What is the most common cause of failure in root canal treatment?

The most common cause of failure in root canal treatment is that the canal is not filled completely. Successful root canal therapy relies on the thorough cleaning, shaping, and sealing of the root canal system. If the canal is not filled completely, it can leave spaces for bacteria to thrive, leading to reinfection. Incomplete filling may occur due to various factors, such as the complexity of the root canal anatomy or the presence of previous untreated infection, which can obstruct proper filling.

A complete fill of the canal system ensures that all potential pathways for infection are adequately sealed, preventing future complications. It is crucial for the dentist to accurately assess the anatomy of the tooth and ensure that all parts of the canal are effectively treated to avoid treatment failure.