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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.

In people with mild gum disease chlorhexidine mouthwash, in addition to tooth brushing, reduces plaque build-up in the first weeks or months of use. However, when used for longer than four weeks chlorhexidine mouthwash can lead to tooth staining and a build-up of chalky deposits on the teeth, called tartar. There is insufficient evidence to assess its effectiveness in people with moderate to severe gum disease.

Plaque is a sticky bacteria-filled substance that forms on teeth and can cause gum disease, resulting in sore, bleeding gums, infections and even tooth loss. Chlorhexidine is an antiseptic which kills most bacteria. In the UK chlorhexidine mouthwashes are licensed for 30 days’ use and are not recommended for routine use.

This systematic review suggests that chlorhexidine mouthwash may be considered as an addition to usual care for people with mild gum disease. There is scope for further investigation of the role of chlorhexidine in moderate to severe gum disease.

Why was this study needed?

Dental plaque is a sticky substance containing bacteria that builds up where the teeth meet the gums. Some of the bacteria in plaque can be harmful to teeth and gums, leading to gum disease (gingivitis).

The symptoms of gum disease are sore and swollen gums that can bleed during tooth brushing or flossing, and bad breath. Untreated gum disease can lead to receding gums and gum abscesses, potentially causing loose teeth or even tooth loss. The easiest way to prevent gum disease is to maintain good oral hygiene through regular tooth brushing, flossing and regular dental check-ups.

Chlorhexidine is an antiseptic used in a variety of ways, including disinfecting skin before operations and cleaning wounds. This review explored whether chlorhexidine reduced gum disease, prevented plaque or slowed development of tartar (chalky deposits on the teeth).

What did this study do?

This Cochrane systematic review included 51 randomised controlled trials, including 5,345 people. The studies involved people brushing their teeth, either with or without using floss or other interdental brushes to clean between teeth, and professional tooth cleaning. To this dental hygiene regime was added chlorhexidine mouthwash, a placebo mouthwash or no mouth rinsing.

Fifty out of 51 studies were judged to be at high risk of bias; the other study had an unclear risk of bias. The main source of bias was around not concealing which treatment people received from them and those assessing their gum disease. There were high drop-out rates from studies, a risk of selective reporting and substantial differences between the studies. Despite these risks of bias, the authors feel that the consistency of results mean that we can have confidence in their findings.

What did it find?

  • Chlorhexidine mouthwash reduced mild gum disease (less than 1 on a gum disease scale of 0 to 3) by an average of ‑0.21 after four to six weeks (95% confidence interval [CI] ‑0.31 to ‑0.11) and by ‑0.20 after six months (95% CI ‑0.30 to ‑0.11). There was insufficient evidence to draw conclusions about the effectiveness of chlorhexidine in people with moderate to severe gum disease (scoring 1.1 to 3).
  • Using chlorhexidine moderately reduced gum bleeding at four to six weeks (standardised mean difference [SMD] ‑0.56, 95% CI ‑0.79 to ‑0.33) and six months (SMD ‑0.72, 95% CI ‑1.02 to ‑0.42).
  • Plaque was assessed using various tools including the Plaque Index and the Turesky modification of the Quigley Hein Index. All indicated that chlorhexidine use had a large effect in reducing plaque at four to six weeks (SMD ‑1.45, 95% CI ‑1.90 to ‑1.00) and at six months (SMD ‑1.59, 95% CI ‑1.89 to ‑1.29).
  • Levels of tartar were higher amongst people using chlorhexidine. Tooth staining was also significantly increased among people using chlorhexidine at four to six weeks, seven to 12 weeks and six months.
  • There was insufficient data to draw conclusions about whether the frequency or concentration of chlorhexidine affected any of the studied outcomes.

What does current guidance say on this issue?

NICE’s Clinical Knowledge Summary service recommends that tooth brushing and interdental cleaning are used to remove plaque. Mouthwashes are not recommended for routine gum disease treatment because they do not act on established plaque and do not stop gum disease from progressing. The British Society of Periodontology and the Scottish Dental Clinical Effectiveness Programme suggest that chlorhexidine mouthwashes may be helpful to control plaque in the short term when mechanical cleaning is painful. In the UK, chlorhexidine mouthwashes are only licensed for 30 days’ use.

What are the implications?

Combining tooth brushing and cleaning with chlorhexidine mouthwashes reduces plaque build-up, compared to tooth brushing and cleaning alone.

However, using chlorhexidine mouthwashes for longer than four weeks leads to tooth staining (requiring professional cleaning) and a build-up of tartar. This supports UK guidance and licensing, which already restricts chlorhexidine mouthwash use to 30 days at a time.

Healthcare professionals should discuss the likely benefits, limitations and risks of using chlorhexidine mouthwashes in addition to tooth brushing and cleaning in people with mild gum disease. They should also point out that they do not replace flossing and regular dental hygienist visits for tartar removal.

Citation and Funding

James P, Worthington HV, Parnell C et al. Chlorhexidine mouthrinse as an adjunctive treatment for gingival health. Cochrane Database Syst Rev. 2017;3:CD008676.

Cochrane UK and the Oral Health Cochrane Review Group are supported by NIHR infrastructure funding. The review was also funded by the Cochrane Oral Health Global Alliance and Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, UK.


BSP. The good practitioner’s guide to periodontology. London: British Society of Periodontology; 2016.

CKS. Scenario: gingivitis and periodontitis. London: National Institute for Health and Care Excellence; updated 2016.

NHS Choices. Gum disease. London: Department of Health; updated 2016.

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