Why Does My Tooth Still Hurt After A Root Canal?

Post Root Canal Pain

When you have a root canal procedure done to solve a toothache, your dentist removes the nerve from the roots of your tooth before sealing and restoring it. It may seem strange then, that after the root canal is performed, you might still experience tooth pain and tenderness. How is this possible when your tooth doesn’t have nerves?

Going back to why you needed the root canal in the first place- your tooth was either badly decayed or the pulp of the tooth may have become infected. When a tooth becomes sick due to decay or infection, the ligaments surrounding the tooth may experience some swelling and inflammation. This is the cause of your tooth pain. It takes some time after a root canal procedure is done for the tissues to return to normal and for the pain to go away.

This isn’t the only cause of post root canal pain. Other causes include:

  • Gum Tissue Trauma

Your dentist will need to isolate your tooth for the root canal treatment. This is done by using a rubber dam and placing it around the tooth. A metal clamp is used to keep this rubber sheet in place and the prongs of this tool may traumatize (bruise, cut, pinch) the gum surrounding the tooth.

This may cause some minor tenderness which should disappear on its own in a day or so. To help speed up healing, you can use a salt-water rinse.


  • Infection in the bone

Even with a successful root canal procedure– the removal of the infected tissues within a tooth and its proper sealing and filling, bacteria can still linger in the bone around the tooth. This can cause some inflammation and pain.

Your immune system should be able to deal with this minor infection over the course of a few days. You can request the prescription of some antibiotics to speed up the process.


  • Cleaning beyond the end of the root

A root canal entails your dentist cleaning out the decayed parts of your tooth, infected soft tissues, and ultimately, the nerve/s within it. They use an instrument called a file during the cleaning process. It is possible that while cleaning, the file went beyond the end of the root. Tissue damaged by this take some time to heal, and while it is still healing, you will experience some soreness.


  • The sealer was pushed out the end of the tooth

After your dentist or endodontist cleans out the decayed tissue and the nerve endings of your tooth, a material called a sealer is used to seal the inside of the tooth. There are cases where the sealer may have been pushed a little too far and come out the end of the tooth (apex). This can possibly irritate the tissue there and cause some tenderness.

The disintegration of the sealer material into the tissue can cause tissue destruction. This can affect the healing process of the tooth. However, most cases end with the tissues eventually tolerating the sealer.

In some rare cases, a small air bubble may have been pushed through the apex of the tooth. This causes some pressure and pain.

For both cases, the pain will subside on its own sooner or later.


  • Oversized filling/ crown

After the root canal, your dentist has to put in a filling material to seal up the tooth. There are cases when this filling ends up a bit too tall or the crown is a bit too big. When you bite down on your teeth, this tall filling or oversized crown will receive the brunt of the force instead of the weight of the bite being distributed evenly among your teeth. This will cause the tooth to become sore.

This has an easy solution, but you will have to schedule another visit to your dentist so that he can buff the excess filling until it is the correct and comfortable height or adjust the size of the crown.

Even after the proper adjustments are made, the tooth pain may still linger for around three to five days.


  • Phantom pain

This is a very uncommon cause of post root canal pain. This “phantom pain” is caused when the nerve leading to the tooth that received root canal treatment is still attached to the tooth nerve even if the nerve endings in the tooth’s roots have been removed. Like an amputee who feels “phantom pain” in a limb that has been removed, the nerve will feel like the tooth is infected or sick even when it is not.

This pain is not triggered or affected by biting down or exposure to hot or cold foods. The pain can be described by patients as a throbbing or aching in a tooth that has been treated. Over time, the pain may spread to wider areas.

The injection of a local anesthetic may or may not relieve the tooth pain. Since the cause of the pain cannot really be identified, this can be confusing and frustrating for both the patient and the dentist.

Most of the time, tricyclic antidepressants are used to treat this condition. These medications are used for their pain relieving properties and not their antidepressant effects.


  • Missed Root/ Canal

Each tooth can have several canals. Some of them, especially in molars, can be hard to detect. It is possible that your dentist may have missed one of these canals. Even if the tooth is sealed, the leftover space leaves room for bacteria to grow, especially if this root was infected.

If your tooth pain is caused by a left over nerve, your tooth will be sensitive to hot and cold. On the other hand, if the pain is caused by a bacterial infection, your tooth will be sensitive to pressure.

A repeat root canal treatment will have to be scheduled with your dentist or endodontist to solve this problem.