I know that all the manufacturers are encouraging you to shape the canal oriface with their special oriface shaping files, but I still like to use the gates glidden drills to open the upper third of the root canal system.
Quick research this morning indicates a gates glidden drill costs me $3.12 and a NiTi rotary instrument costs me $7.15 (taking into account the endodontist's bulk discount).
Call me "old fashioned" but why anyone would want to pay twice as much for an instrument that takes twice as long to do the same job is beyond me. The gates is non-end cutting and also improves the direct line access into the canal, which will help prevent separation of your rotary files. The shaft of the gates is somewhat flexible and usually, if there is a separation, it will separate high on the shaft and is easily removed with a pair of cotton pliers.
If I had to guess, I would guess that nineteen out of twenty times a gates glidden drill breaks, it breaks high on the shaft. That being said, here is a case where the gates separated in the mid-shank area. When this occurs, it just the same as if a rotary file separates. It can be just as difficult and time consuming.
Technique for removal is the same as with a rotary instrument. Visualize it, ultrasonic instrumentation around the instrument until it loosens, and retrieve.