Nickel-titanium rotary-file canal preparation and intracanal file separation.

Nickel-titanium (Ni-Ti) rotary files have become a mainstay in clinical endodontics because of their ability to produce smooth tapered canal preparations with reproducible results. In contrast, intracanal file separation has become a nightmare for many practicing dentists. Factors attributed to breakage of rotary files include canal curvature and other anatomic challenges, practitioner experience, frequency of use, and speed of rotation. When the practitioner is familiar with the instrument and is experienced with its use, Ni-Ti files can be an important adjunct to the practicing dentist and should not cause anxiety.