Combining Linear Oscillation and Rotation

Whether the combination of linear oscillation and rotation is effective and safe depends to a great extent on several factors.

How far does it rotate?

What is the helical angle of the file?

Is the file a positive rake likely to screw itself in during the clockwise rotation?

Is the linear movement sufficient to affect cutting?

It is a mistake to assume that it is the handpiece that is doing the cutting.

It is the file that does the cutting.

So before determining whether a given combination of linear oscillation and rotation is effective, safe, functional, efficient, all these factors must be taken into consideration.

After you have studied the concepts of circumferential filing, interflute distance, helical angles, push-pull probing, included tip angles etc, then you will be able to make a judgment based on all these factors for the given handpiece and file combination.