Signs of a Root Canal Infection

What is a root canal infection, and what are the causes and signs of this condition? How are they treated, and how can these dental emergencies be prevented? Our Edmonton dentists answer these questions and more.

What is a root canal infection?

Our teeth are made of layers. Enamel is the hard, outer surface that protects the dentin (inner layer). The dentin is a porous, almost sponge-like tissue that protects the nerves. If decay penetrates it, the pulp at the centre of the tooth can become infected. 

Tooth pulp contains blood vessels, nerves and cells that keep the tooth healthy and allow it to grow. If this pulp is infected, injured or damaged, your dentist can remove the pulp to save the tooth. 

Root canal infections can occur initially when decay reaches the inner tooth pulp. A root canal procedure is designed to remove the infection and save the tooth, but there's a small risk of a tooth becoming infected, or an infection persisting, even after you've had a root canal. 

What are the symptoms of a root canal infection?

It's normal to feel discomfort, tenderness and even a little pain in the few days following a root canal procedure. Many patients experience mild pain the week after. 

But if severe pain continues to plague you for more than a week after the procedure, or if the pain is just as comfortable or more intense than before the procedure was performed, we recommend seeing your dentist. 

Here are some common symptoms of a root canal infection:

  • Unbearable tooth pain when eating, applying pressure or exposing the tooth to extreme temperatures
  • Lingering or pulsing toothache
  • Dental abscess
  • A bad taste in your mouth or bad breath 
  • Gum tenderness and swelling
  • Swollen, red or warm tissue
  • Tenderness or discomfort in swollen tissue
  • Green, yellow or discolored pus discharge

What causes root canal infections?

Many potential factors can contribute to a root canal infection, including:

  • Tooth decay
  • A chip or crack in the tooth 
  • A fractured tooth root 
  • Damaged tooth pulp (with or without damage to the tooth's exterior)
  • Repeated dental procedures

If you have had a root canal procedure, a tooth can be infected following the operation. Reasons for this include:

  • Your tooth may have curved or narrow canals that weren't completely cleaned and disinfected during the procedure. 
  • The shape of your root canals are very complicated, infected areas may not be detected during the first procedure, which may result in infected tissue or areas being left behind, leading to ongoing issues. 
  • Your tooth may have extra, accessory canals where bacteria can linger and reinfect the tooth. 
  • The placement of the crown or permanent restoration is delayed following treatment, leading to harmful bacteria getting lodged in your tooth. 
  • A new cavity can develop in the tooth after treatment, or become cracked or damaged, leading to a new root canal infection. 

When should I see my dentist?

Unfortunately, root canal infections don't resolve themselves. The longer you wait to see your dentist for treatment, the worse the infection can become. A root canal infection can spread, destroy your tooth and lead to dental emergencies and even compromise your overall health, potentially resulting in brain abscess, bone tissue infection, sepsis and other life-threatening conditions. 

It's also possible for each of the causes of root canal infection mentioned above to occur without symptoms, which means that seeking treatment as soon as an issue develops or is suspected is critical to your health. 

How are root canal infections treated?

A root canal is a relatively simple procedure that takes one or two visits to a dentist. 

First, the dentist will remove the affected tissue before cleaning and sealing the interior of the tooth. Finally, the missing tooth structure is replaced with a dental filling. 

If there was extensive tooth decay, your dentist may recommend having a dental crown placed to strengthen and protect the tooth from fracture. 

How can I prevent a root canal infection?

There are several measures you can take to prevent a root canal infection, both initially and after the procedure.


  • Brush and floss at least twice a day. 
  • See your dentist for dental cleanings at least twice a year to have decay, infections or other oral health issues caught early, and to keep your teeth in good health. 
  • Avoid especially hard or crunchy food and candy, especially if your teeth are weak or you have dental restorations. 
  • Avoid acidic foods and drinks since they cause enamel erosion and expose your teeth to sugar. 
  • Do not chew ice, as this can contribute to cracks and fractures, leading to damaged tooth pulp. 
  • Wear sports guards or night guards as recommended by your dentist to protect your teeth from damage. 

After a Root Canal Procedure

In addition to taking the steps above, here are things you can do after a root canal procedure to prevent a root canal infection from recurring: 

  • Rinse with a gentle antiseptic mouthwash for the first few days following the procedure. 
  • Take over-the-counter pain medication if you experience any pain after treatment.
  • Return to your dentist for a final crown or permanent restoration as soon as possible. This will protect your tooth by sealing the root canal from bacteria.

At any point, if you notice early signs of infection or experience persistent pain or discomfort in your mouth, see your dentist for an examination and treatment. Early detection is key to correcting the issue and preventing long-term health complications. 

Are you experiencing tooth pain or other concerning symptoms? Contact our Edmonton dentists right away. We can examine the problem and recommend treatment options.

Have a dental emergency in Edmonton? We're here on weekends and after hours to help.

Dental emergencies always happen when you least expect them. Our friendly and experienced dental team is on call to assist you when you need us most.

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