Retreating a Root Canal: When Do You Need to Redo a Root Canal

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Teeth that have undergone a root canal treatment are expected to last a lifetime.

Occasionally, the healing doesn’t occur properly and may show signs of pain and disease after months and years of treatment. In this case, you’d need an additional endodontic re-root canal therapy to get rid of the symptoms appearing. 

The extra treatment will help save your tooth from extraction, which, if extracted, can give rise to other problems, like tooth shifting, malalignment, improper bite, and poor smile. 

Let’s talk about the basics of this treatment so that you’re fully in the know about the procedure …

What Is Root Canal Retreatment? 

When there’s a failed root canal, your dentist will perform a re-root canal procedure in an attempt to save the tooth; otherwise, you will need a tooth extraction.

Root canal therapy removes all the nerves within the tooth to make it a painless mouth structure. Pain serves as a motivator for a retreatment option. If your tooth is still painful after a complete root canal therapy, an immediate tooth inspection and investigation is warranted.

Why do you need endodontic retreatment? 

According to the American Association of Endodontists, a root canal-treated tooth may not heal exactly the way expected after the first root canal due to the following reasons: 

Primary Causes 

Several reasons halt the healing of root canal-treated teeth, including: 

  • Missed narrow canals leave back the bacteria and the debris within the tooth.
  • Canals are not negotiated properly to their full length, specifically with curved canals. 
  • Complicated canal anatomy that was missed in the initial treatment
  • Delayed capping of the tooth caused the salivary debris and bacteria to leach into the canal, causing re-infection. 
  • The leaky restoration does not offer a complete barrier to the tooth.
Pain Root Canal

Several secondary problems often jeopardize the initial problem, even when the tooth was successfully treated. Like:

Secondary Causes 

  • Secondary tooth decay makes the tooth barrier leaky while exposing the root canal filling material to bacterial contents
  • A broken crown or other restoration leading to infection 
  • Fractured tooth
  • A tooth infection that does not heal after months of treatment appears with symptoms.

Signs That You May Need Root Canal Retreatment

Persistent pain or discomfort

Ideally, your root canal-treated tooth shouldn’t be painful once the treatment is done. If you still feel the pain in the same tooth, there might be something wrong inside and /or outside the tooth. You may also feel sensitivity to hot and cold foods.

This is likely due to the leftover nerves within the tooth that are hypersensitive to the signals. Sometimes, you may also feel discomfort upon chewing from the root canal-treated side. This emphasizes an underlying tooth abscess which is due to the tooth infection.

Swelling or tenderness in the gums

Swelling around the treated tooth on the gums suggests tooth infection. You may feel pain in touching the tooth or when you apply pressure to the gums. You may also notice pimples like bumps or fistulas around the tooth on the gums.

Presence of infection or abscess

If you’re experiencing pus discharge, foul taste, or odor in your mouth, you might be suffering from an active infection. There are visible abscesses or pus-filled sacs near the root tips on the X-rays. You may also have a general feeling of lethargy or fever. 

The Process of Retreating a Root Canal

Initial assessment and diagnosis

Root Canal Treatment

Primarily, an endodontist specializing in retreatments must deal with the case. Your endodontist will rule out the other causes of pain. Sometimes, your adjacent teeth are painful, and you believe the tooth that has undergone root canal treatment is causing it. 

Your dentist will thoroughly examine your mouth, aided by magnification and light.

He will also discuss the tooth to determine its periodontal and periapical status. Multiple angulated radiographs or CBCT will be taken as an obligatory investigation to find out the root cause of the problem.

Four options will be provided to you before proceeding to the next step: 

  • Do nothing, 
  • Extract the tooth,
  • Non-surgical retreatment, or
  • Surgical retreatment. 

Removal of previous filling materials

To gain access to the tooth root canals, your dentist will remove the dental crown or the dental fillings. This will give access to the root canal filling material, which will also be removed to negotiate the canals. Sometimes, the post and core must be disassembled to get straight access to the canals.

