What to do when a Root Canal Fails


Root Canal Fails

Understanding the next steps when a root canal fails is crucial for patients who have experienced this procedure. Root canal therapy, a widespread dental treatment, aims to preserve a tooth compromised by infection or decay through the removal of its affected nerve and pulp. Despite the generally high success rate of root canals, estimated at 86% to 98%, failures do occur. This article delves into why root canals fail, the indicators of such failures, and the effective treatments available. We’ll also provide expert insights and real-life patient experiences to help you navigate this situation more confidently.


Root canal failures arise from a variety of factors, such as:

  • Hidden Canal Branches: Complex dental anatomy often harbors unseen canal branches, eluding detection and treatment.
  • Root Cracks: Root fissures or fractures impede complete canal sealing, potentially causing reinfection and heightened sensitivity.
  • Dental Obstructions: Existing dental work (like another tooth, fillings, or improperly placed sealants) can restrict access to the affected canal.
  • Procedural Errors: Even skilled dentists might overlook a canal or postpone essential post-treatment steps like crown placement, leading to failure.

Understanding Responsibility in Root Canal Failures: While dentists strive for successful outcomes, root canal failure isn’t always attributable to their actions. Even with the best efforts, some treatments may not yield the desired result. It’s important to recognize this aspect and focus on maintaining rigorous oral hygiene to prevent future dental issues and potential root canal complications.

Root Canal Fails
Root Canal Fails

Real-life Example

Sarah’s Story: Sarah underwent a root canal on a molar, where the main canal was treated, but a hidden secondary canal went unnoticed. This oversight led to bacterial infection, resulting in discomfort and swelling. Upon her return, the dentist identified and treated the missed canal, effectively saving Sarah’s tooth. This case highlights the importance of thorough dental examinations and the potential for retreatment success.

By understanding the causes of root canal failure and seeking prompt treatment, patients like Sarah and John can address the issue and save their teeth. Maintaining proper oral care and regular dental check-ups can also help prevent root canal failure and ensure long-lasting dental health.


Post-root canal, vigilance for failure signs is essential. Early detection of these symptoms can lead to prompt intervention, enhancing the chances of preserving your tooth. Key indicators include:

  • Tooth sensitivity or pain when biting down: This could be a sign that the infection hasn’t been entirely cleared or that the tooth has been damaged during the procedure.
  • A pimple or boil on the gums: Also known as a dental abscess, this is often a sign of an ongoing infection in the tooth or gum tissue.
  • Tooth discoloration: If your tooth starts to darken after a root canal, it could be a sign that the tooth is dying due to a failed root canal.
  • Tenderness in the gum tissue near the site of the root canal: This could indicate that an infection is still present.
  • Pain in the treated tooth: Persistent pain after a root canal could be a sign that the procedure was not successful.
  • Abscesses filled with pus near the treated tooth: This is a clear sign of an ongoing infection.
  • Swelling of the face, neck, or gums around the affected tooth: This could indicate a spreading infection.

Real-life Example

Consider the case of Mike, a middle-aged man who recently underwent a root canal procedure. A few weeks after the treatment, Mike started experiencing severe pain when biting down on the treated tooth. He also noticed a small pimple-like bump on his gums near the tooth. Concerned, Mike returned to his dentist, who confirmed that the root canal had failed and an infection was still present. Mike was then referred to an endodontist for retreatment.


Facing a failed root canal can be daunting, but multiple treatment avenues exist. These options, tailored to individual cases, offer hope for recovery and dental health restoration. The best course of action will depend on the specific circumstances of your case, and your endodontist will be able to guide you through the decision-making process. Here are the main treatment options for a failed root canal:

  • Retreatment: This is often the first line of treatment when a root canal fails. The endodontist will reopen the affected tooth, remove the original filling, disinfect the canal, and reseal it. Retreatment has the highest success rate among the available options, and it’s a good choice if the cause of the failure can be easily addressed.
  • Apicoectomy: If retreatment isn’t possible or doesn’t resolve the issue, an apicoectomy may be recommended. In this surgical procedure, the endodontist partially or completely removes the tip of the root and applies a new seal. This can be effective in cases where the root canal anatomy is complex or inaccessible.
  • Tooth extraction: In some cases, the tooth may be so damaged that it cannot be saved. If this is the case, extraction may be necessary. After the tooth is removed, a dental implant can be used to replace it, helping to restore function and appearance.

Real-life Example

Lisa’s Journey Through Root Canal Retreat: Lisa’s case, involving her premolar, underscores the complexity of dental treatments. Months after her root canal, persistent pain led to the discovery of a missed canal branch, indicating failure. The subsequent referral to an endodontist and the successful retreatment not only resolved her discomfort but also preserved her tooth, showcasing the effectiveness of specialized dental care.

In conclusion, while root canal treatments are generally successful, failures can occur. Being aware of the symptoms and seeking prompt treatment from an endodontist can help address the issue and save your tooth.

What Are the Most Common Signs of a Failed Root Canal?

Common signs include persistent pain or discomfort in the treated tooth, swelling or tenderness in the gums around the tooth, the appearance of a pimple-like bump on the gums (dental abscess), tooth discoloration, and increased sensitivity to hot or cold temperatures.

Can a Tooth Be Saved After a Root Canal Failure?

Yes, in many cases, a tooth can be saved even after a root canal failure. Treatment options like retreatment, apicoectomy, or, in some cases, tooth extraction followed by dental implants or bridges can be effective in addressing the issue.

How Long After a Root Canal Can It Fail?

Root canal failure can occur shortly after the procedure or several years later. Early failures are often due to procedural complications, while later failures might result from new decay, fractures, or gum disease affecting the tooth.

What Causes a Root Canal to Fail?

Root canal failures can be caused by various factors, including complex root canal anatomy, undetected canal branches, procedural errors, cracks in the tooth, and recontamination of the tooth due to decay or gum disease.

Is Retreatment for a Failed Root Canal Painful?

Retreatment procedures are generally performed under local anesthesia, making them as painless as possible. Most patients report discomfort similar to or less than that of the initial root canal procedure. Your dentist or endodontist will take all necessary steps to ensure your comfort during the treatment.

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