If you have a front tooth that’s discolored after you get a root canal, you can get its appearance restored through an internal tooth bleaching procedure. A root canal involves the removal of nerves inside the tooth root, which means that the dentin will no longer be ‘alive’. Over time, the dentin will darken, sometimes as a result of blood pigments that remain after the pulp is removed and sometimes because of the material used to fill the root canal.

Internal tooth bleaching is done using a bleaching agent called sodium perborate, which is mixed with sodium peroxide to accelerate color change. If the discoloration is severe, sodium perborate is mixed with 3% hydrogen peroxide solution. Endodontic bleaching involves placing the bleach in the hollowed out pulp chamber of the problematic tooth.

What you should be prepared to ask your dentist

In order to manage your expectations, you should be prepared to ask your dentist these questions:

  • What is the expected rate of success of using internal bleaching on my discolored tooth?
  • How closely with the resulting tooth color match my other teeth?
  • Will I need to get a crown or a veneer when the bleaching is completed?

The stages of internal (endodontic) tooth bleaching

Internal tooth bleaching is done in the following stages:

  1. X-ray examination 

Your dentist has to x-ray the discolored tooth to ensure that the root canal filling still holds intact and that it provides adequate sealing for the root. He/she also has to make sure that the underlying bone is healthy.

  1. Preparing an access cavity

The dentist will then make a small hole to access the pulp space. He/she will clean out debris from the space and remove any staining. Your dentist will also irrigate the canal that’s above the filling.

  1. Sealing (‘cervical’ seal)

The area above the root canal filling will be sealed so that the bleaching agent doesn’t come into contact with the root canal filling.

  1. Bleaching

The bleaching putty is then introduced into the pulp chamber after which it’s covered with a small amount of cotton pellet and temporarily sealed with adhesive. You will have to go through the same procedure every four days until the tooth is sufficiently bleached.

  1. Permanent sealing

Once the bleaching procedures are completed and your tooth is the color you desire, the dentin is sealed with a permanent filling and the access cavity restored with teeth-colored filling.

Internal bleaching is a less drastic and less involved procedure as compared to using veneers and crowns. However, it’s sometimes used together with veneers and crowns, as it’s possible for the discoloration to show through a veneer or crown. After your tooth is bleached, a crown or veneers can be used to strengthen it.

How internal bleaching compares to teeth whitening

Teeth whitening is performed on the surface of teeth and will not reach areas under the enamel. Internal bleaching reaches underneath the teeth, restoring your smile and improving oral health.

Care after internal bleaching

A tooth that has been bleached can still get discolored and you should therefore avoid habits and foods that can stain your teeth to ensure your tooth remains stain-free.