During broken file removing procedure it is extremely important to block canal orifices. After You locate broken file in canal, close other canals orifices. Once I forgot about it and that gives me additional work. File jump out from one canal directly to another one. I used to do it with cotton pellet but teflon tape is much more comfortable. It is easy to remove after procedure. You can buy it in plumbers shop, divide to small portions and autoclave it. It is brilliant!