Brushing your teeth could lower the risk of falling seriously ill with coronavirus, scientists have claimed.
An international team of experts have speculated that the virus may spread into the blood after infecting the gums.
They came up with the theory after noting a number of patients had no inflammation in their airways yet severe infection in their lungs.
Normally Covid enters through the throat or nose and makes its way through the respiratory system to the lungs.
But the scientists said it was possible the infection could bypass the airways and go straight to the lungs after gaining entry through the gums.
If correct, it would explain why a number of studies have found people with gum disease and poor dental hygiene are more at risk of severe disease.
They said ‘simple oral hygiene’ such as brushing teeth twice a day for at least two minutes and using mouthwash after meals could cut the risk of severe Covid.
The hypothesis, backed by NHS experts, was published in the Journal of Oral Medicine and Dental Research.
University of Birmingham‘s Professor Iain Chapple, one of the lead authors of the paper, admitted more research was needed to shore up the link.
Most people catch Covid by breathing in viral particles expelled by an infected person. The virus then makes its way down the nose or throat into the lungs.
Birmingham University scientists suggested the virus could enter the body through the mouth and travel in the bloodstream. Their hypothesis is pictured above. This is not a proven route for Covid infection, and scientists said more evidence was needed
People with gum disease are more at risk of suffering a severe Covid infection, studies have suggested. Experts say brushing your teeth more regularly should prevent this
Initial observations of lung CT scans from patients suffering from Covid lung disease by NHS radiologist Dr Graham Lloyd-Jones led to a collaboration between medical and dental researchers from the UK, US and South Africa.
Their review, published earlier this month, sets out evidence suggesting the virus enters the body via the mouth and travels in the bloodstream.
They point to papers which have spotted the virus in the saliva and salivary gland, as proving that it is present in the mouth during an infection.
And others showing that in people with gum disease bacteria from the mouth have been identified circulating in the bloodstream, suggesting it is also possible for the virus to enter the blood through this route.
The illness weakens cells in the gums which, the experts suggest, allows bacteria in the mouth – which are much larger than viruses – to enter the circulatory system.
To explain their theory that the virus travels in the bloodstream, they pointed to Covid damage around blood vessels in the lungs.
They said blood clots in this organ – medically termed immunothrombosis – clearly suggested this area had been attacked by the virus.
Experts say clots in the lungs may suggest the body is fighting the disease, as it traps the virus at affected tissue and stops it spreading further.
WHAT IS GUM DISEASE?
Gum disease, or periodontitis, is sparked when the gums become swollen, sore or infected.
In severe cases, it can lead to tooth and bone loss if it isn’t treated.
It is sparked when there is a build-up of plaque – a sticky substance containing bacteria – on the teeth.
Some bacteria in this concoction are harmless, but others can be damaging.
Experts say that simply brushing your teeth twice a day and flossing will remove this plaque, and stop the disease.
More than half of UK adults suffer from the disease, and 47 per cent of adults in the US are also thought to have the condition.
Symptoms can include:
- Swollen or puffy gums;
- Bright red gums;
- Gums that feel tender to the touch;
- Gums that bleed easily;
- Bad breath;
- Pain when chewing;
- Loose teeth;
Source: NHS England
In people dying from Covid, they added that studies have also observed sections of their lungs die after their vital blood supply is cut off due to clots.
On the other hand, the key features of pneumonia – thickened lung walls and mucous in the small airways – are not present in Covid cases.
‘In summary, the radiological findings are not consistent with dominant or primary airways disease but rather are entirely consistent with a disease of the lung blood vessels occurring first,’ they write in the paper.
Professor Chapple said gum disease and cavities make it easier for bacteria and viruses to enter the body.
From there it is able to travel around the body through the bloodstream, which is why many patients have problems with other major organs following a severe bout of the disease.
He implied the use of sterilising mouthwashes to prevent the virus entering the body through the gums could lower the risk of severe Covid, a theory which has been touted by researchers previously.
Professor Chapple added: ‘Gum disease makes the gums leakier, allowing microorganisms to enter into the blood.
‘This model may help us understand why some individuals develop Covid lung disease and others do not.
‘It could also change the way we manage the virus – exploring cheap or even free treatments targeted at the mouth and, ultimately, saving lives.’
‘Simple measures, such as careful toothbrushing and interdental brushing to reduce plaque build-up, along with specific mouthwashes, or even saltwater rinsing to reduce gingival inflammation (gum inflammation), could help… mitigate the development of lung disease and reduce the risk of deterioration to severe Covid.’
The research team comprised of experts from Salisbury District Hospital, UK; the University of Birmingham, UK; and the Mouth-Body Research Institute, Los Angeles, California and Cape Town, South Africa.
Commenting on the research Professor Damien Walmsley, from the British Dental Association, said more evidence was needed.
‘It is an interesting study but more research is needed to prove the link.
‘The best way to maintain good oral hygiene is to brush teeth thoroughly twice daily with a flouride toothpaste, before going to bed and on one other occassion.’
There is already some evidence that gum disease can lead to a more severe Covid infection among patients admitted to hospital with the disease.
A College of Dental Medicine, Qatar, study followed 500 patients hospitalised by the disease, almost half of whom were suffering from gum disease.
They found those with mouth problems were nine times more likely to die from Covid, and five times more likely to be put on a ventilator.
But the scientists suggested patients’ pre-existing condition may have triggered a more severe immune response, rather than their oral health. The study was published in the Journal of Clinical Periodontology.
Gum disease affects more than half of people in the UK, according to estimates, and 47 per cent of adults in the US.
It is triggered by damage to gums in the mouth, which may then lead to tooth and bone loss.
This can be triggered by a build-up of bacteria due to failures to brush the teeth regularly.
Scientists add this damage done to the gums can also open them up to infections from other organisms – like Covid – because they are inflamed and less able to withstand assaults from other organisms.