JUST IN: How Brushing Your Teeth Can Keep You Safe From COVID-19

Brushing your teeth whenever you leave your home may help ward off Covid-19, a dentistry professor has claimed.


Professor Martin Addy, of the University of Bristol, argued toothpaste has the same chemicals as antibacterial hand gel.

This, he claimed, could kill the coronavirus if it enters through the mouth, stopping it from replicating and causing illness. It could protect others by cutting down the viral load in the mouth, which research has suggested may be linked to how contagious a person is.  

Transmission of the coronavirus between people is mostly through droplets from coughing or sneezing, which can be picked up from surfaces. But the virus doesn't only cause an infection through the mouth — it can enter the body through the nose and eyes, doctors say.

Professor Addy claimed people should brush their teeth every time they leave their home, such as when they do their food shop or exercise. 

And he called for the Government to encourage the public to clean their teeth more often in the same way as they recommend face-mask wearing and hand washing. 

Mouthwashing has also been suggested to remove viral particles from the mouth and prevent an infectious person from spreading it to others.

Speaking to The Telegraph, Professor Addy said: 'Toothpaste contains the same detergents as those found in handwash gels recommended.

'The antimicrobial action of toothpaste in the mouth persists for three to five hours and, thereby, would reduce the viral load in saliva or infection by viruses entering the mouth.' 

He added: 'For the vast majority, the timing of tooth brushing should be focused when they are about to go out of their homes for exercise or shopping.

Mouthwash could stop coronavirus transmission, according to scientists in Germany.

Virologists led by Ruhr-Universität Bochum, in west Germany, tested eight mouthwashes with different ingredients that are available in pharmacies or drugstores in Germany.

They mixed each mouthwash with virus particles and an interfering substance, which was intended to recreate the effect of saliva in the mouth. The mixture was then shaken for 30 seconds to simulate the effect of gargling.

Then they measured the virus titer, which is a value given to the quantity of virus in a volume of fluid, in this case saliva. 

Three mouthwashes reduced it to such an extent that no virus could be detected after an exposure time of 30 seconds. More research is needed to understand whether this actually prevents spread of the virus, and how long the effect lasts. 

The team headed by Toni Meister said their research does not prove mouth rinses are suitable to protect against catching the coronavirus, or treating it.

Ms Meister said: 'Gargling with a mouthwash cannot inhibit the production of viruses in the cells, but could reduce the viral load in the short term where the greatest potential for infection comes from, namely in the oral cavity and throat – and this could be useful in certain situations, such as at the dentist or during the medical care of Covid-19 patients.'

Researchers in Lima, Peru, also encouraged mouthwash for dentistry procedures to protect against the coronavirus.

Andrea Vergara-Buenaventura, Department of Periodontics, Universidad Científica del Sur, looked at the evidence for a range of conventional antiseptic mouthwashes used in dentistry for protecting against infectious diseases.

She and colleagues concluded in their paper: 'Within the limitations of this brief review and despite little clinical evidence, we suggest the use of preprocedural mouthwashes in dental practice to reduce SARS-CoV-2 viral load from previous dental procedures and to reduce the cross-infection risk while treating patients during the pandemic.  

'Research is urgently needed to determine its potential for use against this new virus.'

Professor Addy said antibacterial agents in toothpaste could help eliminate the coronavirus if enters via the mouth. In theory, this would make it less likely to cause illness, but has not been proven.

Researchers have said cutting down the dose of virus the person is exposed to may reduce the risk, and severity, of disease.

And the amount of virus exposure at the start of infection is also linked to a higher viral load, which relates to how infectious a person is to others.

Members of the Oxford Covid-19 Evidence Service Team in March: 'The initial dose of virus and the amount of virus an individual has at any one time might worsen the severity of Covid-19 disease. The amount of virus exposure at the start of infection – the infectious dose – may increase the severity of the illness and is also linked to a higher viral load [in infected patients].'

It isn't the first time Professor Addy has promoted the idea of brushing your teeth more often to reduce the risk of Covid-19. 

In a previous letter to the British Dental Journal in April, Professor Addy said he was surprised the dental profession had not been promoting teeth brushing as a preventative approach to coronavirus.

He wrote: 'From my own knowledge and listening to experts, a major source of droplets are derived from saliva. 

'I am therefore somewhat surprised that our profession has not been promoting oral hygiene, through toothbrushing with toothpaste, in the preventive approach to Covid-19. 

'The majority, if not all toothpastes, contain detergents, which confer significant antimicrobial properties to the product, indeed the same detergents are present in many hand washing formulations, recommended against coronavirus.'

He said the Government should be encouraging everyone to brush their teeth for two minutes, twice a day.

Although everyone should be brushing their teeth twice a day already, Professor Addy said many who are at a greater risk of Covid-19 fail to do so, such as the elderly who may rely on a carer.      

Professor Addy did not go into detail about which chemicals in the toothpaste may be protective against the coronavirus. 

Triclosan is an antibacterial agent commonly added to toothpastes in order to prevent plaque build-up.

The majority of antibacterial soaps contain triclosan, though other chemical additives are also common.

Triclosan is a controversial chemical that's been banned by the US Food and Drug Administration (FDA) in 2016. 

It said there was insufficient information on the long-term health effects of 19 antibacterial chemicals and a lack of evidence on their effectiveness, banning them from products in America from 2017.  

Professor Addy also addressed the idea of using mouthwash more often to protect against Covid-19, in his BDJ letter.

He promoted chlorhexidine products specifically due to their 'antiviral action'. But he admitted there is little research to prove they will be effective against the coronavirus. 

However since then, a study by scientists at Korea University College of Medicine, Seoul, found SARS-CoV-2 was suppressed for two hours after applying chlorhexidine, suggesting it may be able to control Covid-19 transmission.

They concluded: 'Chlorhexidine mouthwash was effective in reducing the SARS-CoV-2 viral load in the saliva for a short-term period.'  

Mouthwashes are used for rinsing the mouth before a dentistry procedure to reduce germs in aerosols and spatter produced during dental procedures.

Coronavirus particles are coated with a fatty membrane which protects the genetic material inside. 

It can be broken down by antibacterial gel and soaps, but not necessarily mouthwash.

The World Health Organization rubbished the idea that mouthwash was protective in February.

It said some brands or mouthwash can eliminate certain microbes for a few minutes in the saliva in your mouth. 

'However, this does not mean they protect you from 2019-nCoV infection,' WHO said, before the coronavirus was given its formal name of Covid-19.

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