What symptoms may indicate the need for a root canal?

A tooth that hurts to the touch, swelling at the root of a tooth, or a bump on your gum may indicate the need for a root canal. When a tooth abscesses and infection builds up at the root of the tooth, it presses on the nerves causing the tooth to hurt when touched. Swelling along the root of the tooth can also occur with the buildup of infection. Eventually the infection finds a place to drain causing a bump on your gum. If you have these symptoms, you should see your dentist for treatment for a root canal. Sometimes, there are no symptoms, which is why regular exams with x-rays are important. An x-ray can show abscessed teeth with no symptoms.

When the pulp (soft tissue inside your teeth containing blood vessels, nerves and connective tissue) becomes inflamed or diseased, root canal treatment is necessary. If the infected pulp is not removed, pain and swelling can result. Then, your tooth may have to be removed. 

The main symptom associated with a tooth needing root canal is pain. Others include and are not limited to swelling, feeling hot or fevered on face, sensitivity to hot or cold, pain upon chewing, discharge around the tooth. So there are many signs that may cause someone to think that they may need to have root canal done on a tooth, but the diagnosis and treatment needs to be done by a dentist who can first do the proper testing of the tooth including x-rays and determining if the tooth is a good candidate for a root canal.

Todd A. Welch, DMD

Depending on the cause, symptoms can be numerous and varied:

  • Sharp, acute and intense pain, which is difficult to pinpoint
  • Sharp pain when biting down on your tooth or on food
  • Lingering pain after eating hot or cold foods
  • Dull ache and pressure
  • Tenderness (accompanied by swelling) in the nearby gums
Romesh Nalliah

Common symptoms that indicate the need for a root canal treatment include the following:

  1. spontaneous pain with no specific trigger
  2. pain response to hot and cold that lasts several minutes
  3. pain on biting that lasts several minutes
  4. long lasting, throbbing pain with sharp exacerbations 
Divyang Patel

There can be a variety of symptoms a patient may experience when a root canal treatment is needed. Some of them can be throbbing pain, sensitive to temperature changes, pain while lying down, and swelling at the gum line on the affected tooth or darkening of the tooth.

There may or may not be pain on a tooth that needs root canal treatment (RCT). It depends on the condition of the nerve. When there is pain associated with a tooth that needs RCT it is most often sharp and shooting pain that keeps a patient up at night. Pain that lingers with hot and/or cold is also an indication that the tooth may need RCT. A tooth that has experienced trauma may discolor in time which also indicates the need for RCT. It is best to see your dentist to have your teeth evaluated rather than wait for pain to tell you to go to the dentist. Early prevention and early detection can help to avoid a painful experience.   

A root canal is necessary if the pulp (nerve) inside the tooth is damaged to the point that it has died or no longer has the ability to repair or heal itself. The root canal procedure, in simplistic terms, is designed to remove the damaged or infected nerve tissue so that the tooth iteslf can be preserved.

Teeth that need root canal treatment can exhibit a wide range of symptoms from extreme throbbing pain to absolutely no pain at all. Let's explore some of the more common symptoms and what they mean:

Sensitivity -- Most people will experience tooth sensitivity in their lifetime. Every one of us has had a bite of cold ice cream and gotten that "jolt" in the tooth. This sudden and short-lived sensation is very common and lets us know that the nerve inside the tooth is alive and well. Exposed root surfaces, habitual grinding of teeth, recent dental work, and even aggressive tooth brushing can cause sensitivity. Although it can be quite a nuisance, tooth sensitivity in general is not cause for worry and does not indicate the need for a root canal. Modifications of habits and application of topical desensitizers can help reduce or eliminate tooth sensitivity in most cases.

Irreversible Pulpitis -- When the soft tissue inside the tooth (the nerve) becomes irritated, an inflammatory process occurs just like anywhere else in your body. The soft tissue starts to swell. However, encased in hard tooth structure, there is no place for the swelling to go. Instead, pressure builds up inside the tooth and the result is a dull throbbing pain. Dull throbbing pain that is spontaneous or that persists for a length of time after a stimulus such as cold water is applied to the tooth may indicate that the nerve is dying and that the tooth will require a root canal.

Apical Periodontitis -- When the nerve inside the tooth has died and becomes infected, the bacterial byproducts make their way to the end of the root and begin to leak out. The body detects this and mounts an inflammatory response on the outside of the tooth. Similar to what occurred in the irreversible pulpitis, swelling occurs outside the tooth with no place to go. Pressure builds up as pus forms and it produces a dull ache that can be very severe. Pain from pressing or chewing on the tooth is not too different from pressing on a bruise and is highly indicative of the need for a root canal. 

Accurate diagnosis, however, can only be made through x-rays combined with clinical exam. 
Lucia Yau, DDS
Sensitivities to cold that lasts for minutes and does not go away easily may indicate irreversible pulpitis, a condition that needs root canal treatment. In addition, pus or "pimple" like growth in the gum next to the tooth often indicates the tooth has an infection that needs root canal treatment.
Nicole Holland
A root canal may also be needed following traumatic injury to a tooth, e.g., fall, sports injury, etc. A root canal is needed when the nerve tissue in the tooth is irreversibly damaged, which can happen due to injury. Although a root canal may not be needed immediately following dental trauma, a discoloration or darkening of the tooth over time often indicates a dying nerve that may require root canal treatment. The tooth in question should be evaluated by your dentist for proper treatment immediately following the trauma and periodically reevaluated thereafter.
You might need a root canal if you have a tooth that's become infected with bacteria. An infected or decaying tooth gives off plenty of signals that you should see your dentist. Your tooth may feel more sensitive to hot or cold foods, you may develop a toothache, or your face, gums, or neck might swell up.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.