Improper healing may be caused by:
- Curved or narrow canals that were not treated during the initial treatment.
- Complicated canals that went undetected during the initial treatment.
- The crown or restoration was not placed within the appropriate amount of time following the procedure.
- The crown or restoration that did not prevent saliva from contaminating the inside of the tooth.
In some cases, new problems can influence a tooth that was successfully treated:
- New decay can expose a root canal filling material, causing infection.
- A cracked or loose filling or crown can expose the tooth to new infection.