Teeth Whitening FAQ’s

What determines the color of my teeth?

The color of teeth is caused by two different things:

#1 the pigments in the teeth from when they were formed

#2 the extrinsic pigments that over time penetrate the tooth

Over time these different pigments can join together causing teeth to appear darker and darker. Pigments on the surface of the teeth (extrinsic) stains slowly penetrate into the tooth and become intrinsic stains. The original pigment molecules from when the tooth was formed join together with the intrinsic stain pigments and form larger, darker pigments. Traditionally we think of teas, coffee, cigarettes, and red wine as big contributors to staining teeth.

How does teeth whitening work?

Whitening gels work by getting rid of these pigment molecules. Peroxide-based whitening products diffuse into the tooth and react with the color pigments. They work by breaking down large pigment molecules into smaller ones and also break down the molecular bonds in the pigments that are making them darker.

Does teeth whitening hurt?

Tooth sensitivity is a common side effect of teeth whitening. Usually the higher the concentration of peroxide and the longer the duration of its application, the greater the chance of tooth sensitivity. The sensitivity varies greatly from patient to patient and is transient, with symptoms disappearing in hours or, in rare cases, a few days.

Is teeth whitening safe?

Yes. In people with normal, healthy teeth and gums, bleaching is safe, but you should be examined for the presence of cavities, abrasion, attrition, exposed dentin or root surfaces prior to teeth whitening. This is why it is necessary for you to have a comprehensive exam before whitening. A dental cleaning before whitening is also a good idea.

Can you whiten your teeth too much?

No, but with most people there will be a diminished return because the teeth can only be whitened to a certain point. However, over time teeth will darken again and a touch-up may be required.

Why doesn’t your office use a light for bleaching?

The use of bleaching lights definitely adds flair to the procedure. However, the consensus of researchers not funded by manufacturers of bleaching lights and lasers is that they add no benefit to the whitening of teeth, and may actually add to discomfort.

The proponents for the light claim that the light adds extra energy to help change the whitening product to its active form. However, the kind of chemical reaction that leads to this activation actually releases energy—it does not take it in—so the lights may actually slow it down. Some researchers have also suggested that lights and lasers can increase temperatures inside of the tooth, increasing sensitivity. To say the least, this is still a contentious issue.

Do I need to have all my dental work completed before whitening my teeth?

As stated in part I, it is necessary for you to have a comprehensive exam before whitening to determine any presence of cavities, abrasion, attrition, exposed dentin or root surfaces. Additionally, if the doctor determines you need fillings or crowns on one or more of your front teeth (those that will be whitened), it is recommended that you have the work done first so that all front teeth will match.

What’s the difference between the gel my dentist uses vs those sold in stores?

Peroxide whitening gels and solutions are usually of two different types, Hydrogen Peroxide or Carbamide Peroxide. Through chemical reactions, both of them result in the same active ingredient and therefore can achieve the same whitening results and neither have been shown to cause more or less sensitivity than the other. However, the ones usually sold in stores (Carbamide Peroxide) have a longer shelf life, and as a result will take longer to achieve results, releasing about half of its whitening power in the first two hours and being active for up to six more hours. By contrast, the kind usually used by dentists (Hydrogen Peroxide) will release most of its whitening power in 30-60 minutes, giving you much quicker results.

What’s the difference between chairside vs take-home whitening?

With chairside or in-office whitening your teeth are usually whitened in one sitting that may take up to 1 ½ hours. The obvious advantage of this method is that your teeth should be noticeably whiter after just one appointment. The other method involves having whitening trays made that you take home with you. The trays are essentially custom-made, soft, plastic-like moulds that fit your teeth. You place whitening gel, provided by the doctor, in the trays and place them over your teeth for a specified length of time for a number of days.

One of the main differences between the two methods is the strength of the whitening agent. The in-office method uses a much stronger agent than the take-home method and, thus, is more likely to cause sensitivity. In fact, with in-office whitening the dental staff will use special methods and materials to prevent any possibility of the bleaching agent getting on your gums, cheeks, or lips, as it can cause some irritation. You should be aware that with any type of whitening there is a chance of having sensitivity after a whitening session.

Although take-home whitening takes longer to whiten your teeth, it does have its advantages. Aside from the lower likelihood of sensitivity, many enjoy the versatility it offers in having control over how white their teeth are getting. Additionally, having the trays allows for touchups in the future. Teeth will naturally darken over time and many enjoy the benefit of touchups every few months, or in time for special occasions like vacations and weddings. All that is necessary is some extra whitening gel that your dentist can provide.