The removal is done carefully to prevent the removal of excessive tooth structure. With more tooth removal, the tooth structure will weaken, making it difficult for it to bear the forces applied to the tooth after the treatment, leading to tooth fracture. 

Cleaning and disinfecting the root canal

This process involves the removal of gutta-percha from the tooth root canals. Normally, K-files are used to negotiate the canals during the initial root canal treatment; this process consists of using H files. These files allow easy removal of packed toot canal filling material followed by disinfection with 2.5% sodium hypochlorite for thorough tooth cleaning.

This step aims to remove all the dead pulp structure, bacteria, and debris from the canals to their full length to make the tooth painless for the patient. 

Filling and sealing the root canal

Once the canals are negotiated and shaped to their complete length, they are refilled with gutta-percha and a sealant. A cone-fit radiograph is taken at this step to confirm whether the full-length seal is achieved. 

X-Ray Negative of Tooth Endodontic

Restoring the tooth’s structure

The coronal portion of the tooth will then be restored with a tooth-filling material, like composite resin or amalgam, as needed. However, a post and core must restore a compromised tooth structure. It will hold the crown in place if a significant amount of tooth structure has been removed in step 2. 

What is a Surgical Root Canal Retreatment Procedure? 

When non-surgical treatment alone would not resolve the tooth problem, surgical treatment is recommended. These are used to locate small tooth fractures and hidden canals that are hard to detect on multiple X-rays. There are different types of endodontic surgeries other than the retreatment surgery. These include:

1) Apicoectomy (Root End Resection) 
2) Hemisection 
3) Bicuspidization
4) Intentional Reimplantation

Potential Outcomes of Root Canal Retreatment

Outcomes of root canal treatment vary from person to person.

Successful resolution of symptoms

The primary goal of root canal and re-root canal treatment is to eliminate all the symptoms like pain and swelling. This allows patients to return to their normal eating and hygiene maintenance habits, which were previously missed due to the symptoms.

Possibility of continued discomfort

In very few cases, even after the retreat, the discomfort or pain continues. This may be due to an existing infection which requires antibiotic therapy to call off the pain. Continued pain requires further evaluation. 

Alternative treatment options if retreatment is not successful

If the non-surgical re-root canal does not work for you, you may need to go for a surgical retreatment option or may go for extraction. After extraction, you may go for tooth replacement options like dental implants, dental bridges, or single-tooth dentures. 

Aftercare and Recovery

Tips for managing posttreatment discomfort

Discomfort and pain can be managed with over-the-counter pain-relieving medications like acetaminophen or ibuprofen.

over-the-counter pain-relieving medications

Applying cold compresses on the outer side of your cheek can overcome the pain as well. You must stick to a soft diet and avoid eating from the affected site unless the root cause of the problem has been detected and resolved.

Follow-up appointments with your dentist or endodontist are mandatory to monitor the health of your tooth. Your dentist will carry out some investigations like X-rays to evaluate healing every three months and up to 2 years. 

Maintaining oral hygiene after root canal retreatment

Regular brushing and flossing will save your tooth from acquiring secondary caries which can potentially infect your root canal. Consider using an antimicrobial mouthwash with chlorhexidine to prevent infection. Regular dental checkups are mandatory for early diagnosis of oral problems


How much will re-root canal treatment cost? 

As the process is more complex than the basic root canal treatment, it will cost you more than the first one. Although the cost varies on the complexity of the procedure, the procedure is complex itself. Your endodontist will first go about removing all the existing tooth and root canal filling material to find out the missing root canals within the unusual root canal anatomy. The process will take more time as well.

Is retreatment the right choice for you? 

It is exactly like better than nothing. Saving a tooth is better than getting it extracted because no other tooth alternative will exactly mimic your natural tooth. Retreated teeth can function well for years or may stay functional for a lifetime.

Success depends on a lot of factors and with any dental or medical procedure, it is not guaranteed. However, it is advised to save the tooth rather than get it extracted.

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