The growing number of at-home and beauty salon tooth-whitening treatments on offer is making dentists nervous for their patients' health.
The products used by beauticians and found in chemists are not safe, according to dentists, and could be both harmful to patients and in some cases, illegal.
Dr Wyman Chan, CEO of smilestudio, said the popularity of pearly-whites is driving beauticians' move to administer treatments, but their processes could be harmful.
"My concern is that there are too many unsupervised treatments out there now, and at beauticians," said Dr Chan.
"Over the counter, at least people are buying at their own risk – but a beautician prescribing it to their patients when they're not properly trained is worse."
Dental processes can cost between £300 and £1,300, making the cheap but potentially harmful £10 fix of over the counter or beautician treatments more attractive.
The problem is, according to dentists, that the beauticians are using far more than the legal limit of hydrogen peroxide to get instant results, which can cause ulcers and permanent enamel damage.
The General Dental Council condemns the unsafe beautician dentistry and considers it illegal.
Dr Chan added: "I think the treatment should be done by dentists – after all you have only got one set of teeth and you should look after them."