The anxiety caused by file separation during endodontic treatment can be almost overwhelming. The file’s just separated, you’ve heard that distinctive pop. Now what? While there are numerous solutions that have taken on the great task of removing a separated file as simply as possible, it can be said that the best solution to file separation is to explore the possibility of using an oscillating motion – the classic wrist-watch movement – to instrument and shape canal spaces.
One such system is the Endo-Eze Anatomic Endodontic Technology (AET) system from Ultradent. The AET system uses more traditional, high-grade stainless steel files in an oscillating handpiece. The flutes on the AET shaping file rise to the hub of the file, giving the file maximum lateral working length as the oscillating motion causes the file to move itself along the chamber walls while removing necrotic tissue and dentin. Additionally, the more anatomically based a cleaning and shaping system can be, the more sensitive and respectful it is to a canal’s natural shape. It has been shown that rotary systems, while effective in principle related to their desired end result, can remove more healthy tooth structure than is necessary by creating a conical, round space in a canal that may be tubular and laminar.
The issue of file separation is not a problem with AET because of the natural oscillating shape of the handpiece and the stiffer, durable materials contained in the stainless shaping and apical files.
One way to ensure that separation is not an issue with the AET system is using the ambitious, stouter upper third of the shaping file to “brush and mill” the walls of the canal on the upstroke. It can be a tendency to treat the AET handpiece and file like a rotary system by using an up/down, in/out motion. Instead, the AET handpiece needs to apply pressure on the outstroke, relax on the instroke, all the while brushing and sweeping the walls of the canal. This ensures the maximum utility of the cutting surfaces on the thickest parts of the file. Because the cutting is so efficient, the procedure can actually take less time than with a rotary system.
Another trick to ensure the maximum utility of the three AET shaping files during the bulk cleaning and shaping portion of the procedure is to maintain patency throughout the procedure by hand instrumentation and copious irrigation of the canal between the uses of each mechanical shaping file. After establishing patency with a #8 or #10 apical file to length, flood the canal space with sodium hypochlorite, followed by a chelator or conditioner like File-Eze EDTA. Use a sequentially larger K-file to establish patency, then move to the next shaping file.
A final tip to avoid file separation is to establish an open, accommodating straight-line access. Keep the files as straight and linear as possible, particularly in the portions of the file that remain in the pulp chamber during instrumentation. This will ensure their maximum effectiveness. These techniques, as well as others that have been developed over time, will help you avoid file separation during a root canal procedure, especially with an oscillating, anatomic system like the AET system. File separation is rarely, if ever a concern, even when using an active milling action during the cleaning and shaping process.