The tooth has an outer layer called an enamel. How the natural teeth look is a result of the reflection of light by the enamel and the color of the dentin that lies beneath it. Not everyone has the same type and thickness of enamel on their teeth, as it is largely a matter of gene that gives each person a different kind of enamel. The thinner the enamel, the more of the dentin lying below is visible, giving off the discolored look on the teeth.

Here are some reasons that lead to discoloration of the tooth and thus leading to the need of tooth whitening:

• Chewing tobacco
• Smoking
• Drinking liquids that are dark in color, e.g. Cola, coffee, tea, wine
• Improper dental routine

Teeth also lose their luster and brightness due to aging, as the enamel wears off leading the dentin to start showing.

The dentist will first talk to you to understand your food habits and lifestyle and help ascertain the cause of teeth discoloration. This step is necessary as they can help identify the causes and ensure that you avoid the food and activities that lead to said discoloration.

Next, they would need to do a bit of dental groundwork, especially if there are cases of tooth decay and cavities, since these need to be filled before the teeth whitening work begins. If not addressed the whitening solution can pass through the crevices and into the cavity, which is not advisable. Also, in cases of receded gums, the visible portions of the tooth cannot be treated for discoloration with any whitening solution. Porcelain and ceramic crowns too cannot be whitened.