Comparison of safety, salivary flow rate, and pH with different mouthrinse formulations in addition to toothbrushing vs toothbrushing only: Results from a 2-week phase 4 randomized controlled clinical trial

Abstract

Background: Some mouthrinse ingredients are perceived as being associated with a reduction in salivary flow, leading to dry mouth. In this trial, the authors evaluated the effect of essential oil (EO)-containing mouthrinses, with or without alcohol, in addition to toothbrushing on oral soft- and hard-tissue tolerance through 14 days, and the impact on salivary flow and pH after a single use.

Methods: This was an examiner-blinded, randomized controlled clinical trial that enrolled 253 adults in good general and oral health. Participants were randomized 1:1:1:1:1 to toothbrushing only or toothbrushing and rinsing with 1 of 4 EO-containing mouthrinses. Oral soft- and hard-tissue tolerance and safety were assessed through 14 days; salivary flow and pH were evaluated after a single use at day 0.

Results: No unexpected adverse events were reported, and no new safety signals were identified. After a single use on day 0, participants in all mouthrinse groups had increased salivary flow levels compared with those in the toothbrushing only group through 30 minutes, with differences significant at 0 and 30 minutes after intervention (P < .05). Salivary pH remained in the neutral range for all mouthrinse groups through 30 minutes. Assessed outcomes for alcohol-containing and alcohol-free mouthrinses were similar.

Conclusions: The EO-containing mouthrinses in this trial were well tolerated with twice-daily use after manual toothbrushing and did not reduce salivary flow or lower salivary pH through 30 minutes after a single use; no adverse events of dry mouth were reported through 14 days.

Practical implications: The recommendation of adding EO-containing mouthrinses to twice-daily toothbrushing should be considered for controlling plaque and gingivitis effectively. This clinical trial was registered at ClinicalTrials.gov. The registration number is NCT05645705.

Keywords: Mouthrinse; dry mouth; essential oils; gingivitis; plaque; salivary flow; salivary pH; toothbrushing.