How to Spot & Treat a Root Canal Infection

How to Spot & Treat a Root Canal Infection
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How to Spot & Treat a Root Canal InfectionClinical Content Reviewed by Dr. Jay Khorsandi, DDS
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Table of Contents

  1. Signs of a Root Canal Infection
  2. Will You Feel It Before You See It?
  3. What to Expect During a Root Canal
  4. Why Treat It Quickly?
  5. References
When the tooth’s hard outer layer (the enamel) is worn down by decay, it leaves the softer inner layer (the pulp) vulnerable to bacterial infection. The pulp contains all the live elements of a tooth – tissue, blood vessels, nerve endings, etc. – and when it gets severely infected, it needs to be removed to prevent the spread of the infection through your bloodstream to other parts of your body.
A root canal is a procedure in which infected pulp is removed, and the cavity is filled with a latex-based polymer filler, called gutta-percha.
signs of a root canal infection

In some instances, the bacterial infection persists after the procedure, and this is what we refer to as a root canal infection. It happens for a variety of reasons:

  • A narrow root canal is harder to clean and disinfect, and it may house bacteria.
  • Accessory canals can house bacteria and reinfect the tooth after the procedure.
  • If there is a delay in the placement of an artificial crown or permanent restoration, bacteria may get a chance to reinfect the tooth.
  • A crack or new cavity can instigate reinfection.

To spot it in time, you need to understand the warning signs and symptoms of a root canal infection.

How Do You Know if You Have a Root Canal Infection?

The most common signs of a root canal infection are pain, swelling, bad breath, discoloration and discharge.

Depending on the severity of the infection, pain caused by this kind of infection ranges from mild tenderness to a throbbing pain that lasts for hours and is essentially unbearable. This kind of pain is usually exacerbated by pressure (the weather) and temperature of food or liquids in your mouth (especially hot and cold beverages).
Swollen and Tender Tissue
If the tissue surrounding the tooth is swollen and painful when you apply pressure, it’s a sign that the tooth may be infected. Tissues are often redder than the surrounding tissue and feels warm to the touch. In severe cases, the swelling may be visible on your face and neck.
Sometimes, the swollen tissue releases greenish or yellowish pus. This is a definite sign of infection and requires immediate attention from a dental professional. Chances are if you are having discharge from your gums, your pain level is probably already off the charts.
Loose Tooth
If one of your primary (adult) teeth is loose for no apparent reason – no injury – there’s a strong likelihood that the tooth is infected or dying. You need to get this tooth looked at.
As the infection continues, the tooth may become discolored (yellow or dark brown), which is a sign that there is dead tissue in the root canal. Again, this is an indicate of a major issue that needs to be addressed by a dentist as soon as possible.
Bad Breath
Infected tissue has a bad smell, which can leave you with a bad taste in your mouth or bad breath, no matter how many times you brush your teeth.

Will You Feel an Infection Before You See It?

It’s certainly possible to feel a root canal infection before noticing it. It usually starts as a mild tenderness when you bite down too hard or sharp, temporary pain when you drink something that’s too hot or cold.

It’s easy to ignore because the pain doesn’t last too long. But, when it occurs along with other symptoms, it could be an early sign of root canal infection.

What to Expect During a Root Canal

Dentists recommend root canal retreatment as it is the only way to save the infected tooth.

  • First, your dentist will take an X-ray of the infected tooth to see how much necrotic (dead) tissue needs to be removed.
  • Before the procedure, you will receive local anesthesia to numb the affected area. Then, the dentist will place a protective shield around your mouth and gums.
  • Using a dental drill, they will penetrate through the enamel and pulp to access the root canal area. Then, they will clean out the necrotic tissue and all traces of the filler used previously. Once that is done, they will dry out the area.
  • The next step involves filling the cavity with amalgam or composite, a ‘bandage’ of sorts that protects the cavity while the root canal heals from the infection.
  • When it’s completely healed, the dentist may resort to placing a permanent crown over the tooth to prevent future infections. It may require them to carve away more enamel.

The Importance of Treating Your Infection Quickly

A root canal infection is like any other bacterial infection and will spread to the surrounding tissue if left unchecked. It can infect the gums, the surrounding teeth, and even facial tissues, so once you detect it, time is of the essence.

Keep in mind that the body is not equipped to deal with infections inside the teeth. A root canal infection won’t go away on its own and will likely persist and grow worse with time. The longer you wait, the more teeth it can potentially affect.

Catching it early makes it possible for your orthodontist to curb the infection before it spreads to the surrounding tissue. The most serious issue that doctors worry about related to infections is the development of sepsis, which is a toxic response to an infection. Sepsis can kill you.

In cases of severe root canal infection, the only feasible treatment may be extraction. In extreme cases, root canal infections will even spread into the bloodstream.

However, if the condition is diagnosed within the first few hours or days of infection, it’s quite possible to save the tooth and install measures to prevent reinfection. Visit your dentist as soon as you spot any signs of root canal infection to maximize your recovery chances.


Sepsis and Dental Infections. Sepsis Alliance. Date fetched: September 7, 2021.

Root canal treatment. Queensland Department of Health. Date fetched: September 7, 2021.

Root Canal Safety Talking Points: Information to share with patients concerned about the safety of root canal treatment. American Association of Endodontists. Date fetched: September 7, 2021.

Methods of Diagnosis and Treatment in Endodontics: A Systematic Review. Swedish Council on Health Technology Assessment. Date fetched: September 7, 2021.

Overview: Root canal treatment. National Health Service. Date fetched: September 7, 2021.

Disclaimer: This article is intended to promote understanding of and knowledge about general oral health topics. It is not intended to serve as dental or other professional health advice and is not intended to be used for diagnosis or treatment of any condition or symptom. You should consult a dentist or other qualified healthcare provider with any questions you may have regarding a medical condition or treatment.