People should get an oral health certificate from their dentist or dental specialist before getting their teeth whitened, the Health and Disability Commissioner says.

The recommendation follows a woman suffering severe mouth pain after having her teeth whitened by an unregistered practitioner.

Before the teeth whitening, the woman had her teeth scaled and polished by a dental hygienist, a report released by the Health and Disability Commissioner today said.

As a result, during the teeth whitening procedure and for two days after, part of her gums turned white, she suffered severe mouth pain and burning gums.

There is no legal requirement for teeth whitening to be performed by a dentist, and the woman knew the practitioner was not a dentist.

The person offering the whitening service was told of the woman's pain and changed the information given to patients, warning that carrying out teeth whitening too soon after scaling and polishing could result in discomfort. Clients were advised to wait 14 days between the two treatments.

The commissioner recommended those offering teeth whitening services change information given to clients " include advice to obtain an oral health certificate from a registered dentist or dentist specialist prior to undergoing teeth whitening".

However, there remained a risk that patients could be misled by the teeth whitener's assertions of having professional training and qualifications, and the commissioner asked the Ministry of Health to look into that aspect.

"This case highlights the risks of teeth whitening being carried out by persons who are not qualified to assess consumers' teeth or form conclusions whether their teeth are suitable for teeth whitening."