Root canal treated teeth often tend to darken after a few years of treatment. When a front tooth is involved, aesthetics of even an otherwise flawless smile can be impaired. The natural color of such a tooth can easily be restored in most cases with the use of bleaching agents directly inside the dead tooth.
This will have to be repeated several times depending on the severity of the discoloration, until the final color is matching the adjacent teeth. When the required color is achieved then a new composite filling is done to restore the tooth permanently.