Failed Root Canal Symptoms


Root canal therapy is a minimally invasive intervention that decreases pain, preserves a patient’s natural tooth, and heals quickly on its own. Millions of root canals are performed every year, and the vast majority of patients are satisfied with the treatment and outcome of this safe procedure. 

However, as in all medical and dental procedures, there’s a slight risk of root canal therapy failure. When this happens, it’s important to recognize the signs, symptoms, and causes. Fortunately, endodontists (specialists who treat root canals) can mediate a failed root canal with retreatment and surgical options. Let’s take a closer look.

Root Canal Basics

To understand why and how root canal therapy can go wrong, it’s important to know why you needed the procedure in the first place. To start, each of your teeth contains a soft tissue called pulp beneath the shiny white enamel that’s visible externally. Extending deep into your gums, this pulp tissue is enclosed within the “root canal” itself — and contains blood vessels and connective tissue that helped your teeth grow when you were a child.

In cases of injury or decay, bacteria can get inside the tooth’s root canal and cause infection and inflammation. When this happens, root canal therapy is performed — an endodontist cleans the pulp (and any infection) from the root canal, fills the canal with a rubber-like material, and seals the space off to prevent further infection.

Initially, root canal therapy is generally necessary when tooth trauma, injury, or decay has exposed the soft pulp within the “root canal” of the tooth. Once exposed, the pulp is vulnerable to bacteria, which causes infection and inflammation. As the infection progresses and spreads in this nerve-rich tissue, it can cause severe pain and swelling. Additionally, the infection can weaken the surrounding tissue and lead to damage to your jawbone and gums — eventually leading to tooth loss.

During an initial root canal, your dentist or endodontist accesses the soft inner tissue of the tooth through the crown of your tooth. Then, they remove the infected pulp, disinfect the area, and seal it to prevent further infection. Often, though you retain your original tooth, the practitioner places a crown over the area to protect it further.

Reasons why Root Canal Therapy Fails

Days, weeks, months, or even years after root canal therapy, a patient can discover that their initial root canal didn’t heal properly. Or, a recent injury or decay can compromise the root canal area once again. In the majority of cases, one of these issues causes root canal failure:

  • Inner seal breakdown. Recall that when the pulp is removed, a seal is placed to protect the sensitive area from further infection. If this inner seal breaks down, the tooth is once again vulnerable to bacteria and can become re-infected.
  • Dental crown breakdown. When the crown that protects the vulnerable tooth is placed too late after the procedure, bacteria can re-enter. This is also possible if the crown breaks or is cracked by an injury. 
  • Failure to clean the canal. Sometimes, the canals of the tooth are narrow, curved, or complicated. In other cases, the original dental x-rays didn’t catch cracks or crevices in the tissue that could harbor bacteria. If the canals weren’t properly cleaned, the infection can easily recur and spread.
  • Decay or injury. In some cases, the root canal becomes compromised due to a new tooth injury or tooth decay that once again exposes the tooth’s sensitive tissue to infection. 

Signs of Root Canal Therapy Failure

Whether your root canal was performed months or even years ago, you may be feeling that something isn’t quite right. Perhaps you’re experiencing pain that comes and goes near the affected tooth. Or maybe you’ve noticed that you’re suddenly more sensitive to heat and cold than before.

In many ways, signs and symptoms of root canal failure are similar to the sensations that may have motivated you to seek the procedure in the first place. When root canal therapy heals like normal, the patient will usually experience a drastic reduction in pain. A failed root canal, however, will result in the same symptoms that highlighted the need for a root canal in the first place. Pay special attention to any of the following signs of root canal failure:

  • Pain. In a root canal that heals properly, pain should dissipate normally after only a few days. However, in the case that bacteria have re-entered the canal, you will likely experience severe pain in the infected tooth.
  • Swelling. As the infection takes hold, you will often experience swelling as well.
  • Discharge. In some cases, you will experience discharge from the affected tooth. This could indicate that an abscess has formed due to the infection.
  • Increased sensitivity. In some cases, this could mean you are more sensitive to heat or cold; for example, you might find it unbearable to eat ice cream or sip hot soup. In other cases, you might just be more sensitive to any pressure — like when you eat or press teeth together.

