Root canal treatment: Complications, Problems, Failures.
While the root canal therapy you've had performed for your tooth will hopefully last you a lifetime, complications, and even outright treatment failures, can and do occur.
We've divided this topic up into the following subjects:
A) How can you tell if your root canalled tooth has a problem?
The signs of failing root canal therapy are often the same as those symptoms (discomfort, swelling) that signaled the tooth's initial need for treatment.
We discuss these signs here: How can you tell if you need root canal treatment?
If your tooth isn't symptom free, it should be evaluated.
For the most part, if you have a tooth that's had root canal treatment and it still has or has started to show pretty much any type of symptom, it should be evaluated by your dentist.
Side note: There can also be cases where a tooth has been (and even continues to be) symptom free but a dentist's x-ray examination reveals a problem.
B) Why does root canal treatment fail?
Root canal failure indicates that either:
- The cleaning aspect of the tooth's procedure was incomplete or ineffectual.
- The seal that was created during treatment has not been successful in keeping contaminates from seeping in or out of the tooth. Either it was deficient initially, or else has since deteriorated.
Specific reasons why root canal treatment may fail.
Here are some examples of how the above problems may come about.
- Canal branches - Root canals sometimes fork, and these divisions, which may be very minute, can be hard to detect and access. Because of this, one canal branch may be properly treated while the other is totally overlooked.
- Hidden canals - A tooth may have more root canals than is expected. And in these cases, and especially when the unexpected canals are very tiny, the dentist may not discover them. If not, they will remain untreated and a cause of problems.
- Root cracks - Cracks that have formed in the roots of teeth can't be treated, in the sense that they can be cleaned and sealed like root canals.
When performing treatment, a dentist may be unaware that a crack is present (in some cases they can be impossible to identify), or underestimate the significance of the ones they see. In other cases, the root crack that has caused the problem formed after the tooth received its treatment (see below).
- Deterioration of the seal - Even though a tooth has been expertly treated, over time the integrity of the tooth's seal can degrade, thus allowing contaminates to reenter its nerve space.
- An inadequate dental restoration - A defective or inadequate final restoration (placed after the competion of treatment) can allow contaminates to reenter a tooth. (The x-ray graphic above shows an example of this.)
This phenomenon is termed "coronal leakage" and it is a major cause of root canal failure. For a more detailed discussion, use the button to the right.
- Lack of clinician expertise. - Research has shown that treatment provided by endodontists (root canal specialists) has a higher success rate than that provided by general dentists.
C) Contributing / Complicating factors.
It's possible that your tooth's treatment has been successful but the tooth itself has problems due to other factors and issues.
a) The tooth has broken or fractured.
Teeth that have had root canal treatment are seldom as structurally strong as they once were. And for this reasons, they often require the placement of a dental crown for strength and protection.
If an endodontically treated tooth does break, it's not always a big problem.
- Assuming that the damage is confined to just the crown portion of the tooth (not the root), it's quite likely that the tooth can be repaired. (In some instances, the tooth may require a dental post and core.)
- If the crack extends into the tooth's root, a serviceable repair may or may not be possible.
b) 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.
D) What's the fix for failed root canal treatment?
Root canal cases that have failed can be retreated, usually employing the same procedure that was used originally. We now discuss this topic here: Root canal retreatment. Your dentist may offer to perform this work, or they may feel that the expertise of an endodontist is needed.
As mentioned above, treatment failures involving root cracks may be impossible to treat. If so, the tooth should be extracted and replaced.