From today, those under the age of 18 will not be allowed to have their teeth whitened, following the introduction of strict new EU regulations.

The new EU directive regulates the use of the chemical used in tooth whitening products - hydrogen peroxide.

It states that from today, consumers can only be sold whitening products that contain no more than 0.1% hydrogen peroxide. Products that contain more than that will have to be administered by a dentist in the first instance.

However, products with more than 6% hydrogen peroxide are now illegal.

This means that anyone who wants to undergo tooth whitening must be examined by a dentist and have their first treatment carried out by that dentist. Any further treatments must be undertaken on the prescription of the dentist.

According to Tom Feeney of the Irish Dental Association (IDA), these new regulations will enhance patient safety.

"The dentist must examine the patient to determine whether tooth whitening is a suitable treatment option and to ensure the absence of risk factors in the mouth.

"The new regulations ensure that qualified dentists are carrying out what is a dental procedure, that safe products are being used and that the treatment is restricted to those over 18," he explained.

Dr Feeney also emphasised that tooth whitening should only be carried out, at most, once a year. Furthermore, the procedure is not recommended for heavy smokers, heavy drinkers or pregnant women.

Meanwhile, the IDA has again warned people not to purchase tooth whitening products over the internet, as some contain dangerously high levels of hydrogen peroxide, while others contain so little of the chemical, they are ineffective.