Failed Root Canal: The Causes, Symptoms, Complications and Treatments

Many factors can cause failed root canal. When you do root canal treatment, it is important to place the permanent restoration or crowns on the treated tooth as soon as possible. Not only that, but you also should maintain the restoration routinely by having impeccable hygiene and dental check-up. Doing root canal treatment is good to save your tooth so it can last a lifetime.

In fact, it is not as easy as that. Maintaining the treated tooth is about your commitment because you are dealing with the root canal system, which is complex.

failed root canal

What Are The Causes Of Failed Root Canal

  1. Re-infected root canal

The failure may happen because the root canal is re-infected because of the leaked restoration.

One of the common reasons why failed root canal may happen is because of the extra canal in the tooth beyond the expectation. In fact, lower incisors commonly have one canal, but these teeth may have a second hidden canal behind the first. Besides, molars with three roots may have four canals. Therefore, if the dentist cannot find the extra canal, it can become infected and it brings to a tooth abscess.

For the front teeth, they have single roots as well as canals. Therefore, they are easier to treat. On the other hands, back teeth have more roots as well as canals. In addition, the research found that there is a significant correlation between the risk of a tooth to fracture and the aging. Your teeth can be weaker at the time and therefore, there is a higher tendency to get cracks or fracture. Other than, the delayed crown placement and other restoration after the root canal treatment can cause bacterial re-infection.

  1. Does not support the root canal treatment with good oral hygiene

In addition, root canal failure occurs because you failed to support it with good oral hygiene.

  1. Broken Sealing Materials

In some cases, it can happen because of broken sealing materials at the time.

Furthermore, gum disease or caries can develop on the roots of the treated tooth. This case is the same as another natural tooth. It is good to brush and floss your teeth routinely and thoroughly. You should also visit your dental hygienists to make sure that you get regular scaling so that the gums are still in a good condition.

  1. Untreated Branch

In some cases, an obstruction can prevent your dentist to clean the entire canal of the tooth. For example, curved and narrow root canals can create complications. It is possible to have extra canal branches, which is difficult to reach by the instruments of your dentist because it is too deep.

When there is failed root canal, you may not get any signs, especially when the tooth gets a cavity. It is because your dentist used root canal cement as well as Gutta Percha to seal the canals. In addition, root canal treatment means that your dentist removed the inner part of the tooth, which is the nerve. You may feel pain because the tooth is fractured such as grinding or something that makes it trauma or the presence of an abscess.

What Is The Failure Rate Of Root Canals

A failed root canal can happen from 5% to 15% of the cases. Therefore, the root canal or endodontic treatment depends on your commitment to keeping your mouth healthy. Still, it is possible if there is something wrong with the treatment that is still hard to know the cause after you have already done the treatment.

For the successful rate, it is good to handle failed root canal as soon as possible. The re-treatment or surgery success rate is from 50% to 75%, depends on the cause.

failed root canal

Root Canal Problems And Failures

Besides, the vertical root fractures can crack from the root of the tooth and then it will spread to the chewing surface. However, rarely it can be a mishap, especially during the root canal treatment. For example, if the files lodged in the canal and if the dentist has problems to get the filling instrument around the curves. Commonly, it is still possible to retrieve the files, but many times, these are impossible to do so. During the instrumentation process, ledges are possible to develop so that it is difficult to complete this treatment.

What Are The Symptoms Of Failed Root Canal

There are many failed root canal signs and symptoms. The symptoms are the same as the original tooth that requires treatment as below:

  1. Tenderness, sensitivity, and pain
  2. Some amount of swelling is possible. Other than that, the tooth or the persistent gum near it may have an odor coming from the area. It is possible to have bad taste.
  3. The symptoms above can be constant or intermittent. It is also possible to disappear completely by the time. The level of activity from the infection can reduce the intensity of the symptoms and even disappear.

