Gates-Glidden drills and Peeso reamers are high-end instruments used for accessing the root canal and enlarging the opening of the coronal part, before and after using endodontic files and reamers. They are also used for dental filling removal and pin or post hole preparation.

The main difference between Peeso reamers and Gates-Glidden drills is the shaping ): the Gates-Glidden drill head is much shorter and the shaft is thinner.
The end of these drills and reamers consist in a fine blunt nipple and therefore non-cutting, preventing perforation of the canal and the damaging of the walls during drilling. The normalized shank of these devices allows them to be easily mounted on rotary instruments.