How mouthwash can give you bad breath… AND stain your teeth

Many people include a daily swill of mouthwash in their dental routine to freshen breath and fight plaque – but could we actually be damaging our teeth in the process?

 

Some of the ingredients in mouthwash may have a detrimental effect on teeth and gums if the product isn’t used properly, says Robin Seymour, professor of restorative dentistry at Newcastle University.

 

Many mouthwashes contain alcohol —some are up to 26 per cent proof, research has shown. It’s used as a carrier agent, to allow ingredients such as menthol, eucalyptol and thymol to function — these help to penetrate and break down plaque.

However alcohol itself can cause dryness in the mouth, breaking down the mucus-like coating that keeps the mouth moist. This can lead to bad breath and, says Professor Seymour, cause an uncomfortable stinging sensation in the mouth.

Alcohol-based mouthwash has also been linked to an increased risk in oral cancer. Scientists in a study published in the Dental Journal of Australia in 2009 reported that the ethanol (alcohol) in mouthwash allowed cancer-causing substances such as nicotine to permeate the lining of the mouth more easily. A toxic breakdown product of alcohol called acetaldehyde can also accumulate in the mouth.

Some ingredients in toothpaste, such as the foaming agent sodium lauryl sulphate, can interact with the fluoride in mouthwash, and deactivate it so that it loses its effect. For this reason, wait at least half an hour after brushing before sluicing with mouthwash.

Some mouthwashes can even cause staining. This is due to a chemical called chlorhexidine gluconate — an antiseptic designed to reduce bacteria and remove plaque, both of which can lead to bad breath.

However, when regularly exposed to the teeth it can cause brown patches on the enamel because of a chemical reaction.

Some ingredients in toothpaste, such as the foaming agent sodium lauryl sulphate, can interact with the fluoride in mouthwash, and deactivate it

‘Chlorohexidine can produce tooth staining within about ten days of usage because it reacts with food additives which may be left on the teeth, particularly tannins, found in Coca-Cola, tea, coffee and red wine,’ explains Professor Seymour.

So should we just avoid these products altogether? According to Professor Damien Walmsley, scientific adviser to the British Dental Association, it’s always worth asking the advice of a dentist.

London-based dentist Dr Ogo Eze agrees: ‘If, for example, someone has gingivitis — inflammation of the gums — then it is important to keep plaque levels down, as this can make the inflammation worse.

‘The dentist may suggest a two-week course of a high-fluoride mouthwash such as Corsodyl to help reduce the risk of further decay. There is also a condition called acute necrotising ulcerative gingivitis, which is an acute infection of the gums.

‘A prescription mouthwash called Peridex contains oxygen which can counteract the micro organisms that cause this problem.’ Peridex also has a lower concentration of chlorhexidine than Corsodyl.

If you don’t have any dental problems, Professor Seymour suggests using an alcohol-free brand such as Oral B Anti-Plaque Alcohol-Free Mouth Rinse.

‘It doesn’t matter how minute the risk of oral cancer might be. It is such a significant disease that I don’t think there is any reason to take the risk of using a mouthwash that contains alcohol.’

To avoid staining, he suggests products such as Dentyl, which contain cetylpyridinium chloride (CPC) rather than chlorhexidine — both chemicals act as an antiseptic, but CPC won’t stain.

However, the chief executive of the British Dental Health Foundation, Dr Nigel Carter, says: ‘Many of the active antibacterial ingredients in mouthwashes require the presence of alcohol to exert anti-plaque effects and help to prevent gum disease.

‘Chlorhexidine is the “gold standard” antibacterial and is often advised by dentists for acute flare ups of gum disease to control the symptoms.

‘Chlorhexidine mouthwashes are not recommended for long-term use since they do have the side effect of staining. This can be removed by a dentist.’  

The British Dental Health Foundation recently reviewed all the evidence about the use of alcohol in mouthwashes and concluded that there is no evidence whatsoever of a link between mouth cancer and alcohol in mouthwashes.

A spokesperson for the Cosmetic, Toiletry & Perfumery Association, which represents manufacturers of mouthwash, adds: ‘All products available in the European Union are subject to stringent safety requirements and each product must undergo a safety assessment before it can be placed on the market.