Which instrument is used for initial shaping of the canal by twisting motion?

• A. Rotary paste-filler
• B. Resin bond
• C. Root canal file
• D. Root canal reamer

Answer: (C)

The key idea is that early canal shaping is done with hand files using a twisting, watch-winding motion. A root canal file is specifically designed for negotiating the canal and removing dentin in a controlled way with this twisting technique. This creates a smooth, patent pathway and establishes a glide path for subsequent canal preparation.

Rotary paste-fillers are used for filling gutta-percha later in the procedure, not for shaping. Resin bond is a bonding agent, not an instrument. A root canal reamer can enlarge a canal, but the twisting, manual shaping action described here is most characteristic of using a root canal file, which provides tactile feedback and precise control during the initial shaping stage.