THE DARK SIDE OF TOOTH WHITENING
By: Ted Huppert DDS: Guest Dental Columnist
It seems like everyone is whitening their teeth these days. There are commercials on television and radio, endless ads in the print media, and kiosks in the mall, all devoted to whitening teeth. But is there a problem? Well, maybe.
All tooth whiteners are bleaches and they all use one of two whitening agents, hydrogen peroxide or carbamide peroxide, which converts to hydrogen peroxide in the mouth.
The only difference is the concentration of the bleach. Everything else—flavor, color, delivery system, viscosity (the gooeyness)—is marketing.
Right now, the most popular technique for whitening is the one-visit zap, in which a tray is used to hold a strong bleaching agent against the teeth for a proscribed period of time. Then, the tray is removed from the mouth and the bleaching agent rinsed away. Presto! White teeth! The thing is, the bleaching agent must be strong to act so quickly, and frequently, the result is tooth sensitivity to cold, sweets, and all sorts of things. Fortunately, the sensitivity is usually temporary and will go away by itself, although in some cases, desensitizing toothpaste will be helpful. There may also be temporary redness or soreness of the gums.
There is a system that is employed in the dental office setting in which the teeth are isolated and the gums covered with a protective material, then the bleach is applied to the teeth and often warmed with a heat lamp or laser, although some studies indicate that the warming does not enhance the bleaching. This system is usually quite effective and has less chance of unwanted side effects because of the operator’s control over the placement of the bleach and the time of the exposure.
There are also at-home techniques in which a tray is made from an impression of the patient’s mouth and the patient uses a bleaching product at home whenever it is convenient. These products are usually not as strong as the one-visit bleaches, so repeated use and occasional touch-up may be necessary. They are safe and effective, although as with the one-visit bleaches, temporary tooth sensitivity and gum soreness can occur.
Back to the mall. There are currently tooth-whitening kiosks in some malls where the customer is guided through the bleaching technique by an attendant, who is generally wearing scrubs and/or a clinical jacket, but who may or may not have any dental training whatsoever. Many states have already or are in the process of passing legislation to make this illegal because of the possibility of doing irreversible harm to the consumer. At first, the vendors were accused of practicing dentistry without a license. But they got around that by having the customer place the tray in the mouth themselves. “Hey! We aren’t practicing dentistry! We don’t touch the customer!†Laws are being enacted to include loading of the trays and instructing the consumer in the definition of practicing dentistry. These places are potentially dangerous. Avoid them.
Is bleaching safe? Right now, if done properly, it seems to be. The bleach does not weaken the enamel or make it more prone to decay. What we aren’t sure of is exactly how far into the tooth the bleach penetrates. The enamel of the teeth is very hard, but the dentin which underlies the enamel is much softer and actually has micro-tubules that run all the way down to the tooth pulp. The dental pulp—the nerves and blood vessels inside the tooth—is a sensitive organ, and if bleach should penetrate into the pulp, damage may occur. As far as I know, this has not been shown to happen. But, I would use some discretion if younger people want to bleach their teeth. The pulp chamber shrinks as we age, so the younger the patient, the larger the pulp chamber is, which makes it closer to the surface of the tooth. The bleach would not have to penetrate as far to reach the pulp in young patients. For adults, bleaching is safe.
Can you overbleach? Yes, you can. Using bleach too frequently will not necessarily physically harm the teeth. But tooth enamel has a natural translucency and a degree of fluorescence, which means it will glow under black light. Cool! Overbleaching can mask those properties, making the teeth white, but unnaturally flat and opaque, as if the teeth were painted with white-out. That looks creepy.
What about the whitening toothpastes and mouthwashes? They do contain bleach and they do lighten a little, but if they contained enough bleach to significantly whiten the teeth, a prescription would be required to get them. They can make a good follow-up to maintain whiteness after professional bleaching however.
So, go ahead and whiten if you wish. It won’t do you any harm as long as the bleaches are used as directed. Just be careful not to overdo it. For a picture-perfect smile, you need to know when to quit.
