I had a patient in the office today for non-vital bleaching and found myself explaining to her we call it walking bleach, because you walk around with it in your tooth. It was the classic case of a tooth that had been traumatized years earlier. As a result the pulp died and the tooth turned a dark yellow color. This patient had the good fortune that the tooth was totally unrequested prior to the endo so we made the decision to do a conservative access and walking bleach followed by a composite as the final.
Non-Vital bleaching can be an effective way to restore the esthetics of a tooth and avoid restoration as well as to correct tooth color prior to a final restoration to facilitate a great final esthetic result. Once the endo obturation is complete make sure that the gutta percha has been removed to the level of the crestal bone. Leaving gutta percha above this level can add an orange cast to the root which creates a shadow at the margin of a new all porcelain restoration. Non-vital bleaching is most commonly accomplished using Sodium Perborate. These white crystals are mixed in a 2:1 ration with either distilled water or hydrogen peroxide. Using hydrogen peroxide as the wetting agent has been shown to increase the effectiveness of the bleaching.
It is recommended to seal the tooth with a composite filling versus temporary filling material. This helps eliminate the risk of bacterial contamination of the root canal space and leaking of the bleaching agents into the mouth. First etch the internal surface of the access at the margin so we can bond in a temporary resin filling. Next mix the Sodium Perborate and water in a dappen dish, and then carry it to the tooth with an amalgam carrier. Use a condenser to fill the root canal space above the gutta percha. You can place a dry cotton pellet over the bleaching agent and then seal the final layer with a resin and cure. Active bleaching occurs in 3-7 days, and it may take 2-4 applications to completely correct the color of the tooth. Advise the patient to monitor the color and come when the tooth reaches the color of the adjacent teeth to avoid over bleaching.
As with everything we do there are risks and benefits. Non-vital bleaching has been associated with external resorption, although the exact mechanism has not been determined. The literature cites an incidence of external resorption following internal bleaching from as low as 3% to almost 14% when the tooth has also has a history of trauma.