Often, I have patients that are reluctant to have a root canal. Either they have had a bad experience or later lost a tooth that had a root canal, or a friend or family member has. With a 90% success rate, this does not happen often, but it can. The reasons are not numerous and the most common one can be controlled.

Most teeth that have had a root canal and fail have extensive decay into the root surface. This has happened because the patient failed to have a filling, or crown placed on the tooth. They left the office and felt better, and never returned to complete the treatment. The access hole in the tooth, which is drilled to allow entrance into the nerve chamber, has to be sealed with some sort of permanent filling. When the root canal is completed, a temporary filling is placed which after a few weeks crumbles and allows food and bacteria into the tooth. Decay starts, which naturally does not hurt since the tooth had a root canal. But,  in a short time there are problems.

The most common problem is that the tooth breaks since it has been weakened by the root canal and the decay. This could have been prevented with a filling or crown. The other reasons for failure are more nefarious.

The root of the tooth can be fractured. This can happen before the root canal or after the treatment has been completed. A fractured root is difficult to diagnosis since the fracture is microscopic. It is only discovered after the fact when the patient is still having problems with the tooth despite having a root canal. In most cases, the only option is to remove the tooth. Root fractures are not very common, and are a small percentage of the reasons for failure.

The next reason is a recurring infection. This can be caused by the dentist not completely cleaning out the root and some tissue is left in the tooth which creates an infection and pain. The other part of this recurring infection situation can be a nerve that was not treated when the root canal was finished. The nerves can be very small, and some times difficult to locate. The good news is that in most cases the tooth can be retreated with a new root canal.

The other procedure for re treatment of  the root canal is apical surgery. This means that the root of the tooth is exposed surgically and a small portion is removed. The area is cleaned out and a small filling placed in the tip of the root. The area is then sutured closed. In most cases this would not be the first choice for treatment of the problem with a failed root canal since it is drastic. However, it is effective and can solve the situation.

This is just a short over view of the root canal and what can be done to save a tooth which has died or had some trauma which has caused the nerve to die. If you need a root canal it is important to follow through on the treatment. Don’t stop after the root canal! Have the core and crown completed in order to ensure that the tooth does not break or begin to decay again.