How does teeth whitening work?

This is covered briefly in our Cosmetic Dentistry section, but here we will go into more detail of 

the specific chemicals, processes, and interactions with your teeth that occur during a standard 

teeth whitening procedure.

There are two main choices you have when choosing to get your teeth whitened. You can do it 

at home, or have it done professionally by a dentist. At­home treatments come in three forms:

1. Semi­opaque strips that stick to the teeth

2. Whitening trays filled with a cleaning solution

3. Brush on gels

There are some advantages to doing it yourself at home, such as decreased cost, or not having 

to schedule an appointment during your busy week. But there are some disadvantages as well. 

The amount of time you have to spend to get the same level of whitening done professionally 

add up pretty quickly. The at­home whitening procedures range from a week of use to a month 

of use, and beyond. If you aren’t looking to add one more thing to your daily regimen, then 

getting the job done at a dentists office is a wise choice. 

Now let us discuss the typical chemical mixtures that are used in teeth whitening, both in at-
home treatments, and in those performed in dental offices. Hydrogen peroxide is the basis of 

chemicals that are used to clean teeth. This is because it is chemically unstable and readily 

produces reactive oxygen. When this oxygen is released in an oxidizing form it targets the 

particles on the surface of the teeth that are the cause of staining or yellowing. Carbamide 

peroxide operates under the same concept except for the addition of urea(carbamide). This 

addition allows the peroxide to oxidize longer on the surface of the teeth. The longer the 

peroxide is on the teeth, the better job it can do in attacking the cause of discoloration.

The reason this peroxide doesn’t hurt your teeth is because your enamel is essentially 

composed of a layer of hardened minerals. These minerals cannot be affected by the peroxide. 

But within that structure of minerals there are organic compounds which are susceptible to 

staining. The peroxide targets those compounds, in effect, bleaching them so that they no 

longer have any pigment. This lack of pigment is the magic behind teeth whitening. 

At­home products:

● The strips have a gel on them which contains 10% carbamide peroxide gel or less

● The active ingredient that does all of the whitening in a tray system is usually a 6­16% 

solution of carbamide peroxide in a gel form (approximately equal to 3.4­7% hydrogen 


● The brush on gels use the same chemical in about a 6% solution

In­office solutions:

● Dental offices typically use a solution of 35%­45% hydrogen peroxide

● They reason they don’t use carbamide peroxide is that along with the hydrogen peroxide 

mixture, they use either heat, UV light, or both to enable the peroxide to work longer at 

targeting aforementioned organic compounds within the enamel of your teeth.