In a few cases, the original root canal procedure may need to be retreated due to persistent bacteria within the tooth. Here are a few potential causes for persistent bacteria inside the tooth:
- The permanent restoration was not placed in a timely fashion, which re-contaminated the tooth due to leakage from saliva.
- The natural tooth structure became decayed and bacteria entered the root canal system.
- A previous existing infection with the tooth did not properly heal with root canal treatment.
- Previously treated canal space was not sufficiently cleaned.