What is a root canal re-treatment?
A tooth that has been root canal treated can last many years, particularly if it is appropriately restored following root canal treatment (e.g. with a crown). On occasion, teeth that have had a root canal treatment can fail to heal or become infected again. This can happen months or years after the original treatment. If a root canal treatment has failed it may be noticeable: The tooth becomes painful and/or a sinus (gum boil) appears. Sometimes, there are no symptoms from
the tooth and the failure of the treatment is detected on an x-ray as a dark shadow associated with a treated tooth. Carrying out a root canal re-treatment can give a tooth a second chance.
Why does my root canal treatment need to be re-done?
The previous treatment has not allowed healing as expected and the infection will not heal without further treatment. Failure of a root canal treatment can happen for many reasons including:
Most commonly:
- Bacteria (infection) remaining within the root canal system e.g. a missed or incompletely filled canal
- New bacteria have entered the root canal system e.g. through a lost or leaking filling/crown/bridge; decay; root cracks/fractures.
Less commonly:
- Infection has spread from within the root canal and into the surrounding tissues.
- A reaction to filling materials placed beyond the root canal into the tissues surrounding the root.
- A cyst has developed at the end of the root
How is root canal re-treatment done?
This involves a local anaesthesia
If there is a filling in the tooth, a small access cavity is made through this.
If there is a bridge, crown and/or post in the tooth, this will need to be removed to gain access to the root canal filling.
If this can be done keeping the bridge, crown and/or post intact, it might be possible to use them again following
treatment. If not, they will need to be re-made.
The previous root filling is removed to allow any infected parts of the root canal system to be accessed and cleaned.
Any other ‘complications’ (such as missed canals, blocked canals, broken instruments) can be tackled at the same time.
To ensure that the entire previous root filling is removed and missed canals found, it is essential to use a microscope.
This magnifies and illuminates the root canal system.
Once the root canal system is as clean as possible, the root canals are refilled and covered to protect them from further bacterial infection. As soon as the root canal re-treatment is complete, a permanent restoration should be placed.
In few complicated cases the teeth may have to be removed.