In my last blog, I discussed in-office bleaching. The other method for lightening teeth is done at home. There are over the counter products and ones that are professionally available at your dentist’s office. The over the counter products seem to work OK for teenagers and young adults, however, with older adults, the professional variety works much better. My speculation is that the stains have been there much longer and are more resistant to the bleaching process.

Custom Tray

In our office, we make a custom tray, essentially an ultra-thin, clear mouthpiece to hold the bleach in the mouth. The bleach that we use is slightly viscous and sticky so it doesn’t run all over the mouth during use. I instruct my patients to sleep with the mouthpiece in all night. The process can take anywhere from 2-6 weeks, but the bleaching solution is not near as harsh as the in-office variety and is much kinder and gentler. This greatly reduces the incidence of sensitivity. Studies have shown that after six months, the results between in-office and at-home bleaching is exactly the same. And other studies have shown that patient satisfaction hovers around 96% positive for at home and less than 50% for in-office.

There are two main methods for bleaching teeth: in office or at-home. In an office setting, a rubber-like substance is painted on the gums and then light cured. An extremely strong solution of hydrogen peroxide, usually 35%, is applied to the front teeth surfaces. The solution is left on the teeth for long enough to leach into the enamel and oxidizing the stains. This usually takes about 15 minutes. Some dentists employ the use of lights to accelerate the process. The lights can cause overheating of the dental pulp which contains the nerve and can greatly increase the sensitivity to temperatures. Studies have shown that the use of lights or “lasers” makes no difference in the final results. If there is an increased lightening right after the appointment with the use of lights, it has been shown that that is due to dehydration of the tooth surface and the color will return once the teeth have rehydrated. There are some desensitizing that the dentist can apply afterwards. These contain potassium nitrate. There are also toothpastes that are specially made for sensitive teeth that can help make an in-office bleaching procedure much easier to tolerate.

When bleaching one’s teeth, it must be kept in mind that the bleaching process will not effect the color of dental restorations such as tooth-colored fillings, bonding, or porcelain laminate veneers or crowns. It will not harm porcelain, but scanning electron microscope studies have shown some some minor pitting in composite (tooth-colored) restorations. Hypocalcified and fluorosed areas have stark white splotches. When initially bleaching the teeth, these areas tend to stand out dramatically, however, as time goes on, the surrounding tooth structure will begin to lighten, thus allowing the hypocalcification to blend in better. Teeth bleaching will not remove these splotchy areas, just make them less noticeable. Many people have grey stains in their teeth. These stains can be very resistant to the bleaching process. The products that cause the grey color do not appear to oxidize as well. On the other hand, yellow stains are very amenable to bleaching and will lighten very well. The nice thing about the grey stain is that it is not as noticeable from a conversational distance as the yellow, so the teeth can still have a light, appealing appearance even with some residual grey.

Before bleaching one’s teeth, they should have a thorough dental examination by their dentist. One would not want to place bleach over cavities. The bleaching process many times will cause the teeth to be sensitive, so placing bleach into a cavity could increase the sensitivity. Bleaching is also not recommended for children under 16 because their pulp chamber in the center of the teeth where the nerves reside are very large which could make for extremely sensitive teeth. The peroxide ion has been shown to give off oxygen free radicals which have been shown to cause tissue damage. That is something I would not want to take a chance with in a growing child. Other issues include the possibility of gum irritation. The bleaching solutions, especially at the higher concentrations, can be somewhat caustic, and can injure the gums. Most of the time, it is just a temporary reddening and discomfort. This can be reduced by cutting the bleaching time or by switching to a weaker concentration of the bleaching solution. Both sensitivity and gum irritation tend to go away when the bleaching is stopped.