How does teeth whitening work?

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There are many different products and procedures to whiten your teeth. However, at the end of the day all of them, no matter if we speak about in-office or over-the-counter solutions, work in one of two ways:

1. Physical action

Physical action procedures remove the superficial stains of our teeth. By rubbing abrasive materials against your teeth these products aim to break the microscopic film of foreign material that accumulates on top of the teeth’s natural enamel layer changing its color or generating stains.

This procedure is very similar to sanding an old table to remove the layers of old paint and dust that might have accumulated over the years to bring the natural color of the original wood back to the surface.

Powders are the best example of physical teeth whiteners as we can actually see the grains that act like the sanding paper against our teeth. Whitening toothpastes work the same way by mixing microscopic grains of polishing material with the cream of the paste so that it will rub against our teeth when we brush them.

Some of this physical action methods might also combine some chemicals to help break that layer of foreign material.

2. Bleaching procedures

Bleaching procedures’ goal is both to remove both deep and surface stains as well as change your natural tooth color to a brighter shade of white.

Most bleaching procedures rely on an active agent that will generate a chemical reaction and penetrate the enamel layer. This chemical agent is usually Carbamide Peroxide which is applied in different concentrations (usually between 10% and 24%) depending on the amount of stains that need to be removed or the color change that wants to be achieved.

Bleaching procedures can be performed at the dentist’s office or at home with an over-the-counter whitening kit. Depending on the kit chosen the application method might vary, from those that are applied with your finger like a cream to those that are poured inside a dental tray to ensure a continuous contact between the gel and your teeth. Some of this kits also come with a blue LED light which function is to accelerate the chemical reaction of the bleaching agent.


It’s important to understand that physical procedures will only return our teeth to its original color at best, whereas bleaching solutions will allow us to change the color of our teeth to a lighter shade of white than our original color. Even the physical action procedures which contain chemical won’t make our teeth whiter than they originally were as those chemicals are only meant to help break the film of foreign material that forms on top of the enamel layer over time.