| COSMETIC DENTISTRY | OPINION
available, although their low pH has the potential to corrode the teeth. Whitening of the teeth is normally
carried out in one of four situations: ■ Professional tooth whitening in the dental office
■ Dentist-prescribed and/or dispensed treatments for use in the home
■ Home whitening using commercially available OTC products
■ The use of tooth whitening kiosks in places such as shopping malls or tanning parlours.
Over-the-counter products A number of OTC tooth whitening systems are available. Perhaps the most simple are tooth-whitening toothpastes, which are similar to ordinary toothpastes in that they contain a mild abrasive substance (such as baking soda). Whitening toothpastes also contain hydrogen peroxide or carbamide peroxide. However, even when they are used two or three times per day they are generally in contact with the teeth for too short a time to exert any real bleaching. They therefore have, at best, a marginal effect. An alternative approach is to use a
tooth-whitening mouth rinse. However, for reasons similar to those that apply to toothpastes, they have at best a mild effect. Slightly more effective are whitening
strips which are applied to the teeth for periods varying from 30 minutes to a number of days. The strips comprise a flexible plastic, usually
with peroxide gel that enable the bleaching agent to remain in contact with the teeth for up to 45 minutes. Despite their limited efficacy, OTC
polyethylene,
coated with a hydrogen peroxide-containing gel, and are not normally visible when in use. They are purchased in a kit that contains separate strips for the upper and lower teeth. One of the drawbacks with strips is that
the teeth are not flat, and so some teeth, or parts of the teeth, get more exposure than others. So while a bleaching effect is achievable, it can be somewhat uneven and result in the teeth looking less attractive than previously. More recent additions to the range of
OTC products available are teeth-whitening pens, which take the form of a click applicator for applying a precise amount of peroxide gel to the teeth, and whitening trays. Pens are claimed to be safer, because they keep the peroxide away from the gums and other soft tissues, and relatively good effects have been reported. Whitening trays consist of flexible plastic trays prefilled
products remain popular on grounds of cost, choice of product, and convenience. Many of the products available on the market come from the same companies associated with more traditional dental products, such as Crest (Procter and Gamble), Aquafresh (GlaxoSmithKline) and Listerine (Johnson & Johnson).
In-office whitening Compared with OTC tooth whitening, in-office whitening offers a number of advantages including faster results, greater safety, and less likelihood of tooth sensitivity, partly owing to the nature of the peroxide formulations used and partly owing to the use of desensitising agents. In addition, it is more likely to be effective against certain types of stains. Its major disadvantage, of course, is the cost, which can run to several hundred dollars. In-office procedures usually begin with
a careful examination of the teeth (and treatment of any problems found) followed by a thorough cleaning. A liquid
rubber or resin material is painted onto the gums, which hardens to protect against accidental exposure to the whitening material. Next, a bleaching gel, usually based on hydrogen peroxide, is applied to the teeth (teeth at the back of the mouth which are not usually visible are not treated) and left for up to 30 minutes, after which it is washed off. After the teeth have been checked to observe the extent of the whitening, the application of whitening gel may be repeated for a further one or more cycles. Finally, the gel is removed, the patient rinses, and the colour checked (it is normal at this stage for the teeth to appear slightly whiter than normal as a result of dehydration ® the final colour appears after 2 or 3 days). A number of proprietary whitening
systems are available for in-office use, including BriteSmile Whitening Procedure Kits (Discus Dental, which became part of Philips Oral Healthcare in 2010); the Lumibrite Chairside Whitening System (DenMat Holdings); and Opalescence Boost (Ultradent Products). Some of these systems use a light source, similar to that used to harden composite filling
prime-journal.com | March 2012 ❚ 83
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