Tooth Abscess After Root Canal

Tooth Abscess

As a part of the root canal treatment procedure, the entire pulp of the tooth is removed and the crown and root are cleaned. It is undoubtedly one of the most painful procedures that any individual has to go through. However, it becomes a necessity when the tooth infection crosses the enamel and dentin and reaches the pulp.

In most cases, root canal treatment ensures that the person doesn’t suffer from any sort of infection in the future. At times, however, a person may end up with a tooth abscess after undergoing root canal treatment, and that can cause further complications when left unattended.

Causes of Dental Abscess After Root Canal

Basically, tooth abscess is pus formation, which can be attributed to bacterial infection that has accumulated in the soft pulp of the tooth. In the case of a root canal, it can occur when the procedure is not carried out properly, or when a faulty crown is used. Discussed below are the most prominent causes of tooth abscess after the root canal procedure that you need to be aware of.

Improperly Done Root Canal

It is one of the most common causes of a tooth abscess. It can be attributed to several different factors that come into play when one opts for a root canal. At times, for instance, the canals are not treated properly as they are very curved or narrow. At times, the filling inside the root canal does not extend up to the tip. As opposed to this, sometimes the filling in the canal even extends into the bone. Also, there are cases wherein there is an extra canal present in the root, which the dentist fails to anticipate even after opting for an X-ray.

In all these cases where a root canal is not properly filled or even one canal of the tooth is not filled, it becomes an open ground for the proliferation of bacteria, which, in turn, leads to the formation of dental abscess.

Cracked or Perforated Root

At times, as a last-ditch effort to save the tooth, the dentist may go ahead with a root canal, despite knowing that the chances of success are only 50 percent. This is especially the case with front teeth, where there are chances of fracture or cracks in the root due to trauma to the teeth. These cracks can become pathways for bacteria to pass into the tooth even after proper root canal procedure, eventually leading to tooth abscess.

Similarly, in some cases, the dentist may unintentionally perforate the tooth during the root canal of a posterior tooth, which, in turn, can make the tooth vulnerable to an abscess.


Reinfection can occur even when the treatment procedure is properly carried out, due to several reasons. As the tooth is still present in the vicinity of the bone, an infection can spread from the neighboring tooth, resulting in the root canal-treated tooth getting infected. When an infection spreads from neighboring teeth, it usually shows in the form of swelling in the oral cavity and an abscess on the gums.

Another cause for reinfection is if the infected tooth was lying in the oral cavity for a long time, due to which there was a large infection present in the bone before root canal therapy was initiated. No matter how well the root canal is done, if antibiotics are not taken and precautionary measures are not followed, then the risk of such infection leading to a dental abscess cannot be ruled out.

No Crown or Faulty Crown

In most cases, the dentist will recommend a dental crown after the person has undergone root canal treatment, to protect the tooth from the onslaught of germs and bacteria that are present in the oral cavity and saliva as well as the ones which come from the food we eat. If the person doesn’t get a crown fitted, then there are chances that the tooth will get infected once again and a root canal will fail.

The problem may also arise if the person gets a faulty crown fitted, or if after many years the crown gets a few cracks and wears out. In both these cases, there are chances that bacteria will seep in and cause an infection in the root canal-treated tooth.

Dental Abscess Treatment

The treatment mostly depends on the underlying cause. The dentist normally drains the pus by lancing the abscess or drilling a small hole in the tooth. If the pus is not drained completely, he will prescribe antibiotics to curb the infection and provide relief from symptoms. The person will have to undergo the root canal procedure again to get rid of the dead pulp tissue to eliminate the chances of infection in the future. If the infection is too deep and the dentist feels the tooth is not salvageable, then the only option left is to extract the tooth.

If the person feels pain or finds that there is a swelling associated with your root canal-treated tooth, then he should promptly consult a dentist.


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