Metal fillings ‘leak mercury after scan’

Metal dental fillings leak mercury if they are exposed to a new powerful type of medical scan, scientists have found.

They studied the effect of ultra-high-strength MRI – the latest in scanning technology being introduced to several research hospitals in the UK.

The study, in the journal Radiology, shows 20 minutes’ exposure is enough to release the toxin from extracted teeth filled with silver-coloured amalgam.

The team say more studies are needed to tell what real-life risk it might pose.

These cutting-edge scans are not yet widely used but are helping with medical research.

Leak risk

Although metal fillings are now being superseded by white, ceramic, composite fillings, they are still the most common type offered by NHS dentists.

They are often used on the back teeth because they are hard-wearing, while visible front teeth are usually given white fillings.

The British Dental Association says dental amalgam is safe. It’s been in use and extensively studied for 150 years as a restorative material. Its safety and durability are well established. And it remains the most appropriate material for a range of clinical situations.

It says there is no justification for removing these fillings as a precaution, except in those patients properly diagnosed as having allergic reactions to amalgam. This is a rare situation.

But the BDA agrees that more studies are needed to better assess this new potential risk linked with powerful medical scans.