What instrument is used to remove pulpal fibers from a necrotic tooth?

The broach is specifically designed for the removal of pulpal tissues, including necrotic fibers, from the canal of a tooth. Its unique structure, often resembling a thin, pointed metal wire with barbs, allows it to effectively grasp and pull out soft tissue within the root canal system. This property makes the broach particularly suitable for procedures in endodontics where the cleaning and shaping of the canal are necessary.

In comparison, other instruments like an excavator are primarily used to remove carious dentin and debris; they are not designed for the delicate task of extracting pulp tissue. A scalpel is utilized for making incisions in soft tissues but does not serve to remove pulpal fibers. Forceps are used for tooth extraction and are not applicable in the context of canal treatment or pulp removal. Therefore, the broach stands out as the correct choice for effectively removing pulpal fibers from a necrotic tooth.