A barbed broach is a hand-operated endodontic tool used to remove the pulp tissue during root canal treatments.
They have been in widespread use at least since the early 1900s, and their introduction allowed dentists to remove tissue from much smaller root canals than before.
These barbs are designed to entangle the tissue so it can be removed intact from the canal wall.
[1] Often thinner than barbed broaches and sometimes made of carbon steel, they are less prone to collapsing in fine canals.
When Maynard demonstrated their use in St. Petersburg in 1845, using a watch spring filed down to a hair's thickness, Czar Nicholas was so impressed that he offered to appoint Maynard as Actual Dentist to His Imperial Majesty.