Few "whitening" toothpastes are effective stain removers, according to a study in the British Dental Journal (2000;188:620).
Toothpastes can remove extrinsic stains through either a physical, abrasive action or by chemical means, say Professor Martin Addy (professor of periodontology, Bristol dental school) and colleagues. Most ordinary toothpastes contain abrasives. Whitening toothpastes tend to have an additional action through chemical agents such as organic solvents.
In a series of five studies, 28 whitening agents were tested on stained acrylic, which stains in a similar manner to enamel, the authors say. The degree of stain removal was assessed using optical density readings.
The results showed that two toothpastes, Macleans Whitening and Aquafresh Whitening, performed consistently well in the tests. These products showed 85-100 per cent stain removal after five minutes. The time taken for 75 per cent of stains to be removed was also measured. It was found to be shorter for these two products compared with other whitening agents. The authors comment that most treatments did not achieve 50 per cent stain removal and some gave results little different from water.
Professor Addy and colleagues conclude: "The majority of whitening toothpaste products performed poorly in terms of chemical stain removal. . . . In the more demanding oral environment, where the product is in contact with individual teeth for relatively short periods, most of these products would not benefit tooth colour through a chemical stain removal process."
Toothpastes may be accredited by the British Dental Association if they demonstrate dental health benefits (eg, reduced decay, healthier gums). The BDA says that a whitening toothpaste would have to demonstrate effective cleaning and dental health benefits to be accredited. The only such toothpaste to be accredited at present is Macleans Whitening. Commenting on Professor Addy's study, the BDA said that if whitening toothpastes encouraged people to brush their teeth then it was a good step towards oral health. It added that a concern about whitening toothpastes was the level of abrasive materials in the product, but that the "main whitening toothpastes have abrasivity levels that are comparable with normal family toothpastes".
A spokesman for Smithkline Beecham Consumer Healthcare (manufacturer of Macleans and Aquafresh) told The Journal on June 14 that it had no plans to apply for accreditation for Aquafresh Whitening. While Macleans was a UK-specific brand, Aquafresh was an international brand for which BDA accreditation was less important, he said.