Root canals are a pretty common dental procedure. According to the American Association of Endodontists, over 15 million root canals are done every year in the United States alone.

But should you be concerned about a root canal infection? And are there any possible complications after a root canal you should know about?

Let’s get into how to recognize a root canal infection, what causes them, and how they’re treated.

Teeth aren’t solid all the way through — they’re made up of layers. The hard, outer surface of a tooth is called enamel. The inner layer is called dentin and is a porous, almost sponge-like tissue. At the center of each tooth is a collection of soft tissue called pulp.

The pulp contains the nerves and blood vessels that allow the tooth to grow. It’s full of cells called odontoblasts that keep the tooth healthy.

A root canal removes the pulp of a tooth that’s been infected or damaged by tooth decay or other injuries. Root canals can save teeth and are considered very safe.

Root canal infections aren’t common, but there’s a small chance of a tooth becoming infected even after a root canal is performed.

A little pain immediately after a root canal procedure is normal. You may have discomfort and tenderness that will last a few days after the procedure. You might have mild pain for a week after.

See your dentist if you continue to feel intense pain for more than a week after the procedure, especially if the pain still feels just as uncomfortable or worse than before the procedure was done.

Sometimes, you can get a delayed root canal infection on a tooth that’s pain-free for some time. A tooth that’s been treated with a root canal may not heal fully, and could become painful or diseased months or even years after treatment.

Signs that warrant a return trip to the dentist

Here are some common signs and symptoms of a root canal infection that mean you should schedule another visit to your dentist:

  • pain or discomfort ranging from mild tenderness to unbearable pain, especially when you apply pressure from eating or pressing on the tooth, or expose the tooth to extreme temperatures
  • pus discharge that’s greenish, yellowish, or otherwise discolored
  • red, warm, swollen tissue near the tooth, especially the gums under or around the tooth — in some cases, swelling can affect your face and neck, too
  • tenderness or discomfort in swollen tissue, especially when you touch or apply pressure to it
  • a bad taste in your mouth or a bad smell to your breath from infected tissue

Like any other infection, a root canal infection can spread to surrounding tissue in the mouth, including other teeth, gums, and tissue in the cheeks and face.

The infection won’t go away until it’s treated, and the longer you wait, the farther it can spread.

How far the infection spreads depends on how soon you get it treated after you start noticing symptoms. If you seek treatment hours or a couple of days after the infection starts, the spread can be minimized to the tooth itself or the surrounding teeth and tissues.

A root canal infection that’s left untreated can spread far beyond the tooth. In some cases, the infection can spread to the jaw, the face, and even into the bloodstream.

There are many reasons why a tooth can have an infection after a root canal. These include:

  • The shape of your root canals can be very complicated and areas of infection may go undetected in the first procedure.
  • Your tooth could have narrow or curved canals that weren’t fully cleaned and disinfected during the root canal.
  • Your tooth may also have extra, accessory canals that could be housing bacteria which may reinfect a tooth.
  • If the placement of the crown or permanent restoration is delayed following treatment, it could allow harmful bacteria back into your tooth.
  • Your tooth may get a new cavity after treatment, or become cracked or damaged, leading to a new root canal infection.

To treat a root canal infection, a root canal retreatment may be recommended to give your tooth a second chance. This retreatment is similar to the first root canal procedure.

In retreatment, your dentist or root canal specialist will typically do the following:

  1. Look for infected or dead (necrotic) tissue around the area of the root canal and take an X-ray.
  2. Numb the area around the affected tooth using local anesthesia.
  3. Place a protective barrier around the tooth to protect your gums and mouth.
  4. Use a dental drill to get through the filling and enamel to the pulp and root canal area.
  5. Clean out the area where the tissue is infected or dead, and remove old root filler material or medicine that may have been in the root.
  6. Dry out the area, then fill up the newly cleaned space with a safe, latex-based polymer filler (gutta-percha).
  7. Use filling material, such as amalgam or composite, to protect the tooth and allow it to heal from the infection.
  8. If necessary, carve away some of the outer enamel and place a permanent crown over the tooth to protect it from future infections.

There are several things you can do to help prevent a root canal infection, which involves taking care of your teeth after the procedure:

  • Brush and floss at least twice a day.
  • Use a gentle, antiseptic mouthwash for the first few days after a root canal. Use it as often as you’d like afterward, too.
  • Use an over-the-counter pain medication like ibuprofen for soreness after treatment.
  • Return to your dentist for a final crown or permanent restoration as soon as possible. This will seal the root canal from bacteria and protect your tooth.
  • Get dental cleanings at least twice a year to keep your teeth generally healthy and catch decay or infections early.
  • See your dentist right away if you notice any early signs of infection.

Root canals do NOT cause cancer

The documentary Root Cause released in 2018 follows the story of Australian filmmaker Frazer Bailey as he tries to determine the cause of his fatigue and depression. He believes a root canal he got when he was younger may have caused his symptoms. He even goes so far as to suggest that there’s a direct link between root canals and breast cancer in women.

No causal link has ever been found between root canals and cancer.

The American Dental Association (ADA), American Association of Endodontists (AAE), and American Association of Dental Research (AADR) have all released public statements warning that these false claims spread dangerous misinformation and may harm people who avoid getting root canals because of them.

Healthline

Root canal infections are rare, but possible. Keep an eye on any early signs of an infection after you get a root canal procedure done.

If you suspect your root canal has become infected, see your dentist as soon as possible to get it treated.