A lack of clarity over the chemicals used in high street teeth whitening kits means consumers could be “gambling with their teeth”, experts have warned.
Some popular high street whitening products have the potential to cause “significant damage” to the surfaces of teeth and should be banned, a new study claims.
In 2011, a European directive was introduced to ensure bleaching with higher strengths of hydrogen peroxide could only be carried out by dentists, meaning home DIY kits can only contain less than 0.1 per cent hydrogen peroxide.
This level is too weak to result in a significant whitening effect, and has seen manufacturers increasingly turning to alternative ingredients instead, which could be even more damaging to teeth.
Five over-the-counter kits sold in high street stores Boots and Superdrug were tested as part of the study, published in the British Dental Journal, to determine whether non-hydrogen peroxide products are safe to use.
The researchers found that three of the products (Mr Blanc Teeth, Janina Ultra White Strips and the Brilliant Five-Minute Kit) contained an active ingredient of sodium chlorite, which reduced the hardness of teeth when acid was present and increased the chances of surface abrasions.
Dr Joseph Greenwall-Cohen, lead author of the study, said: “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 study found “substantial evidence” of how products which contained a bonding agent called EDTA and citric acid caused serious damage to the hardness and strength of teeth.
Researchers warned that high street bleaching products can vary and not all are safe to use, advising consumers to exercise caution when selecting bleaching or whitening products to apply to their teeth.
The study also warned that the lack of clarity over ingredients contained in such products could result in widespread enamel damage over the next few years.
Professor Damien Walmsley, the British Dental Association’s scientific adviser, said: “At best, people may be wasting their money buying over the counter and online products to whiten teeth.
“Home whitening kits are likely to take longer and be less effective than treatment from the dentist.
“While hydrogen peroxide, as used in dental practices, is the gold standard for whitening teeth, the lack of clarity over chemicals used in over the counter and online products means you could be gambling with your teeth.”
In response to the findings, 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.”
A spokesperson for Superdrug said: “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.”