Dentists are warning Brits could damage their teeth by snapping up cut-price braces online.
Cheap orthodontics kits being sold on the internet come with videos that show how to fit and use the braces yourself.
Getting your teeth straightened at a traditional dentist usually costs between £2,500 and £5,000.
But one firm, SmileDirectClub, claims it can help people with “mild to moderate problems” for as little as £1,499.
The process normally begins with a 3D scan of your teeth in a high street shop or pharmacy. But the British Orthodontic Society has launched a campaign to warn about the risks of unsupervised treatment.
BOS president Jonathan Sandler said: “You could be in danger of having serious conditions missed, as well as inappropriate and dangerous treatment carried out.”
Dr Nigel Carter, of the Oral Health Foundation, said: “For many, it will feel a consumer-savvy choice. But orthodontics should always involve face-to-face contact with a trained professional.”
SmileDirectClub, which is opening shops in London, Manchester, Birmingham, Leeds, Cambridge, Newcastle and Cardiff, says customers can have consultations with a UK dentist by email, web chat or phone to see how the aligners are working.
Customers visit the shop, where a 3D optical camera creates an interactive 3D image of their smile, teeth and gum lines.
This image is then emailed to one of the firm’s registered dentists and orthodontists to see whether they can help the customer.
Alternatively, buyers can pay £39 for an at-home impression kit which is returned to the firm for assessment.
They are then sent a box of personalised 3D printed aligners, which are normally changed weekly as the teeth are moved and straightened.
But the British Dental Association urged caution. Vice chairman Eddie Crouch said: “If the treatment isn’t monitored over time, you may not get the best outcome and there is a risk of causing permanent damage.”
SmileDirectClub did not respond to a request for comment.