  • Boil or pimple on jaw. If you’ve noticed a boil or pimple on your jaw that just won’t go away, you body might have established a sinus tract with the intent to drain pus associated with an infection.
  • Maxillary Sinusitis of Endodontic Origin. In some cases, infections in your back teeth can spread into your maxillary sinus. When this happens, you’ll experience sinus issues like runny nose, congestion, stuffiness, facial and jaw pain, and bad breath.
  • Changes in appearance of tooth. If you’ve noticed that the tooth is darkening or changing in appearance, it may be a sign to get it checked out.
  • No symptoms at all. In some cases, you may experience root canal failure with no pain, swelling, or other symptoms. In fact, your first inkling that something is wrong may come from a routine x-ray at your dentist’s office — which is why it’s so important to stay up-to-date with your dental appointments.

If you experience any of these signs, it’s important to see your dentist as soon as possible to prevent further spread of the infection and to work out a plan for treating the failed root canal.

Root Canal Retreatment: Why do I Need Another Endodontic Procedure?

However, as with all medical procedures, there is a slight chance of failure when it comes to root canal therapy. When this happens, it’s important to recognize the signs that something is going wrong — and understand your options for treatment. Seeking a qualified endodontist — a professional who specializes in root canal treatment — is the first step when a root canal goes wrong.

If your root canal treatment has failed, you might need another endodontic procedure. In most cases, seeking root canal retreatment can help save your tooth, decrease your pain, and prevent the infection from spreading. Without adequately addressing the root of the problem, it’s likely that your symptoms will increase — and you may lose the tooth. Here’s what to expect from root canal retreatment:

  1. First, your endodontist applies a local anesthetic and re-open your tooth. They may have to remove the crown that’s in place, and will also remove the canal filling within the tooth.
  2. Then, they’ll meticulously clean the inside of your canals. At this point, they’ll be sure to assess the inside of your tooth very carefully, ensuring that any narrow, curved, or irregularly placed canals are thoroughly cleaned.
  3. Finally, they will fill and seal the canals and place a temporary filling to protect the area. You’ll have to return for a crown as soon as possible to prevent the risk of re-infection.

How much will root canal retreatment cost?

The average cost of root canal retreatment is: $1,186 for anterior teeth, $1,424 for premolars, and $1,581 for molars. Your insurance company might cover some portion of the procedure, and it’s always a good idea to speak to your dental office about payment plans.

For the most part, root canal therapy is a tried-and-true endodontic procedure that alleviates your dental pain, eliminates your infection, and empowers you to keep your original teeth. Compared to the alternative of tooth extraction, root canal therapy is generally a healthier and more cost-effective option in the long run.

Root Canal Surgery: An Alternative to Retreatment 

In certain cases, your endodontist might recommend that you get root canal surgery instead of root canal retreatment. Root canal surgery might be needed in some of the following situations: 

  • To locate small fractures or canals that weren’t caught by x-rays during the initial treatment.
  • To remove calcium deposits in root canals.
  • To treat damaged root surfaces or bone.
  • To remove inflammation and infection around the root.

One of the most common root canal surgeries is called an apicoectomy or root-end resection. Using local anesthetic, your endodontist ensures that you will feel no pain or discomfort during the procedure. With the latest and most innovative technology, your endodontist then uses micro-surgery techniques to open the gum tissue near your affected tooth.

From there, they can easily remove any infected or inflamed tissue. Additionally, they will remove the very end of the root, sealing the area with a small filling and placing sutures or stitches. If the bone has been severely damaged, they may need to utilize bone grafts to promote healing. In general, patients return to their everyday lives just a day after the surgery. Over the course of months, your bone will heal around the end of the root.

What is the cost of root canal surgery?

The cost of the apicoectomy is around $986 – $ 1,302. Keep in mind that there may be extra costs, such as the cost of retrofilling the root. If a bone graft or biopsy is needed, it may cost more. Make sure you talk to your dental office about the specific costs in your situation, since every case is unique.

What are the Alternatives to Endodontic Retreatment and/or Endodontic Surgery?

An untreated failed root canal is a serious infection. It can form a painful and dangerous abscess, and in some cases even lead to a septic infection. When it comes to infected pulp tissue, if you choose not to have endodontic retreatment or surgery, your only option is to have the infected tooth extracted. Though it’s preferable to keep your original tooth if possible, an extraction followed by an implant is sometimes the only appropriate course of action. 

Once the tooth is extracted, your best choice is to have a dental implant placed that will mimic the look and feel of your natural tooth. Depending on the tooth, the cost of a dental implant is between $1,500 and $6,000. Additionally, the extraction itself can cost $50-900per tooth.

