Advantages :
People typically have their teeth whitened to improve their appearance. Whiter teeth are associated with youth, beauty and a healthier lifestyle. You will find that you tend to smile more often and are less self-conscious. In addition, a whiter smile tends to minimize the effect of facial wrinkles, giving way to a more youthful and energetic appearance.

Whitening toothpaste can remove a stain that is on the outside of the teeth. Dentists call this extrinsic staining. However, whitening toothpaste and professional dental cleanings will not change the color or intrinsic staining of the teeth.  That is why bleaching is so popular.

Bleaching is much cheaper than crowns or veneers and research indicates that it is completely effective in more than 90% of people.

Disadvantages :
Some people experience discomfort from wearing the mouth guard. Your mouth should adjust in time but if you suspect that there is a problem with the fit of your mouth tray, call your dentist's office. It is possible to make small adjustments that would minimize or eliminate any discomfort.

Although bleaching is very effective, there can be short term disadvantages, such as sore gums or teeth from the bleach. This will disappear when the treatment is discontinued. Some individuals are more chemically sensitive. If you have had problems with this in the past, inform your cosmetic dentist so that you can be tested for sensitivity to the solution.

Despite all the recent advances in bleaching, there are times when it is not possible to whiten a person’s teeth, either because there are large fillings, or veneers or crowns in place. Bleaching does not lighten artificial materials such as resins, silicants, or porcelains. Certain drugs taken in childhood, tetracyclines for instance, can leave dark colors that cannot be changed by chemical bleaching. In these cases, porcelain veneers or crowns can be used. They do have the advantage that teeth can be reshaped and repositioned in a very easy way, and the color change is permanent.

There are also times when bleaching is not considered the best choice. In cases of severe discoloration veneers or crowns may be the superior choice. Teeth darkened with the color of yellow, brown or orange respond better to lightening. If you have very sensitive teeth, periodontal disease, or teeth with worn enamel, your dentist may discourage bleaching.

No one can really predict how much lighter your teeth will become as every case is different. The success rate depends upon the type of stain involved and your compliance.