Root Canal Treatment

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Root Canals Stain Teeth
©Warren Goldswain/Shutterstock.com

Last week, Pam left a comment asking whether or not root canal treatment can darken a tooth.  I gave her a short answer, telling her that sometimes root canals can discolor teeth.

If you want to know about the four different ways that a root canal can darken your tooth, this article is for you.

4 Ways Getting a Root Canal Can Discolor or Stain Your Tooth

Pink Rubber Dental Dam1 – The tooth can get discolored if any pulp tissue is left inside the tooth.  If you’ve read this post about the anatomy of a tooth, then you know that the pulp is the center layer of the tooth.

It can be easy for a dentist to accidentally leave some pulp tissue inside of the tooth because sometimes the pulp isn’t all together in the middle of the tooth.  Sometimes there are little offshoots of pulp tissue in little tunnels that branch away from the main pulp chamber known as pulp horns.

The book Esthetic Dentistry by Aschheim states, “Elusive pulp horns and lateral extensions of the pulp chamber often remain untouched during routine endodontic access preparation…Careful removal of tissue and debris from these areas may help prevent subsequent tooth discoloration.”

If any pulp tissue is left inside of the tooth after the root canal is completed, it can decompose and eventually discolor the tooth.

How to fix discoloration caused by pulp tissue: Usually internal bleaching can remove any discoloration that was caused by pulp remnants left inside of the tooth.

2 – A tooth with a root canal get get discolored if root canal filling materials are left in the crown portion of the tooth.  When dentists do root canals, they remove the pulp tissue from the tooth (hopefully enough so that it doesn’t discolor the tooth – see above) and replace it with a liquid sealer and a solid rubber filling material called gutta percha.

This study showed that all root canal sealers can cause tooth discoloration when remnants of the sealer are left in the crown portion of the tooth.  Certain sealers may stain the tooth more than others.  Gutta percha is also believed to be able to discolor teeth.

Prevention is the best approach for this type of root canal discoloration.  The dentist can prevent this by removing any root canal filling materials that are in the crown portion of the tooth and keeping them isolated to the root portion of the tooth.

How to fix discoloration caused by root canal filling materials: Internal bleaching is the best method to remove this type of root canal discoloration.  However, if the staining was caused by a sealer with a high metal content, bleaching may not be extremely successful and if it is, the tooth may discolor again in the future.

3 – Medications that are put into the root canal can discolor a tooth with a root canal.  Sometimes dentists add certain medications when they do root canals to help increase the chances that the root canal will be successful.

The book Endodontics: Principles and Practice by Torabinejad says, “Several medicaments have the potential to cause internal discoloration of the dentin.  Phenolic or iodoform-based…medications, sealed in the root canal space, are in direct contact with dentin, sometimes for long periods, allowing for their penetration and oxidization.   These compounds have a tendency to discolor the dentin gradually.”

How to fix discoloration caused by root canal medications: A majority of root canal discoloration caused by medications can be reversed by simply bleaching the tooth.

4 – A tooth with a root canal can get discolored depending the material that is put inside of the crown.  If an amalgam (silver metal) filling is used to build the crown of the tooth back up after completion of the root canal, the amalgam filling can stain the tooth a dark gray color.

You can prevent this staining by asking your dentist to not use amalgam to fill any of your front teeth so that your smile remains aesthetically pleasing.

How to fix a discoloration in a tooth with a root canal caused by an amalgam filling:  Metallic discoloration caused by an amalgam filling is hard to remove, but some experts say that internal bleaching may work depending on how discolored the tooth is.  Sometimes, replacing the metal filling with a white composite filling can help gradually reduce the staining caused by the amalgam filling.

Conclusion

As you can see, there are a variety of ways that root canals can discolor your teeth, but they are usually reversible.

This doesn’t mean that root canals will always discolor your teeth.  I had a root canal on a tooth four years ago.  I had it filled with a white composite filling and it hasn’t discolored.

In fact, many times a root canal can turn a discolored tooth white again!

Do you have any comments or questions about tooth discoloration due to root canal treatment?  I’d love to hear what you have to say in the comments section below.  Thanks for reading!