A patient attends for a root canal stage 1 treatment. Which instrument would be used to remove infected tissues?

In the context of root canal treatment, the primary goal during the initial stage is to remove infected pulp tissue from within the root canal system. The barbed broach is specifically designed for this purpose. It is an endodontic instrument that features barbs along its length, allowing it to grasp and effectively remove soft, necrotic tissue from the canal.

The barbed broach is particularly advantageous because its design facilitates the extraction of tissue while minimizing damage to the canal walls. This is crucial for maintaining the integrity of the canal structure as much as possible during treatment.

Other instruments listed have different primary functions. For example, a Mitchell's trimmer is usually employed for finishing and contouring dental restorations rather than for pulp tissue removal. The rotary paste filler is used in the filling stage of root canal treatment, applying filling materials rather than removing infected tissue. A periosteal elevator is designed to lift the periosteum from the underlying bone and assist in surgical procedures, making it unsuitable for the task of removing infected pulpal tissue.

Thus, the barbed broach is the most appropriate and effective instrument for the removal of infected tissues in the root canal during the initial treatment stage.