1. Persistent pain Persistent tooth pain is one of the signs that you may need a root canal. The pain in your tooth might bother you all the time, or it might go away from time to time but always return.
You may feel the pain deep in the bone of your tooth. Or you may feel referred pain in your face, jaw, or in your other teeth.

2. Sensitivity to heat and cold Does your tooth hurt when you eat warm food or when you drink a cup of coffee? Or perhaps your tooth feels sensitive when you eat ice cream or drink an icy-cold glass of water.
The sensitivity could feel like a dull ache or a sharp pain. You may need a root canal if this pain lingers for an extended period of time, even when you stop eating or drinking.

3. Tooth discoloration An infection in the pulp of your tooth can cause your tooth to become discolored. Trauma to the tooth or the breakdown of the internal tissue can damage the roots and give the tooth a grayish-black appearance.

4. Swollen gums Swollen gums near the painful tooth can be a sign of an issue that requires a root canal. The swelling may come and go. It may be tender when you touch it, or it may not be painful to the touch.

5. Pain when you eat or touch the tooth If your tooth is sensitive when you touch it or when you eat, it could indicate severe tooth decay or nerve damage, which may need to be treated with a root canal. This is especially the case if the sensitivity persists over time and doesn’t go away when you stop eating.

6. A chipped or cracked tooth If you’ve chipped or cracked your tooth in an accident, in a contact sport, or by chewing on something hard, bacteria can set in and lead to inflammation and infection.
Even if you injure a tooth, but it doesn’t chip or crack, the injury may still damage the nerves of the tooth. The nerve can become inflamed and cause pain and sensitivity, which may require root canal treatment.

7. Tooth mobility When your tooth is infected, it may feel looser. This can be caused by other factors besides pulpal necrosis (nerve death), but it can be a sign that a root canal is necessary.