Frequently Asked Questions About Root Canal Failure

If you think you may be experiencing root canal failure, you probably have many questions. Although everybody’s situation is completely different — and it’s best to consult your team of dental professionals — here are some brief answers to FAQ’s about root canal failure that may be helpful:

Could My Symptoms Be Traced to Something Else?

Without being examined by a dental professional, it’s hard to know if your signs and symptoms are coming from a different source. For example, some patients develop what is known as Persistent Alveolar Pain Disorder (PDAP), which occurs when you continue experiencing pain after an endodontic procedure — but no infection or inflammation is found. It is unknown what causes PDAP.

In other cases, you may simply be experiencing pain from other sources, such as temporomanidbular joint disorder (TMJ), which involves pain and swelling in your jaw joint. Or perhaps you are experiencing symptoms associated with a nearby tooth, but it’s hard to differentiate the source. Whatever the case, seeing your endodontist will help you get to the bottom of the problem.

What Went Wrong?

If you have root canal failure, you’re probably wondering what went wrong in your treatment. In most cases, failure is linked to one of these conditions or situations:

  • You experienced a new injury or further decay that opened your root up to another infection.
  • The root canal space wasn’t sufficiently cleaned during the first procedure and some bacteria was left behind.
  • The crown over your root canal became cracked or damaged.
  • You have complicated root anatomy that requires more thorough treatment.
  • It took too long to place a crown over your root canal and infection re-established in the pulp.

How Often Do Root Canals Fail?

Out of the whopping 15 million root canals that are given every year — which equals 41,000 performed every day in the United States — an impressive 89% of those patients report being satisfied with the work done by their endodontist. Multiple studies have been done to assess the success rate of the initial root canal. One study published in ISRN Dentistry determined that endodontic treatment is successful in 86% of cases. 

However, success rates can vary based on the type of oral health professional who does the treatment. For example, one 2004 study found that root canal treatment was successful 98.1% of the time when performed by endodontists, but only 89.7% successful when performed by general dentists. Overall, root canal treatment is successful approximately 90% of the time.

What Should You Do About Root Canal Failure?

If your root canal was not successful and you are experiencing re-infection of the same tooth, it’s important to take action with your dental team. There are a few courses of action you can pursue:

  • Retreatment. In retreatment, your endodontist will re-open the affected root canal. Just like in the initial procedure, the filling will be removed and the space will be thoroughly cleaned. To prevent the chance of further issues, your team will use every tool available to ensure that any unusual anatomical variations are recognized and cleaned out. Then, they will seal the space and replace the crown.
  • Surgery. In some cases, your endodontist may recommend a surgery called an apicoectomy. In an apicoectomy, your endodontist uses micro-surgery techniques to access your gum tissue and remove infectious tissue — along with the very tip of the root itself — through the gums.
  • Extraction. Though it is always better to keep your natural tooth, you can also choose in some cases to have the tooth extracted. In this case, you would need to then seek a dental implant, bridge, or dentures to replace your tooth.

How Much Will It Cost to Treat My Failed Root Canal?

It’s true that getting treatment for a failed root canal may cost more than the initial procedure, but this varies considerably based on your situation. For example, cost may vary based on whether you’re treating a front tooth or a molar. And when it comes to having a crown replaced, the material used — porcelain, metal, ceramic, etc — will change the overall cost. Talk to your provider about financing the procedure, or check in with your insurance company to see what they cover.

Experiencing Signs of Root Canal Failure? 

Whether you had a root canal 12 weeks, 12 months, or 12 years ago, it’s important to keep an eyes on your dental health. If you start experiencing signs of root canal failure like pain, swelling, discharge, or a boil on your gumline that just won’t go away — it’s important to seek treatment. Feel like you may be experiencing a failed root canal? Get in touch with your local team of endodontists today.

Talk to your Specialist About Your Options

If you’re suffering symptoms of pain, swelling, or discharge in a root-canal-treated tooth, it’s important to seek treatment right away. Talk to your endodontist about which treatment options work for you.

At Omega Dental Specialists, we take pride in providing quality dental and endodontic care to our patients in the Houston area. From root canal retreatment to root canal surgery to extraction and implants, we explore all options — and choose what works best for you. Please contact us today if you have any questions, or to schedule a consultation.