Discoloration: Prevention and Correction
WHEN DOING ROOT CANAL treatments on anterior teeth, especially pulpotomies and pulpectomies, make sure that you do not leave any blood or a bloody cotton pellet inside the chamber. If the tooth is hyperemic, try to control it as quickly as possible. If you do not, this will often stain the tooth, and the patient will be unhappy to see the drastic discoloration that can happen overnight.
Internal bleaching, also called the walking bleach technique, can be an easy, conservative way to satisfy a patient’s esthetic need. However, unlike veneers and crowns, internal bleaching may not provide a permanent solution to a discoloration condition. The discoloration may reoccur slightly in the future, so it is important to inform the patient that the internal bleaching may need to be repeated in the future.
Before starting the procedure, it is important to use a shade guide to record the original shade of the tooth and take a photo. As an endodontist, I ask you to please also take a periapical x-ray to check the quality of the root canal treatment. Once these are done, dry the gingiva and apply a layer of Vaseline so that the gingiva does not burn. Place the rubber dam and clean out the access. If needed, use a slow speed round bur (size 6–8) to clean out the facial interior surface and expose clean dentin. Remove a little bit of the gutta-percha so that it is 1–2 mm below the CEJ. Place a 2–3 mm layer of glass ionomer, Cavit, or IRM around the CEJ right on top of the gutta-percha. This barrier will help prevent external resorption. (Do not use composite. The bonding agent can easily get all over and seal up the dentinal tubules, which will not allow the bleaching agent to work properly. Composite, unlike glass ionomer, also has shrinkage properties, and bleaching agents can leak through the CEJ.) Mix sodium perborate powder and hydrogen peroxide to a wet sand consistency. Pack the pulp chamber with this paste and place IRM or Cavit on top. A cotton pellet is not needed because it often does not even fit in this area.
Following the procedure, I like to see the patient in about a week to check the color. If a lighter shade is needed, this procedure may have to be repeated right away in order to achieve it. In Figure 1, the patient had a very minor discoloration and wanted to try internal bleaching. After just one week, the tooth became lighter and the patient liked the result (Figure 2). For patients with a darker discoloration, the procedure will often take two or three tries.
On a side note, patients often ask if there is any pulpal damage when doing external bleaching. There is no pulpal damage, but minor inflammation can occur, which is reversible. It is especially common to experience post-op sensitivity if there are any leaking restorations, cracks, or gingival recession areas.