Whether you get your teeth whitening done at the dentist or you use an at-home method, it’s common that you experience tooth sensitivity after treatments.  There are reasons that this happens and knowing them will show you how you can be treating sensitivity issues to make for a better, less painful teeth whitening experience.

The tooth sensitivity that comes with teeth whitening is caused by your personal genetics, the stability of the bleaching process used, and the acidic reaction of the chemicals involved.  Most of the sensitivity comes from the changes made to the teeth themselves during the bleaching process.

As the figure shows, your teeth have millions of microscopic dentinal tubules, which extend from the pulp (nerve) out to the surface of your teeth.  These tubes are filled with fluid and movement of that fluid is what causes sensitivity.  Normally, minerals contained in your saliva plug the tops of these tubes (as shown), but bleaching usually dissolves those plugs, opening the tubules.

This creates tooth sensitivity as the fluids inside them moves.  Most liquids like bleach solution gels cannot penetrate into the tubules.  However, when the fluid inside them escapes and leaves a void, this void is often very painful.  Most of the time, tooth sensitivity is merely the movement of fluid as some escapes before new plugs are formed.

Some people, genetically, are more predisposed to this tooth sensitivity than others: especially fair-haired people and those with larger, thicker teeth.

The plugs dissolving are not due to the bleach itself, but the acidity of the bleach instead.  Usually, higher-quality gels and treatments will not cause much tooth sensitivity as they are formulated to be as acidically neutral as possible.  Lower-cost gels and bleaches, however, do not go through the processes required for thsi and are usually slightly alkaline or acidic.  This is the main cause of tooth sensitivity.

Desensitizing agents are commonly used in treating sensitivity and are available in toothpastes, as after-appliques for whitening, or are in the whitening gels themselves.  Finally, newer desensitizers include oxalates and HEMA-based products for restoring the plugs.

Tooth sensitivity during and after teeth whitening is not a big issue if you understand how to be treating sensitivity issues before they become painful.