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Failed Root Canal: Causes and Treatments

Millions of people across the world experience tooth pain every day. For some of us, it’s minor and easily ignored. Ignoring tooth pain now can lead to bigger problems down the road, such as an infection or an abscess.

Ongoing pain and sensitivity after a root canal can signify that you’re experiencing a failed root canal. Though rare, it does happen occasionally. Root canals have a high success rate. According to the Cleveland Clinic, over 15 million root canals are performed annually in the U.S., with a success rate of over 90%.

But what happens if the root canal fails? This article will teach you about the causes, symptoms, and possible options after a failed root canal.

What Is a Root Canal and Why Your Dentist Recommended You Get One

There are many parts to a single tooth, including the crown, root, and pulp. Sometimes, the root or pulp can become infected. Once an infection has set in, a root canal is the treatment of choice.

During a root canal, the canals of your tooth are cleaned to remove any infection. A sealant is added to prevent new infections from developing. You may also be prescribed antibiotics before and after the procedure to help eliminate any bacteria present.

Root canals are used to treat:

  • Chronic tooth pain
  • Pain when biting or chewing
  • Sensitivity to hot or cold
  • An infection with symptoms such as fever, swollen gums, swollen lymph nodes
  • Dental trauma such as a chipped or cracked tooth
  • A cavity that was left untreated

Why Do Root Canals Fail

Finding out the root canal failed would disappoint anyone. A failed root canal treatment can be devasting. After all, you’ve suffered from pain and discomfort in the affected tooth while waiting for your treatment, not to mention the cost involved.

It’s important to remember that over 90% of procedures are successful and will last a lifetime. A root canal can fail if the infection isn’t properly treated or the tooth is re-infected, even years after the initial treatment.

Is Your Dentist Responsible for A Failed Root Canal Surgery?

It depends. If your dentist fails to perform the procedure with an acceptable standard of care, the treatment will fail. In this case, the practitioner could be guilty of malpractice.

However, in most cases, a root canal will fail for other reasons. Dentists are held to a high standard of care, as are most medical practitioners, so while it’s possible, it’s unlikely your dentist is responsible for the treatment failure.

Some causes of failed root canals are:

  • Poor dental hygiene
  • Not following post-treatment instructions
  • Failure to properly clean the tooth before and after the root canal procedure
  • Using a low-quality or low-sterility sealant material
  • Inadequate removal of infected tissue
  • Leaving bacteria or other debris behind
  • Infection
  • Poor healing
  • Fracture of the tooth
  • Perforation of the sinus cavity
  • Traumatic dental injuries

Symptoms of root canal failure are the same as those that lead to the root canal in the first place and include pain, swelling, fever, drainage or pus, sore throat, and a foul taste in your mouth.

See your dentist immediately if you experience these symptoms after a root canal. There are many options to address treatment failure, but the first step is to see the dentist or endodontist for a diagnosis.

It’s important to note that a root canal could fail many years after the initial procedure, in addition to problems occurring immediately after the procedure.

How is a Failed Root Canal Treated

Since the most common cause of a failed root canal is an infection, the first step is often treating the infection with antibiotics and/or re-treating the root.

The infection may be due to bacteria or viruses, and it can prevent the wound from healing properly. Other common causes of a failed root canal include poor oral hygiene, trauma to the mouth, gum disease, and age-related changes in the mouth.

If you have a failed root canal, there are a few options your dentist may recommend. If the failure was caused by infection, antibiotics might be used to eliminate the bacteria before any other treatment.

Retreatment of The Tooth

A repeat root canal may be necessary to clear the root and pulp system infection. In this case, the previous sealant is removed, and the roots are cleaned and resealed. Sometimes, a person could have a more complex root system or an extra canal – if these canals were missed during the initial procedure, the treated tooth would often become infected again, leading to failure.


A minor surgery called an apicoectomy may be used to treat infection within the root or pulp of the tooth. In this procedure, a tiny incision is made in the gums to access the root and pulp to address the infection. After the procedure, a sealant is used to prevent any future complications. Occasionally, a graft can be used to repair the bone if the bone is compromised.


As a last resort, tooth extraction may be performed. In the event that an extraction is needed, a dental implant is used to replace the tooth.

To prevent failure of your root canal, practice good oral hygiene, follow all after-care instructions from your dentist, and complete all medications and follow-ups.

See Your Dentist or Endodontist ASAP if You Suspect Your Root Canal Has Failed

A failed root canal can be a painful and costly experience. In most cases, the dentist is not responsible for the failed treatment, but there are many possible causes. See your dentist immediately if you experience any of the symptoms of a failed root canal. There are many options available to address a failed root canal treatment.

Frequently Asked Questions

Can a failed root canal cause headaches?

Tooth pain will often radiate to the rest of the face and head, leading to headaches. In addition, an infection can cause fever, chills, and headaches.

Can a failed root canal cause sinus problems?

Infection or abscess from a failed root canal can spread to involve your sinuses. Also, an abscess can cause pressure on the sinuses. If you have sinus problems after your root canal, follow up with your dentist.

Can a failed root canal cause swollen lymph nodes?

The lymph nodes play an important role in your immune system. Many of these nodes are present in the head and neck, so if your root canal has failed and become infected, it’s possible your lymph nodes will become swollen.


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