The TFRK™-MT is a flat-ended modified #3 Gates Glidden Micro-Trephine bur. It has a tiny cylinder with cutting blades on its tip to create a trough or stage around the coronal portion of the separated file. The inner diameter of the trephine is 0.45 mm so that it can cut around separated files with diameters smaller than 0.45 mm at the broken edge.
