The effect of antibacterial mouthwash on blood pressure in humans: a scoping review

Abstract Background Oral hygiene is a key component of health. Practices for oral hygiene include brushing teeth with toothpaste, flossing, and mouth washing. It has been reported that 36% of United States adults use mouthwash daily. However, antibacterial mouthwashes kill oral nitrate-reducing bacteria, thus impairing nitric oxide production. Nitric oxide is a key molecule in vasodilation and blood pressure regulation, often acting as a mediator, so there is a potential for antibacterial mouthwashes to cause elevated blood pressure. Therefore, we conducted a scoping review to address the question: Does antibacterial mouthwash use significantly increase blood pressure in humans? Methods A scoping review was conducted utilizing the databases PubMed and Scopus. Our search terms included “mouthwash,” “chlorhexidine,” “antibacterial,” “salivary nitrite,” “nitrate,” and MeSH terms like “blood pressure” and “hypertension.” Inclusion criteria required primary research articles since 2014 that analyzed changes in blood pressure in human adults after using antibacterial mouthwash. Studies with pediatric participants, animal studies, reviews, or studies that did not measure blood pressure changes were excluded. 51 studies were retrieved from the search, and after independent screening by two reviewers, nine studies were included in the scoping review. Reviewers extracted data on study methodology, sample size, participant characteristics, type of mouthwash, mouthwash regimen, and study results. Reviewers also appraised study quality using a modified Downs and Black assessment checklist. Results Nine studies were included: four randomized crossover trials, three nonrandomized crossover trials, one active-controlled trial, and one observational study. The studies were of good quality (mean modified Downs and Black score was 21.9 ± 2.9 out of 28 points). Five studies found significant blood pressure elevations after mouthwash usage, while four studies found no significant relationship. Conclusions Heterogeneity in intervention lengths, mouthwash composition, participant characteristics, and blood-pressure assessment schedules, in addition to methodological weaknesses (such as inadequate washout periods and lack of randomization) in some studies make the pooled evidence inconclusive. Consequently, no firm conclusions can be drawn regarding the effect of antibacterial mouthwash on blood pressure at this time. Future research should utilize larger, randomized trials with standard washout periods and long-term monitoring to further clarify the relationship between antibacterial mouthwash usage and blood pressure.