I’ve had this question come up in discussions with dental writers and with patients who have a misconception about teeth bleaching. They understand that teeth tend to accumulate stains over the years. They absorb the pigments from coffee, highly pigmented fruits, wine, and other sources. Bleaching, they think, is a way to remove all those stains.

They’re only partly right. Yes, bleaching will remove those stains, but it will whiten even the natural pigment in your teeth. Let me illustrate this with a couple of stories.

When I went to dental school, I learned about shade guides. The most popular one was the Vita shade guide. Here is a picture of it:

It has a full spectrum of the range of shades a dentist is likely to encounter in natural teeth. When we needed a porcelain crown to match a patient’s other teeth, we could almost always find a shade in this guide that came pretty close to the patient’s natural tooth color.

In the 90’s, when teeth bleaching became popular, we started to have a problem with this shade guide. We would have people who needed porcelain crowns, and when we tried to find a shade that matched them, they would be “off the chart.” Their teeth would be much whiter than the whitest natural shade on the shade guide. In response, shade guide manufacturers developed new whiter shades. Ivoclar was the first manufacturer that I remember doing this, and our office purchased this four-shade guide and used it to communicate with dental laboratories. You can see that shade guide at the right.

Vita also updated their shade guide, and here is a picture of the current version, with what they call the “bleached extension” shades on the left:

Serious cosmetic dentists will, of course, use this amplified shade guide because they are frequently dealing with patients who have bleached their teeth. Often, regular family dentists will only use the original A1-D4 shade guide. This led to a problem with one patient who e-mailed me around 2005. She had bleached her teeth, and was now getting porcelain veneers on four front teeth. Not knowing how specialized cosmetic dentistry is, she chose a regular family dentist to do these veneers. For the shade, this dentist selected the whitest shade on his chart. When the veneers came back from the lab, they were noticeably darker than her teeth. The dentist assured her that by using the whitest cement the veneers would match her teeth. She wrote to me, “Alas, this was not the result: there is at least an entire shade (if not more) of difference between my porcelain veneers and my other teeth.” I answered her that unfortunately, her dentist used the classical shade guide, and the whitest shade on that guide could be considerably darker than bleached teeth. For the full story, see the page under “Cosmetic Dentistry Horror Stories” where I discuss her question, can you bleach porcelain veneers?

When my own children got all of their permanent teeth in, I let them bleach their teeth if they wanted to. Even though they weren’t old enough to have any accumulated stains, they were able to whiten their teeth significantly.

So how white can you get your teeth? The results of studies seem to show that the longer you bleach, the whiter they will become, and no one, to my knowledge, has found the limit. The rate of whitening decreases the longer someone uses the bleaching gel, and everyone will hit a point where they don’t want to do it anymore. Some people get them so white that they seem to glow.