From the evidence for adjunctive antibacterial mouthrinse to what really happens when patients rinse after brushing, some familiar assumptions about mouthwash deserve a closer look.
Mouthwash recommendations can sometimes become reduced to simple rules: mechanical cleaning should be enough, or rinsing after brushing will wash fluoride away. However, the evidence presents a more nuanced picture, with different formulations offering different potential benefits according to individual patient need. As dental professionals look to personalise self-care advice, two common assumptions are worth revisiting.
Myth: there is no evidence for adjunctive antibacterial mouthrinse
Effective mechanical plaque control remains fundamental to oral hygiene, but current periodontal guidance also recognises a role for adjunctive antiseptic agents. The UK implementation of the European Federation of Periodontology (EFP) S3-level guideline advises that, where mechanical procedures alone do not effectively control supragingival biofilm and/or gingival inflammation, consideration can be given to a toothpaste and/or mouthrinse containing a specific active agent (West et al, 2021).
The guidance reflects a substantial evidence base, including a systematic review and meta-analysis of six-month randomised controlled trials that included 70 studies of adjunctive antiseptics. This found statistically significant additional reductions in gingival index, bleeding and plaque measures compared with mechanical plaque control alone. When individual agents were assessed, essential oils used alongside mechanical plaque control demonstrated statistically significant additional reductions in plaque indices compared with mechanical plaque control alone (Figuero et al, 2020).
The EFP S3-level guideline also evaluated evidence for 11 different mouthrinse formulations during supportive periodontal care. Essential oil (EO) and chlorhexidine mouthrinses were ranked among the most efficacious agents for changes in plaque and gingival indices, although the guideline emphasises that the choice of an adjunct should form part of a personalised approach (West et al, 2021).
For plaque management specifically, a meta-analysis of 29 six-month clinical trials provides further evidence for the fixed combination of four essential oils used in LISTERINE. At six months, 36.9% of participants using mechanical methods plus the EO-containing mouthrinse achieved at least 50% plaque-free sites, compared with 5.5% using mechanical methods alone (Araujo et al, 2015).
The evidence therefore supports considering an adjunctive antibacterial mouthrinse in specific circumstances, alongside effective mechanical plaque control and according to individual patient need.
Myth: rinsing after brushing washes fluoride away
The familiar advice to ‘spit, don’t rinse’ has an important qualification. The Delivering Better Oral Health toolkit (2025) advises patients to spit after brushing rather than rinse with water, to avoid diluting the fluoride.
A fluoride-containing mouthwash is different. In a randomised crossover study, participants brushed with 1,450 ppm fluoride toothpaste before either rinsing with a mouthwash containing 225 ppm fluoride, rinsing with one containing 500 ppm fluoride or not rinsing at all (Sköld et al, 2012).
Both fluoride mouthwashes significantly increased salivary fluoride retention over the following 60 minutes compared with not rinsing after brushing with 1,450 ppm fluoride toothpaste (Sköld et al, 2012).
The key distinction is what patients rinse with: water can dilute fluoride after brushing, while for patients who would benefit from additional fluoride, a mouthwash containing at least 225 ppm fluoride may increase post-brushing salivary fluoride retention (Sköld et al, 2012).
Where plaque control remains suboptimal, LISTERINE, with its evidence-based fixed combination of four essential oils, may in specific circumstances provide additional antibacterial support alongside mechanical plaque control (Araujo et al, 2015; Figuero et al, 2020; West et al, 2021).
References
- Araujo MWB, Charles CA, Weinstein RB, et al (2015) Meta-analysis of the effect of an essential oil-containing mouthrinse on gingivitis and plaque. Journal of the American Dental Association; 146(8): 610–622.
- Delivering Better Oral Health: an evidence-based toolkit for prevention (2025) Office for Health Improvement and Disparities, Department of Health and Social Care, NHS England and NHS Improvement. Chapter 2: Summary guidance tables for dental teams.
- Figuero E, Roldán S, Serrano J, et al (2020) Efficacy of adjunctive therapies in patients with gingival inflammation: a systematic review and meta-analysis. Journal of Clinical Periodontology; 47: 125–143.
- Sköld UM, Birkhed D, Ellwood R (2012) Effect of post-brushing mouthwash solutions on salivary fluoride retention – study 1. Journal of Clinical Dentistry; 23(3): 97–100.
- West N, Chapple I, Claydon N, et al (2021) BSP implementation of European S3-level evidence-based treatment guidelines for stage I–III periodontitis in UK clinical practice. Journal of Dentistry; 106: 103562.
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This article is sponsored by LISTERINE.
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