is a common procedure in general dentistry but most especially in the field of cosmetic dentistry. Many people consider “white” teeth to be an attractive feature of a smile, offering a more youthful appearance, often taking “years” off of your age. Children's deciduous teeth are generally whiter than the adult teeth that follow. The adult teeth often increase in value as a person ages–that is to say, they become darker. This darkening can be due to changes in the mineral structure of the tooth, as the enamel becomes less porous. Teeth can also become stained by bacterial pigments, tobacco, sodas, etc.