What substance is commonly used for root canal filling?

Gutta-percha is the substance most commonly used for root canal filling due to its favorable properties. This material is a thermoplastic elastomer, which means it can be softened when heated and then molded to fit the root canal space effectively. It provides an excellent seal to prevent reinfection of the tooth and is biocompatible, making it safe to use within the human body.

In a root canal procedure, after the tooth is cleaned and shaped, gutta-percha is placed into the canal to fill the space and maintain the integrity of the tooth structure. Its ability to create a hermetic seal is crucial for the long-term success of the treatment, minimizing the potential for bacteria to re-enter the tooth.

While other materials like amalgam and composite resin are used for restorative purposes in other areas of dentistry, they do not have the same properties suited for the specific requirements of root canal therapy. Additionally, limestone cement is not typically employed in this context, as it does not provide the same sealing ability or flexibility required for canal filling.