushing Versus Brushing Only.

<b>Purpose</b> Mouthrinses contain inactive ingredients (e.g., solvents, such as alcohol) and active ingredients (e.g., antimicrobials, such as essential oils [EOs]) that work in combination to control gingival inflammation and regulate the oral microbiome. The purpose of this one-day, examiner-blind, randomized, parallel-group-controlled clinical trial was to understand the effect of different EO-containing mouthrinses, with and without alcohol, on salivary flow and pH.<b>Methods</b> Subjects aged ≥18 years were recruited to participate in a one-day trial conducted at an independent research center. Salivary flow and pH were measured following a regimen of brushing and rinsing with an EO-containing mouthrinse versus brushing and rinsing with a water rinse control (BW). Eligible participants were assigned 1:1:1:1 to the BW group or one of three EO-containing mouthrinse groups. Change in salivary flow and pH after a single use of an EO-containing mouthrinse compared to the BW group was assessed at 0 (salivary flow only), then at 2.5, 5, 10, 15, and 30 minutes.<b>Results</b> A total of 159 subjects completed the clinical trial. At 30 minutes following the intervention, the mean salivary flow was similar across all groups. The mean salivary pH increased in all groups through 15 minutes before returning to near-baseline levels by 30 minutes (all of which were within the normal oral pH range of 6.2-7.6). No adverse events were reported.<b>Conclusion</b> The inclusion of alcohol in the tested mouthrinse formulations did not affect salivary flow or pH compared with the alcohol-free mouthrinses, indicating that a single use of either an alcohol-containing or alcohol-free EO-containing mouthrinse does not contribute to oral dryness. Future trials investigating the long-term use of mouthrinses and their effect on salivary flow and pH will help to build on the current evidence base and inform clinical decision-making.