Congratulations! You’ve survived a root canal procedure. Contrary to popular belief, root canal treatment isn’t nearly as painful as its reputation makes it out to be. Even though it’s a routine treatment, complications can, unfortunately, arise sometimes. If you have a poorly done root canal, failed root canal, or other kind of root canal complication, you might need to have the procedure redone in order to save the tooth.

The Root Canal Procedure: What to Expect

The root that holds a tooth in place contains blood vessels and nerves called the pulp. Sometimes the pulp can become infected (usually because of an untreated cavity), causing pain and swelling. If the problem is too deep to be taken care of with a normal filling, the dentist will recommend an endodontic treatment—what most call a root canal procedure.

1. During the procedure, a dentist or endodontist (a root canal specialist) drills a hole into the tooth in order to access the root of the tooth. 
2. The dental professional cleans the infected tissue out of the pulp chamber.
3. Now that empty space is filled in with a rubber-like material and capped off with a temporary crown. 
4. Finally, a custom-fitted crown that resembles the original tooth is sealed in place.

The dentist will take precautions to ensure that all of the infection has been thoroughly removed from the root of the tooth. The dental professional may apply an antibiotic to the empty root before they fill it. A dentist may also prescribe antibiotics for the patient to take in the days after the procedure.

Can Root Canals Go Bad?

Yes, root canals can go bad. But the success rate for root canals is about 95%—meaning that, in the vast majority of cases, the root canal procedure is successful and the patient’s tooth will be pain-free and healthy once again. With good oral care, a successful root canal can last at least 10 years, and even longer when a crown is put in place. But there are some cases where the tooth doesn’t heal, in which situation the root canal goes bad. Research has shown that there are a few different factors that may result in a failed root canal procedure.

Signs of Root Canal Failure

Some infection remains. Sometimes the canals in teeth are curved or extremely small. In complex cases like these, the dentist might miss some areas of infection. After the root canal is done and the tooth is sealed up, the bacteria left behind will continue to grow and cause the infection to get worse. The fact that a root canal procedure removes blood vessels complicates matters; no blood supply means no chance for the body’s natural immune system to fight off infection. This can easily lead to more root canal complications.

New bacteria entering. Even if the dentist does a thorough job of cleaning the root, bacteria may still get in. Delays in sealing the tooth can give saliva a chance to contaminate the area. Bacteria can also slip past an ill-fitting temporary crown—another way in which a root canal can fail.

Crown wearing down. Patients who have a successful root canal procedure may still develop problems later on. Over time, normal wear and tear from biting and chewing, or a habit like teeth grinding, can take a toll. Dental crowns can crack, or the inner seal used to fill the canal might start to erode. In these scenarios, or if the tooth suffers a trauma, bacteria can be reintroduced into the root canal. This is not due to a failed root canal per se, but it does require revisiting the procedure.

Signs of a Failed Root Canal

A patient can expect to experience some discomfort after a root canal. The pain should go away within a few days and is usually manageable with over-the-counter acetaminophen or ibuprofen. If the tooth with the root canal hurts and the pain is severe or lasts several days, you might have a poorly done root canal. Look out for signs your root canal has failed:

• Swelling might occur inside the mouth or the face.
• In severe cases, there may be discharge coming from the area of the infected tooth. This could indicate an abscess.
• Persistent pain from pressure built up in the tooth.
• Tooth discoloration.
• The gum tissue where the root canal was performed is tender. 

Symptoms of a failed or poorly done root canal might not become apparent right away. If the reinfection develops gradually, or if it is due to a new situation like a cracked crown, it could be months or even years before a patient notices anything is wrong.

Pain, swelling, and especially discharge after a root canal procedure should be addressed as soon as possible. An appointment with a dentist or endodontist should be made right away, before the infection has a chance to spread further.

Options for Treating Root Canal Complications

There are three basic options for a failed root canal. 

Option #1: Extraction

The most drastic treatment for a root canal that goes bad is extraction. If the tooth is too badly damaged, a dentist may recommend removal to stop the infection from spreading. After pulling the tooth, options such as an implant, bridge, or dentures can be considered.

Dentists and endodontists will always save teeth if they can. After a poorly done root canal, this usually means retreatment—in other words, doing the procedure over. Retreatment is the most common and the most successful remedy to a failed root canal.

Option #2: Retreatment

Basic retreatment is the second option and involves taking the crown off the tooth and removing the material used to fill in the root. Then, the dentist or endodontist will clean out the pulp chamber again, refill it, and recap the tooth with a new crown. Some of the latest endodontic treatments use new technology such as ultrasonic waves to clean and remove infected tissue. Chances are that retreatment of a root canal done just a few years ago will utilize newer, more effective methods.

Option #3: Apicoectomy (aka Root-End Surgery)

Endodontic surgery may be the best option in some cases, if the infection can’t be reached through normal retreatment. An apicoectomy, or root-end surgery, involves an incision at the tip of the root. This allows the canal to be cleaned and filled from both ends.

Don’t Ignore a Poorly Done Root Canal

Like other dental issues, such as having cavities filled, the longer you wait to fix a poorly done root canal, the more painful and expensive it will be. Untreated infections can spread to surrounding teeth and gums. In severe cases, bacteria can cause serious sinus infections or even bone loss in the jaw.

If you suspect a root canal has been done poorly or incorrectly, it is important to get a second opinion. Use our online search tool to find another dentist in the area for that second opinion.

 

This post has been updated and was originally published on May 27, 2019.