Mouthwash: more harm than good?

Sir, we read with great interest the article titled 'Mouthwash use and risk of diabetes'1 in the November 2018 issue of the BDJ. The contents of mouthwash coupled with common habits surrounding the use of mouthwash could potentially have consequences on the oral as well as general health of our patients.

We have come across many patients who use mouthwash straight after brushing their teeth. This is a problem because a lot of mouthwashes have a fluoride content of 450 ppm whereas toothpaste contains 1450 ppm.

Using mouthwash straight after brushing reduces the fluoride concentration around the teeth, subsequently reducing the overall benefit of using toothpaste. Some patients, especially children, may be more likely to substitute toothpaste with mouthwash as this is less time consuming and requires less effort.

Additionally, in vitro and in situ research has found that some mouthwashes have a low pH which can lead to erosion.2,3

This is especially worse if patients use mouthwash straight before bed when their saliva flow is reduced. More importantly, it has been found that chlorhexidine containing mouthwashes can also trigger a severe anaphylaxis in allergic patients.4

Using mouthwash incorrectly alongside the supporting evidence that mouthwash is linked to diabetes/high blood pressure,5 raises the question on whether the potential harm of over the counter mouthwash can outweigh its benefits.

Although mouthwash still has its role, whether it is for post-surgery use or for xerostomia, its usefulness may be questionable and limited when it comes to daily use by the general population.

In our opinion, as more research is gathered surrounding the benefits and risks of regular mouthwash use, there may be various outcomes.

It might be worth considering the idea of restricting mouthwash advertisements or perhaps limiting mouthwash to prescription only.

We believe the dental team has a vital role in encouraging correct use of mouthwash or discouraging its use if they are being used incorrectly. It will be interesting to see the turn of events as new research is brought to light.


  1. 1.

    Preshaw P M. Mouthwash use and risk of diabetes. Br Dent J 2018; 225: 923-926.

  2. 2.

    Pretty I A, Edgar W M Higham S M. The erosive potential of commercially available mouthrinses on enamel as measured by Quantitative Light-induced Fluorescence (QLF). J Dent 2003; 31: 313-319.

  3. 3.

    Pontefract H, Hughes J, Kemp K, Yates R, Newcombe R G, Addy M. The erosive effects of some mouthrinses on enamel. A study in situ. J Clin Periodontol 2001; 28: 319-324.

  4. 4.

    Moka E, Siafaka I, Vadalouca A and Argyra E. Chlorhexidine: Hypersensitivity and anaphylactic reactions in the perioperative setting. J Anaesthesiol Clin Pharmacol 2015; 31: 145.

  5. 5.

    Bondonno C P, Liu A H, Croft K D et al. Antibacterial mouthwash blunts oral nitrate reduction and increases blood pressure in treated hypertensive men and women. Am J Hypertens 2015; 28: 572-575.

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Correspondence to A. Dagher.

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Dagher, A., Hannan, N. Mouthwash: more harm than good?. Br Dent J 226, 240 (2019).

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