UCLan dentistry research directly links infected teeth and Alzheimer’s disease

The new findings by UCLan’s Dr Shalini Kanagasingam, published in the Journal of Alzheimer’s Disease Reports, show that fragments of the ‘amyloid-beta’ – a protein which collects in the brains of those suffering from Alzheimer’s disease and subsequently kills nerve cells in the brain – has also been detected in infected teeth.

It is recognised that one of the two main lesions of brain damage in those suffering from Alzheimer’s is an extensive build-up of amyloid-beta protein in the brain, and new therapies being approved for early Alzheimer’s treatment have focussed on reducing the deposits of these proteins.

Although it has largely been believed that amyloid-beta is produced by cells in the brain, scientists now understand that these proteins are released by the body as a response to infection and can therefore be produced by all cells in the body.

Because oral diseases are driven by infections, there is an abundance of amyloid-beta within and around the external surfaces of infected teeth, which may then filter into the blood circulation, where it could be transported to the brain.

UCLan’s laboratory-based investigation, led by Dr Shalini Kanagasingam and her supervisory team, examined extracted teeth which had root canal infection and gum disease. The results revealed that amyloid-beta can be produced in the mouth in response to oral bacteria involved in gum disease and root canal disease. This may act as a potential early risk for Alzheimer’s, as the sticky protein can be seeded from one site to another – for example, between patients via contaminated dental instruments.

This method of spread has been observed previously with different proteins known as prions, which can result in a fatal neurodegenerative disorder called Creutzfeldt-Jakob disease. As a result, in 2006, special guidance was issued to say that root canal dental instruments should only be used once, since prions are not susceptible to dental sterilisation procedures.

If the same can potentially be said for amyloid-beta protein, it prompts the consideration of whether it’s possible that Alzheimer’s can be spread via contaminated dental instruments. Dr Shalini Kanagasingam says that this risk is very low, and the research underlines the importance of everyone visiting the dentist regularly.

She explained: “People should be reassured that here in the UK, we have very strict and effective dental protocols in place to prevent cross-infection between patients. For example, root canal instruments are only ever used once. The findings of this study do not suggest dental procedures pose a risk of spreading Alzheimer’s disease; but they do really highlight that amyloid-beta, which is found in the brain of Alzheimer’s sufferers, is very much present in infected teeth, with root canal infection and gum disease.

“This study is the first to link both of these oral diseases with Alzheimer’s disease via amyloid-beta protein, and if anyone notices that they’re suffering from symptoms such as bleeding gums, bad breath, loose teeth, gum swellings or toothache, they should seek help from their dental team as soon as possible. Early diagnosis is vital, as successful treatment and management of these oral health issues are a key part of protecting your long-term brain and general health.”