How can we deal with this? If you have a dark tooth that’s caused by an inadequate root canal treatment, the first thing to do is to replace the root canal treatment, disinfect and remove all the bacteria.
The staining outside the teeth will resolve partially by removing the bacteria. If you cut back the root canal and seal it off, and leave a cavity within the tooth, we can seal in a bleaching agent called sodium perborate.
This can be sealed in for five days or two weeks. And over this time, the dark pigments are oxidized and destroyed. Another way of doing that is to leave the back of the tooth open with adequate seal and wear a bleaching tray. This can happen very quickly, say in a day or two.
But one of the common ways to do this is to place sodium perborate within the tooth and it will all happen over two weeks.