How to Recognize the Symptoms of a Failed Root Canal

Root canals have a sinister reputation and the odd horror story about failed operations can convince people that routine side effects are actually the symptoms of something much worse. Failed root canals occur when the number of the tooth's canals are not spotted or removed or when infection creeps back in to the tooth pulp. They're very infrequent, but you can recognize them through certain specific signs.

Notice excessive tooth pain that does not fade over time. A certain amount of ache usually accompanies a root canal--lingering after-effects of the condition it corrected--but if the pain persists over time or grows worse, it may signal that the root canal has failed.

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Look for a tenderness to the tooth's bite or sensitivity while eating. A post-op root canal always involves a little tenderness, which is why dentists recommend eating soft foods after the procedure. However, sensitivity that lingers or that may flare up again after time has passed may suggest symptoms that your dentist should know about.

Recognize a lack of temperature sensitivity in the tooth. Our teeth tend to respond to extremes in temperature, such as easting ice cream or very hot soup. If the tooth involved in the root canal doesn't reflect those sensitivities, something might be wrong.

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Examine your gums around the tooth for swelling or discoloration. Inflamed gums are often the most prominent sign of a failed root canal, as they may mean that the bacteria and decay are continuing to irritate the surrounding tissue.

Watch for the development of a new infection, especially fluid from the tooth. If bacteria seeps back in to the part of the tooth that the dentist cleaned out during the root canal, it can create problems of this nature, resulting in a need to return to the dentist to correct the problem.

Follow up with x-rays from your dentist. While many of these symptoms may suggest a failed root canal, the best way to know for sure is to let your dentist take a new series of x-rays. Generally, changes will appear from one set of x-rays to the next if the root canal has failed.


The best way to recognize the symptoms of a failed root canal is simply to remain in close contact with your dentist. She should be keeping track of your development after the procedure and will know if something goes wrong.


Many symptoms of a failed root canal resemble simple side effects from a successful root canal. Keep track of any symptoms you encounter, but don't panic.