Internal bleaching is used to lighten a single tooth that is discolored and has had prior root canal therapy. These teeth have typically suffered some degree of trauma previously, which led to internal bleeding and subsequent discoloration. Since the source of staining originated from within the tooth, a special internal bleaching technique must be performed.External bleaching using trays or lasers will have no effect on this variation of tooth staining.
The discolored tooth is accessed from the back. Oxidizing agents are placed within the coronal tooth structure and left in place for 1-2 weeks. This process can be repeated to eventually achieve the desired outcome of lightening the tooth. A permanent restoration such as a filling will be required after the internal bleaching procedure.
Below depicts a successful before and after internal bleaching of an actual patient's teeth.