Dental experts are calling for a ban on non-hydrogen peroxide based whitening kits which can be sold over the counter, after tests of five common brands found they could harm enamel.
Damage was visible in tests on extracted teeth which had been whitened in line with the manufacturer’s instructions, according to the study published in the British Dental Journal on Friday.
However, home users could cause further damage by applying them for too long or more frequently, or if they have underlying dental problems that would take a dental inspection to pick up, the authors said.
“The lack of research and ease of availability of these products from major retailers is alarming and may potentially be harming the consumers’s dentition,” Dr Linda Greenwall, one of the authors from Manchester University said.
An array of reformulated whitening products have flooded the market after a 2011 EU directive which said products containing more than 0.1 per cent hydrogen peroxide could only be sold to dentists.
Although they will have had safety testing, Dr Greenwell and her colleagues said longer-term effects in real world situations are poorly understood.
Three of the products tested in the BDJ study contain sodium chlorite, an ingredient which can react in the mouth to produce chemicals shown to harm enamel.
In tests on 21 extracted teeth all five products were tested under an electron microscope, that can pick out microscopic changes in their surface.
While all showed changes, samples treated with the “Brilliant 5-minute kit” and “iWhite instant teeth whitening” had the biggest effects, and also showed significant softening meaning treated teeth are more vulnerable to abrasions.
When they tested the whitening effects two were found to have whitened the teeth less than the samples which had only been treated with saline, meaning users may have wasted time and money.
“The British Dental Bleaching Society is calling for all dentists to be trained in tooth-whitening and bleaching. We are concerned that the OTC products included in the study may be harmful to teeth and advise the general public to see their dentist if they are considering having their teeth whitened,” a spokesperson said.
A Boots spokesperson 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.”
Cosmetic procedures are increasingly offered on the high street but have raised fears about poor regulation and the potential harm of trying to emulate the look of reality TV stars.
Superdrug recently announced it would run mental health checks on people looking to get botox in its stores. Superdrug was approached for comment.