Today, the bleaching of nonvital, discolored teeth is a low-risk routine treatment for improving esthetics. When a tooth undergoes trauma, blood vessels are ruptured and red blood cells break down to produce a black pigment that results in tooth darkening. These factors responsible for discolorations are, in the majority of cases, located in the pulp chamber, causing dentin to darken from its innermost portion. However, external factors, such as absorption of artificial dyes from the diet and from tobacco can also contribute to tooth darkening.

A tooth that has suffered trauma and/or pulp death can be bleached from the inside once root canal therapy has been completed. A special peroxide solution is placed by the endodontist inside the pulp chamber and the tooth is sealed. The tooth is checked in several days for shade lightening. The tooth may need to have several bleach changes to achieve the desired shade, however; the final tooth shade cannot be guaranteed. A thorough knowledge of the etiology of discoloration is also important to planning treatment and establishing a prognosis. Discoloration caused by restorative materials(fillings) offers a problematic prognosis. Also, the younger the teeth, the easier they are to bleach, because of their greater permeability. Another important aspect is the period of time for which the tooth has been darkened; the more recent the discoloration, the easier it will be to remove. Sometimes internal and external bleaching techniques must be combined to achieve the desired result.