What to do when a Root Canal Fails


Root Canal Fails

Root canal treatment is a common dental procedure aimed at saving a natural tooth by removing infected or inflamed pulp from the inner chamber and root canals. While root canals have a high success rate, ranging from 86% to 98%, there are instances where the treatment may fail, leading to persistent or recurring symptoms.

If you’ve undergone a root canal and are experiencing discomfort, swelling, or other concerning signs, it’s crucial to understand the potential causes and available options. This comprehensive guide will delve into the reasons behind root canal failures, the symptoms to watch out for, and the various treatment approaches to restore your oral health.

Understanding Root Canal Failure

Before exploring the solutions, it’s essential to grasp the underlying causes that can lead to a failed root canal. Some of the common reasons include:

Missed Canals

One of the primary reasons for root canal failure is the presence of untreated or missed root canals during the initial procedure. Teeth can have complex anatomies with multiple canals, and if even one canal is overlooked or inadequately cleaned and sealed, it can harbor residual bacteria, leading to reinfection.

Delayed Crown Placement

After a root canal, it’s crucial to have a permanent restoration, such as a crown, placed on the treated tooth within a reasonable timeframe. Delaying the placement of the crown can allow bacteria to re-enter the tooth, compromising the success of the treatment.

Fractures or Cracks

Undetected fractures or cracks in the tooth can also contribute to root canal failure. These tiny openings can provide a pathway for bacteria to infiltrate the tooth, leading to persistent or recurring infections.

Salivary Contamination

During the root canal procedure, it’s essential to maintain a sterile environment. If saliva or other contaminants enter the tooth, it can introduce bacteria and compromise the treatment’s success.

Complex Anatomy

Some individuals may have particularly narrow, curved, or complex root canal systems, making it challenging to thoroughly clean and seal all areas during the initial treatment. These anatomical complexities can leave behind residual bacteria, leading to potential failure.

Symptoms of a Failed Root Canal

Recognizing the signs of a failed root canal is crucial for seeking prompt treatment and preventing further complications. Common symptoms to watch out for include:

  • Persistent or recurring pain: If you experience persistent or recurring pain in the treated tooth or surrounding area, it may indicate a failed root canal.
  • Swelling or tenderness: Swelling or tenderness in the gums or jaw near the treated tooth can be a sign of an ongoing infection or inflammation.
  • Tooth discoloration: A discolored or darkened tooth may suggest a failed root canal, as the tooth’s blood supply has been compromised.
  • Pimple or abscess on the gums: The formation of a pimple or abscess on the gums near the treated tooth is a clear indication of an infection that needs immediate attention.
  • Sensitivity to hot or cold temperatures: If the treated tooth becomes sensitive to hot or cold temperatures, it may signify a problem with the root canal treatment.

It’s important to note that some discomfort or sensitivity immediately after the procedure is normal and should subside within a few days. However, if the symptoms persist or worsen over time, it’s advisable to seek professional dental care.

Treatment Options for a Failed Root Canal

If you suspect a failed root canal, it’s crucial to consult with an endodontist (a dental specialist in root canal treatment) or your general dentist. They will evaluate your condition and recommend the most appropriate course of action. Here are some common treatment options:

Root Canal Retreatment

In many cases, a root canal retreatment (also known as endodontic retreatment) can be performed to address the failure. During this procedure, the endodontist will reopen the tooth, remove the previous root canal filling material, and thoroughly clean and disinfect the root canals. Any missed canals or residual infections will be addressed, and the canals will be refilled and sealed with new materials.

Root canal retreatment has a high success rate, ranging from 75% to 88%, making it a viable option for saving the natural tooth. However, the complexity and cost of the procedure may vary depending on the specific case and the expertise of the endodontist.

Apicoectomy (Root-End Surgery)

In some cases, when a root canal retreatment is not possible or has failed, an apicoectomy (also known as root-end surgery) may be recommended. This surgical procedure involves removing the infected or inflamed portion of the root tip and sealing the remaining root with a biocompatible material.

Apicoectomies are typically performed by endodontists and can be an effective solution for resolving persistent infections or anatomical complexities that cannot be addressed through retreatment alone.

Tooth Extraction and Replacement

If the root canal failure cannot be resolved through retreatment or surgery, or if the tooth is severely damaged or compromised, tooth extraction may be the only remaining option. In such cases, the extracted tooth can be replaced with a dental implant, bridge, or partial denture to restore function and aesthetics.

While tooth extraction may seem like a drastic measure, it can sometimes be the most appropriate solution to prevent further complications and preserve overall oral health.

Prevention and Maintenance

Preventing root canal failure is always preferable to undergoing additional treatments. Here are some tips to help maintain the success of your root canal treatment:

  • Follow post-operative instructions: Adhere to your dentist’s or endodontist’s instructions for proper care and maintenance after the root canal procedure. This may include avoiding certain foods, taking prescribed medications, and practicing good oral hygiene.
  • Maintain regular dental check-ups: Regular dental check-ups and professional cleanings can help detect any potential issues early on, allowing for prompt intervention and preventing further complications.
  • Practice good oral hygiene: Brushing twice a day, flossing regularly, and using an antimicrobial mouthwash can help prevent the buildup of bacteria and reduce the risk of reinfection.
  • Avoid excessive force on the treated tooth: Be mindful of activities that may put excessive force or pressure on the treated tooth, as this can lead to fractures or cracks, compromising the root canal’s success.
  • Consider a permanent restoration: If a permanent restoration, such as a crown, was not placed immediately after the root canal, discuss the option with your dentist to provide additional protection and prevent reinfection.

By following these preventive measures and maintaining open communication with your dental professionals, you can increase the chances of long-term success for your root canal treatment.


Root canal failure, while not uncommon, can be a frustrating and concerning experience. However, by understanding the potential causes, recognizing the symptoms, and exploring the available treatment options, you can take proactive steps to restore your oral health.

Remember, seeking prompt professional care from an endodontist or your general dentist is crucial when you suspect a failed root canal. With their expertise and advanced techniques, they can evaluate your situation and recommend the most appropriate course of action, whether it’s a retreatment, surgery, or alternative solutions.

By prioritizing prevention through good oral hygiene practices and regular dental check-ups, you can increase the chances of successful root canal treatment and maintain a healthy, functional smile for years to come.

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?

Complex root canal anatomy, undetected canal branches, procedural errors, tooth cracks, and recontamination of the tooth as a result of decay or gum disease are just a few causes of root canal failures.

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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