Teeth whitening kits on high street can cause 'significant damage'

Some high street teeth whitening products "have the potential to significantly harm" our teeth and should be banned, according to a new study.

Five over-the-counter products - available from Boots and Superdrug - were tested to determine whether or not non-hydrogen peroxide products are safe.

Dr Joseph Greenwall-Cohen, lead author of the study, said they found "significant damage to the surfaces of teeth, similar to what you'd see if you used a highly acidic product on a tooth".

He added: "What we saw is a change in the appearance of the teeth, it looked almost like they'd been scratched.

"There's such an ease of accessibility of these products, you would want there to be some evidence to justify how safe they are, but there was very little evidence to show how safe and effective they were."

The past decade has seen a rise in the development of non-hydrogen peroxide whitening products.

In 2011, a European directive was introduced to ensure that bleaching with higher strengths of hydrogen peroxide could only be carried out by dentists.

It has meant that DIY home kits can only contain less than 0.1% hydrogen peroxide, a level that's too weak to have much of a whitening effect.

As a result, manufacturers are increasingly turning to alternative ingredients to get around the directive, which - according to the research - could be even more damaging for our teeth.

The study, published in the British Dental Journal, raises concerns about the active ingredient sodium chlorite. It was found in three of the products tested (Mr Blanc Teeth, Janina Ultra White Strips and the Brilliant Five-Minute Kit).

Researchers found "substantial evidence" of how products which also contained a bonding agent called EDTA and citric acid "seriously damaged the hardness and strength of teeth".

The study warns that, as a result, we could start seeing widespread enamel damage in the next few years.

The British Dental Association's scientific adviser, Professor Damien Walmsley, said: "At best, people may be wasting their money buying over-the-counter and online products to whiten teeth… the lack of clarity over chemicals used in over-the counter and online products means you could be gambling with your teeth."

A spokesman for Boots said: "The safety of our customers is extremely important to us and we thoroughly assess all of our dental care products before we put them on sale."

Superdrug responded: "We will be reading the British Dental Journal's report with interest. The safety and well-being of our customers is always our primary concern and we are always happy to work with official bodies taking their research and guidance on board."

When approached for response, the manufacturers of Janina Ultra White Strips said the product has now been "delisted".

Mr Blanc Teeth and Brilliant Five-Minute Kit did not reply to our request to a response.