Root canal treatment complications, problems and reasons for failure and retreatment.

No doubt it is the hope of your dentist that the root canal treatment they provide for you will allow your tooth to last a lifetime. This can certainly be the case and hopefully the outcome you will experience.

What can cause root canal treatment to fail?

Previously we described some of the goals of root canal treatment:

It removes bacteria, toxins, unhealthy nerve tissue, and irritants that are present in a tooth. It fills in and seals off the nerve space inside a tooth so physically there is no location where bacteria and tissue irritants can exist and be out of effective reach of your body's defense mechanisms.

If after root canal treatment has been performed a tooth still harbors bacteria or irritants which keep the tissues surrounding the root of the tooth from being healthy (inflamed), then the treatment has not been successful. Some signs of failed root canal treatment can include tooth pain (ranging from very mild to extreme) and tenderness or swelling in the gums in the area near the tooth (ranging from very slight to pronounced). These signs can either:

Persist from the time of the root canal treatment. Be transient (varying week to week or month to month). Appear even though the tooth has been asymptomatic for years.

In other cases a tooth may have been, and continues to be, without symptoms but the tissues surrounding the tooth are identified as having the presence of persistent inflammation by way of a x-ray examination by a dentist.

In general, the presence of problems indicates that, despite your dentist's best efforts to clean and seal up the tooth, bacteria or tissue irritants have found some location in which to persist beyond the reach of your body's defense mechanisms. As a result there is persistent inflammation in the tissues that surround the tooth's root. Here are some of the reasons why this scenario might occur:

The shape of any tooth's root canals can vary greatly. As an example, there can be root canals that have branches or forks in them. This branching can be hard for a dentist to detect and, as a result, one branch may be cleansed and sealed while the other branch is left untreated. A tooth may have more root canals than is normally anticipated. In these cases, especially when the unexpected root canals are very tiny, your dentist may not discover them and as a result not clean and seal them. There is a crack in the root of the tooth. These cracks can be very small or else in a location in which your dentist cannot detect them. The tooth has a defective or inadequate dental restoration and as a result bacteria have been able to seep past this restoration on into the inner aspects of the tooth and recontaminate that area originally cleansed and sealed off by the root canal treatment. This phenomenon is termed "coronal leakage." [ More about coronal leakage and how it can be the cause of root canal treatment failure. >> ] Even though a tooth has been expertly cleaned and sealed, with the passage of time the integrity of this seal can degrade, thus allowing bacteria to recontaminate the interior aspects of the tooth.

Your dentist will have to evaluate your specific situation and advise you as to if they think the retreatment of your tooth is likely to resolve your problems. They may offer to perform this treatment themselves or they may feel that the expertise of an endodontist is warranted for your case. If retreatment is not a possibility then the tooth should be extracted.

Other problems and complications that can occur with teeth that have had root canal treatment.

The tooth has broken in a fashion that cannot be repaired.

Teeth that have had root canal treatment are seldom as structurally strong as they once were. These teeth often require a dental crown so to adequately strengthen and protect them.
[ More about how dental crowns can protect endodontically treated teeth. >> ]

The tooth has extensive decay or gum disease.

Teeth that have had root canal treatment are not impervious to tooth decay and gum disease, both of which can lead to the loss of the tooth. You must brush and floss your teeth effectively so to prevent the occurrence of these problems.