Choosing the right mouthwash

Choosing the right mouthwash

This article presents an overview of the latest evidence regarding the efficacy of a variety of mouthwash formulations

This article is equivalent to one hour of Enhanced CPD

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Learning Outcomes: A | C | D

Aims & Objectives

The aim of this article is present an overview of the latest evidence regarding the efficacy of a variety of mouthwash formulations, to help dental health care professionals guide patients in choosing which might be the most effective to meet individual needs.

On completing this Enhanced CPD session, the reader will:

  1. Understand the situations in which recommending a mouthwash as an adjunct to brushing and interdental cleaning may be appropriate
  2. Understand the efficacy of a variety of the widely available active ingredients
  3. Understand why alcohol-free mouthwash may offer a desirable alternative
  4. Understand the effectiveness of alcohol-free versus alcohol-containing essential oil mouthwash, as an adjunct to mechanical cleaning

This article explores the current situation regarding antibiotic use in dentistry and antimicrobial resistance

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The first documented mouthwash preparation was around 2700 BCE, using a child’s urine. Over the intervening years, a variety of ‘active’ ingredients have been used, ranging from Pliny’s salt water to Hippocrates’ preference for a mixture of salt, alum and vinegar.1

Over time, science has enabled the creation of more palatable and evidence-based formulations, including Joseph Lawrence and Jordan Wheat Lambert’s combination of four essential oils – thymol, menthol, eucalyptol and methyl salicylate1 – as well as chlorhexidine, cetylpyridinium, triclosan and delmopinol, to name just a few of those most widely available.2

Why recommend mouthwash?

Time, effort and money have been spent creating mouthwash, but why would that be when we know that it is ‘…. possible to maintain a level of oral hygiene […] using mechanical methods alone’? The truth is that data indicates this is not enough for majority of people to maintain an acceptable level of oral health.3

The Adult Dental Health Survey 2009, for example, indicated that two-thirds of dentate adults had visible plaque on at least one tooth, despite three-quarters of participants claiming to brush their teeth at least twice a day, and a quarter of those also cleaning interdentally.4

Working Group 2 of the 11th European Workshop in Periodontology considered this shortfall, stating that two minutes of toothbrushing is likely to be insufficient for periodontitis patients. It was further put forward that, for patients with gingivitis, the addition of once-daily interdental cleaning and the adjunctive use of a chemical plaque control agent would help in the recovery of oral health. In overview, it was suggested that for some patients there are advantages to the adjunctive use of chemical agents for plaque control.5

Which formulation?

Boyle and colleagues (2014) considered the efficacy of a number of the more widely available mouthwash formulations. Chlorhexidine, for example, when used for fewer than three months, was found to be the most effective of the mouthwash variants investigated (specifically, chlorhexidine, essential oils, cetylpyridinium, triclosan and delmopinol).2

Based on these findings, Boyle and colleagues (2014) wrote: ‘An adjunctive method of plaque control is the use of antiseptics, of which chlorhexidine is the most effective [in studies of less than three months] although its tendency to stain teeth and impair taste makes it generally unacceptable for long-term use.’2

When the efficacy of the five formulations was reviewed over a six-month-plus period, Boyle and colleagues (2014) deduced that essential oil-containing mouthwash equalled or exceeded the effect of chlorhexidine in controlling plaque as an adjunct to standard care.2

As for the remaining three active ingredients investigated: ‘‘Mouthwash preparations containing cetylpyridinium or triclosan may […] be effective, but less than the two former [chlorhexidine and essential oils], while mouthwashes containing delmopinol are not effective for plaque and gingivitis control.’2

If we accept that over the longer term (six months or longer) an essential oil mouthwash may be the formulation of choice, as it equals the efficacy of chlorhexidine but without the possibility of staining teeth or affecting taste, it is worth looking at Araujo and colleagues’ (2015) meta-analysis. This was the first meta-analysis using responder analysis over a six-month period to demonstrate a clinically significant, site-specific benefit of a mouthwash containing essential oils on plaque levels.6

Having reviewed the data, Araujo and colleagues (2015) wrote that the: ‘Addition of daily rinsing with an EO [essential oil] mouthwash to mechanical oral hygiene provided statistically significantly greater odds of having a cleaner […] mouth, which may lead to prevention of disease progression.’6

Avoiding alcohol

For some patients, the addition of alcohol in mouthwash has limited their use, for example for religious reasons, for alcoholics, and for those with oral mucositis.7

Whilst the effectiveness of essential oil mouthwash has been researched quite extensively over the years, it is only recently that the first study to compare the anti-plaque efficacy of alcohol-containing and alcohol-free variants was published.7

To ascertain whether choosing an alcohol-free essential oil mouthwash variant affected efficacy, Lynch and colleagues (2018) divided their randomised, controlled, examiner-blind, parallel-group study participants into three cohorts:

  1. Mechanical cleaning only (MOH)
  2. Mechanical cleaning plus alcohol-containing essential oil mouthwash (ACM)
  3. Mechanical cleaning plus alcohol-free essential oil mouthwash (AFM).7


It was found: ‘The results of the current study show that both the AFM and ACM provide a statistically and clinically significant additional benefit in subjects who performed their daily MOH. After one month, use of either the AFM or ACM showed significant reduction in plaque (21.4% and 20.6%, respectively) […] compared to MOH alone. By month six, further reduction in plaque was noted; up to 37.0% and 37.8% in the AFM and ACM groups, respectively […].’7

In conclusion, over a six-month period, ‘No significant differences were observed in the efficacy of ACM and AFM to reduce plaque […], when used in addition to MOH’.7

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Discussing suitability

Ultimately, it is for the dental professional and patient to discuss what may be best for their individual needs.

The British Dental Association states: ‘Systematic reviews of the efficacy and outcomes of mouthwash use indicate that certain mouthwashes provide additional benefit with regard to plaque and associated dental diseases when used in addition to brushing and interdental oral hygiene aids and techniques, under professional guidance. ‘

‘Patients should discuss with their dentist which mouthwashes are suitable for use as part of their oral hygiene cleaning measures.’

‘Alcohol-containing mouthwashes may pose ethical and cultural issues for some population and age groups.’

‘In all case mouthwashes should be used according to manufacturer's directions to minimise possible side effects on, for example, certain forms of tooth-coloured restorations.’8



  1. Fischman SL. The history of oral hygiene products: how far have we come in 6000 years? Periodontology 2000 1997; 15: 7-14

  2. Boyle P et al. Mouthwash use and the prevention of plaque, gingivitis and caries. Head and Neck Oral Diseases 2014; 20 (Supp1): 1-68

  3. Barnett ML. The rationale for the daily use of an antimicrobial mouthrinse. JADA 2006; 137: 16S-21S

  4. The Adult Dental Health Survey 2009. The Health and Social Care Information Centre 2011

  5. Chapple ILC et al. Primary prevention of periodontitis: managing gingivitis. Clin Periodontol 2015; 42 (Suppl. 16): S71-S76

  6. Araujo MWB et al. Meta-analysis of the effect of an essential oil-containing mouthrinse on gingivitis and plaque. JADA 2015; 146(8): 610-622

  7. Lynch MC et al. The effects of essential oil mouthrinses with or without alcohol on plaque and gingivitis: a randomized controlled clinical study. BMC Oral Health 2018 10; 18(1): 6

  8. Accessed 17 May 2018