When the tooth develops a crack, it is impossible to seal the canal. Therefore, the infection can happen to re-enter the tooth. The vertical root fractures can show the minimal symptoms. After that, there is no sign you can feel. It sounds like a sudden attack when you found that the bone and the gum are infected.

Not All Symptoms Indicates Failed Root Canal

However, it does not mean that experiencing the symptoms indicate failed root canal. There are some possibilities that the symptoms are not because of the failure. Here are some possibilities:

  1. The pain

It is possible if the medical problem makes the nerve to create a sensation that seems the problems are from the root-canalled tooth.

  1. Phantom pain

This is one of the tooth sensations that is a little bit similar to phantom limb pain amputees that you may experience.

According to Marbach in 1993, the pain stems from the type of traumatic parts that has happened, connect to the nerve that works for the tooth. For example, the dentist removed the tissue from the treated tooth during the root canal treatment. This condition is possible to happen in 3% of the cases.

failed root canal

The Complications of Failed Root Canal

For many of us, we have not had any problems after we had root canal treatment. However, still, there is a risk of failed root canal complications after the surgery. Therefore, it is important to understand it before you have surgery so you can prepare everything well, including the recovery period.

In fact, the treatment has a 95% of success rate with no complications. However, those with medical or dental procedures may experience some complications as below:

  1. Broken Canals

During the process, your dentist will use a small dental file to clean the infected area from the canal walls. Even though some canal walls are wavy and the dental instruments are durable, still, this process can break the parts. There will be no complications if your dentist can perform the retrieval of the broken piece successfully.

  1. Sinus Congestion

It is because the roots of some teeth are close to the sinus cavity. Therefore, doing a root canal treatment may create inflammation around the sinus cavities that will lead to congestion. Fortunately, this complication will disappear several weeks after the treatment.

  1. Re-infection

Your dentist added two seals in a root canal. We call it Gutta Percha as the inner seal. Another is the crown for the outer part of the treated tooth. These seals are durable to deal with tremendous abuse. However, they cannot handle erosion. Once a single or two seals fail, bacteria can grow there and lead to an infection again. The key is to perform proper care.

  1. Crown Fracture

During the root canals, your tooth dies because of the pulp removed by your dentist. Therefore, they can save the tooth from infection. On the contrary, it can cause the tooth brittles. For this reason, you should add crowns to strengthen the outer part of the tooth.

  1. Tooth Discoloration

Why does it happen? It is because the dead roots of the treated tooth permeate to the dentin. This is a rare case and it is still possible to treat.

  1. Paraesthesia

This complication caused by failed root canal is quite rare. It can cause numbness because the treatment disrupts the nerves surrounding the area. it can go away for few weeks.

  1. Anesthesia

A failed root canal may also lead to anesthesia reaction because of the extreme allergic reaction. If you experienced this on your previous medical treatment, make sure that you tell your dentist as soon as possible before the next treatment.

failed root canal

What Are The Treatments Of Failed Root Canal

When failed root canal occurs, your dentist may recommend you to do tooth extraction. It is possible to do endodontic surgery if the dentist can save the tooth by removing the fractured root.

In addition, your dentist can do re-treatment to solve the problems. Here, your dentist will treat into the tooth, remove the broken or old endodontic filling material, re-fill the tooth with the material and performs better seal. Other than that, your dentist may send you to an endodontic specialist with the special tools and methods to handle the failed treatment.

Other cases, having root canal surgery can be the solution to answer the problem. One of the surgery types for a failed root canal is apicoectomy. It means that the dentist will access the root of the tooth. The dentist will create the incision in the gums and bone. For this treatment, the dentist will remove the tip of the root, clean the area and seal it from the end of the root.

In some conditions, pain after having root canal treatment is hard to diagnose. This condition can bring some problems beyond the root canal area. For example, you may get gum problems, TMJ, heart attack, sinusitis, as well as pain around the adjacent tooth.

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