If you have a tooth that looks darker than other teeth, you may have experienced a traumatic injury in the past. Now days, lots of external whitening solutions are promoted but may not be the best solution for this type of injury. Internal bleaching, on the other hand, involves placing peroxide crystals inside of your tooth. In order to perform this type of whitening, a root canal must have been completed prior to starting treatment. Then a small hole will be made in the back of the tooth and any debris will be removed. Bleach crystals are placed inside of the tooth and the access sealed with a temporary filling material. This process can be repeated if the desired color has not been achieved. Since the tooth has already been root canal treated, this process is painless and you are able to eat and drink normally while the bleach is inside of the tooth.