Root canal therapy has an incredibly high success rate, often exceeding 95 percent. It is the gold standard for saving a tooth that has been severely damaged by decay or infection.

However, like any medical or dental procedure, there is a small chance that a root canal can fail.

At Medford Square Dentistry and Implant, we want our patients to be fully informed about their oral health. Understanding why a failure might happen and knowing that you have effective retreatment options can turn a stressful situation into a manageable one. If a tooth that previously had a root canal starts acting up, it does not necessarily mean the tooth is lost.

What Does Root Canal Failure Look Like?

A root canal failure typically occurs when the initial treatment did not eliminate the infection or when the tooth becomes re-contaminated. Symptoms can appear immediately after the procedure or even years later.

Common signs to watch for include:

• Persistent Pain: While some tenderness is normal for a few days after treatment, sharp or throbbing pain that lingers is a red flag.
• Swelling: Any swelling in the gums near the treated tooth or in the facial area suggests an active infection.
• Sensitivity to Pressure: If it hurts to bite down or even tap on the tooth, the area around the root may still be inflamed.
• Pimples on the Gums: A small, boil-like bump on the gum line, known as a fistula, is a sign that the body is trying to drain an abscess at the root tip.

Common Causes of Failure

There are several reasons why a tooth might not heal as expected. Most of these involve the complex internal anatomy of the tooth.

Hidden or Complex Canals

Teeth are not always simple structures. Some teeth, especially molars, can have narrow or curved canals that are difficult to detect. If a tiny branch of the canal is missed during the initial cleaning, bacteria can remain inside and eventually cause a new infection.

Delayed Permanent Restoration

After a root canal, the tooth is usually sealed with a temporary filling until a permanent crown can be placed. If you wait too long to get that crown, the temporary seal can leak. This allows bacteria from your saliva to seep back into the canal system and re-contaminate the tooth.

New Decay or Fractures

Even a perfectly treated tooth can fail if it is not cared for. If a new cavity develops under the edge of the crown or if the tooth sustains a hairline fracture, bacteria gain a new entryway into the root system.

What are the Options for Retreatment?

If a root canal fails, the first step is a thorough evaluation. We use advanced imaging to see exactly what is happening beneath the surface. From there, we typically have three main paths.

1. Endodontic Retreatment

This is the most common solution. We carefully remove the existing crown and the filling material that was placed during the first root canal. We then re-clean the canals, looking specifically for any missed branches or hidden anatomy. Once the infection is cleared, we reseal the tooth and place a new crown. This second chance is often all a tooth needs to heal permanently.

2. Apicoectomy

If the infection is located at the very tip of the root and cannot be reached through a standard retreatment, we may suggest an apicoectomy. This is a minor surgical procedure where we access the root tip through the gum tissue. We remove the infected tip, seal the end of the root, and allow the bone to heal around it.

3. Extraction and Replacement

In cases where the tooth is severely fractured or the bone support is too weak, saving the tooth might not be the best long-term option. In these instances, we may recommend removing the tooth and replacing it with a dental implant. An implant provides a highly durable and natural-looking solution that prevents future infections in that area.

Frequently Asked Questions

Q: Is retreatment more painful than the first root canal?

A: No. Just like your first procedure, we use local anesthesia to ensure the area is completely numb. You might feel some pressure, but you should not feel pain. The goal is to remove the source of your discomfort.

Q: How long does a retreatment take?

A: Because we have to remove old filling materials and perform a more detailed cleaning, retreatment often takes longer than the original procedure. It may require two separate visits to ensure the infection is completely gone before the final seal is placed.

Q: Can a tooth fail twice?

A: While it is possible, it is very rare that the retreatment is performed by an experienced professional using modern technology. We take every precaution to identify the exact cause of the first failure to ensure the second treatment is successful.

Q: Will insurance cover a second root canal on the same tooth?

A: Insurance policies vary. Some will cover a portion of the retreatment, while others have waiting periods. Our team at Medford Square Dentistry and Implant can help you navigate your benefits to understand your coverage.

Protecting Your Dental Investment

A failed root canal is a setback, but it is one that we can fix. The most important thing you can do is act quickly when you feel symptoms. Ignoring the pain will only allow the infection to spread, which can lead to bone loss or the loss of the tooth entirely.

If you are experiencing discomfort in a tooth that was previously treated, contact us today. We will help you explore your options and find the best way to get your oral health back on track.