No really, brush your teeth twice a day franckreporter/Getty

Bacteria that cause gum disease have been implicated as a cause of dementia. Here’s what you need to know.

What is gum disease and why should I be worried about it?

Gum disease, also known as gingivitis in its mild form, occurs when bacteria accumulate in tooth plaque, causing inflammation, receding gums and bleeding. If it progresses to the more serious form, periodontitis, it can lead to abscesses and tooth loss.

So why are we talking about it now?

It turns out that one of the key bacteria that cause gum disease – Porphyromonas gingivalis – may also be the root cause of Alzheimer’s disease, a form of dementia.


Yikes. How do I know if I have gum disease?

Occasional bleeding from the gums when you clean or floss your teeth doesn’t definitely mean you have it, as you may just have been too rough. But dentists advise that any bleeding should be checked out. Other signs include soreness around the gums and bad breath.

What should I do about it?

Researchers are working on a vaccine and a specific anti-toxin for P. gingivalis, but these are some years away from reaching the clinic. Until then, your best bet is taking the usual steps to avoid gum disease.

Which are?

Listening to your dentist, for a start. They advise cleaning your teeth twice a day, and flossing or using interdental sticks to get plaque out from the gaps. Too vigorous brushing can get oral bacteria into the bloodstream, so take it easy. But if plaque is allowed to build up it can become mineralised, turning into hard tartar, which encourages the growth of more plaque towards the tooth roots.

I may have left it too late…

If tartar has already taken hold on your teeth, it can’t be removed by ordinary brushing and must to be scraped off at the dentist. The UK’s National Institute for Health and Care excellence advises seeing your dentist at intervals ranging from 3 months to 2 years, depending on the state of your teeth and other health factors.

Anything else I should do?

All the usual general health advice applies here. Smoking makes gum disease worse and harder to treat. And a good diet and exercise regime reduces low-level chronic inflammation, which is bad for your gums and your brain. It may be no coincidence that general physical ill-health makes Alzheimer’s worse.

So are we all doomed?

Gum disease is very common – according to the UK’s National Health Service, most adults have it to some extent and clearly not everyone ends up with Alzheimer’s. There’s still much we don’t understand, but it could be a question of how much bacteria are present, or how good your body is at dealing with them.

Hang on, didn’t people used to be terrible at brushing their teeth?

You might think that our ancestors’ poor oral hygiene would make them more susceptible to Alzheimer’s, assuming that P. gingivalis is indeed responsible. But in the past, fewer people would have reached old age when Alzheimer’s rates increase. In the UK, for instance, about 30 per cent of people over 90 have dementia, but only 3 per cent of 70-75-olds.