A Melbourne magistrate has handed down a long-awaited decision today on whitening treatments offered by non-dentists, effectively banning beauty therapists from offering whitening treatments.

As part of her judgement, the magistrate, Ms Crowe, dismissed the defence argument that the procedure was non-invasive and therefore not covered by legislation, saying the intent of the legislation was to protect the public. She recorded a conviction and fined the beauty therapist $2000.

ADAVB Vice President Dr Anne Stewart welcomed the decision, saying that it would send a clear warning to the public about the dangers of having teeth whitened by non-dentists.

The Age newspaper today reported that Greensborough beauty therapist Suong ''Becky'' Van Thi was convicted and fined $2000 as an unregistered person who performed ''invasive or irreversible'' procedures by whitening teeth in a beauty salon.

The paper added that the decision gives the Dental Practice Board of Victoria, the relevant prosecuting agency, a legal precedent with which to charge other unregistered people who perform teeth-whitening procedures.

The Dental Practice Board of Victoria took the action after receiving a complaint from a customer who had undergone tooth whitening. The customer suffered severe mottling of her teeth, marbled teeth, ulcerations to her gums and chemical burns.

The Age reported that the beauty therapist had applied a bleaching cream containing six per cent peroxide to a client's teeth as part of a whitening procedure.

As reported in the current issue of Bite magazine, some beauty therapists use an even greater concentration of hydrogen peroxide in tooth whitening treatments, and other anecdotal reports we have received from dentists indicate other beauty therapists are using concentrations as high as 22 per cent.

The magistrate ruled that tooth whitening constitutes an “invasive and irreversible procedure” and that people registered as dental care providers may only carry out tooth whitening. The therapist’s defence team has indicated she will appeal the decision.

In related news, a study recently published in the Journal of the American Dental Association disputes previous data that stronger solutions of carbamide peroxide keep teeth whiter for longer periods of time.

The study, conducted by Brazilian researchers, involved 92 subjects undergoing teeth whitening using custom-fitted trays. The subjects were randomly assigned either a 10 per cent solution or a 16 per cent solution of carbamide peroxide.

Each person received whitening treatment two hours a day for three weeks. Researchers looked at tooth whiteness before bleaching, one week after treatment, six months later and a year later.

At the one-week and six-month time periods, the 16 per cent group had whiter teeth than the ten per cent group. But after a year, the 16 per cent group had lost some whiteness. By then, both groups' teeth were about the same shade. Their teeth were still whiter than before bleaching, however.

Previous studies had only followed subjects for a few months.

The researchers also asked people questions about the foods and drinks they consumed. Some food and drink is more likely to stain teeth. People in both groups ate and drank about equal amounts of tooth-staining foods. Very few people used whitening toothpaste.

The study appears in the September issue of the Journal of the American Dental Association.