Root canal treatment is a procedure that is meant to “save” an infected tooth from being extracted.

When it is carried out under proper protocol, it can be a very successful procedure. Scientific literature has shown that the success rate of root canal treatment is approximately 90%.

In a small percentage of teeth, sensitivity after treatment may persist for a longer period of time before settling down. This could be due to some canals having branches that cannot be completely cleaned in a conventional way.

Causes of root canal failure

Complicated root canal anatomy rendered
Root canal anatomy rendered

Re-infection of the root canal system of teeth is one of the causes of root canal failure. In certain teeth, the root canal anatomy can be very complicated and the outcome may be unpredictable. If there are root canals that are not properly negotiated and cleaned, or have branches that cannot be properly accessed, an infection may recur in the future. Molar teeth (back teeth) generally have 2 or 3 roots, with each root typically having 1-2 canals. Typically, a molar tooth has 3-4 canals. However, in some rare cases, a tooth can have up to 6 canals!

Hairline vertical root fracture
Vertical root fracture

Besides re-infection of the root canal system, vertical root fracture is another cause of root canal failure. Vertical root fractures are often only discovered at a late stage, that is, when the surrounding gum tissues has become tender and/or irreversibly infected. In the majority of cases, an extraction of the tooth will be necessary. However, in selected cases, the fractured part of the tooth can be removed surgically, leaving the rest of the tooth in place.

Factors affecting prognosis of root canal treated-teeth

The prognosis of the root canal-treated teeth is also affected by the health of the surrounding gum tissues. If the tooth has gum disease, the prognosis of treatment will be decreased.

The presence of cracks is also another factor. Many teeth nowadays present with cracks. If the crack line has extended below the gum level, the long-term prognosis of treatment is poor. Teeth that carry a long span bridge are more prone to developing cracks after a root canal treatment.

You should discuss with your dentists

  • the diagnosis and nature of the proposed treatment
  • the risks reasonably associated with the proposed treatment or procedure and the prognosis
  • feasible alternatives to the proposed treatment or procedure and the risks associated with declining treatment.