This statement is currently under the Canadian Dental Association review process.
The popularity of both tooth whitening and tooth bleaching has grown at unprecedented rates in recent years. In response to the public's interest, a wide variety of over-the counter and professional products and techniques to whiten or bleach teeth, including gels, pastes, strips, gums and rinses, are now available.
In the marketing of these products, the terms "whitening" and "bleaching" are often used interchangeably, which may lead to confusion among consumers. For the purposes of this statement, "whitening" is defined as a cosmetic process, and claims of whitening ability can be applied to any product that removes debris or staining from teeth through mechanical means. The effects of these products (typically toothpastes or gums) are relatively minor, and this position statement will instead focus on products whose primary purpose is to bleach the teeth, a more significant chemical effect that cannot be immediately reversed.
Current research supports tooth bleaching as a generally safe and effective method to improve tooth esthetics, provided it is undertaken under a dentist's supervision and according to the manufacturer's directions. During the initial consultation, the dentist will determine the cause of tooth discolouration, the likelihood that the desired effect will be achieved with bleaching and the potential for negative effects. Tooth discolouration may result from dental caries (tooth decay), aging, food and beverages, smoking, medications or other causes. Unlike natural enamel, crowns, fillings and other dental materials are unaffected by bleaching compounds and may appear darker relative to teeth that have been whitened by bleaching. In addition, in patients with irregular tooth discolouration (due to medication, aging or fluorosis), bleaching may yield irregular and unsatisfactory results, and other or additional treatment may be required.
The effects of tooth bleaching can be expected to last up to 2 years, depending on lifestyle choices such as smoking and consumption of staining foods and beverages. The degree to which teeth appear whiter, the evenness of shading and the speed at which the change occurs depend largely on the concentration of the bleaching chemicals and the mechanism of delivery (mouthguard tray, strip delivery or paint-on method). The current literature does not indicate that power- or light-assisted (laser) bleaching produces whiter teeth, although the bleaching process occurs more quickly with these methods.
Bleaching may cause adverse effects. When the products are used as directed, tooth sensitivity and soft-tissue irritation are the most common negative effects; these problems usually resolve on their own. If these or other side effects occur, use of the product should be discontinued and the dentist consulted. The long-term effects of repeated bleaching, especially if products are used inappropriately or excessively, are not yet fully understood but may include tooth pitting and pulp ("nerve") damage.
As with most elective procedures, tooth bleaching should be deferred until after pregnancy, since the bleaching products have not been tested in pregnant women. Bleaching products should not be used for children under 12 years of age.
CDA Board of Directors
Approved: November 2007
Reaffirmed: June 2013