What is the primary action of a reamer file in root canal treatment?

The primary action of a reamer file in root canal treatment is to remove dentin structure. Reamer files are specifically designed to prepare the root canal by enlarging and shaping it, which is crucial for effective cleaning and disinfection. During root canal therapy, the goal is to create a space within the canal that can be easily accessed for removal of the infected pulp and debris. By removing dentin, the reamer file helps achieve the necessary canal shape and size, enabling better access for irrigation solutions that disinfect the canal, as well as facilitating the placement of root canal fillings.

While other actions like packing the canal, disinfecting, or protecting the pulp are essential components of the treatment process, the specific function of the reamer file is focused on altering the canal's geometry by removing tooth structure, establishing the groundwork for successful endodontic treatment.