I like both reciprocation and rotary I CANNOT BELIEVE IT when colleagues say they only use rotary - reciprocating files will save TIME AND STOCK to neglect a concept that gives you this power is like neglecting advancements in technology! I also use rotary for the extremely curved canals that I treat because I like the fact I can control the RPM and torque settings rather than have them preset like reciprocation AND if I need the security of a shaper and glide path because using wider finishing

This is the difference between piston and rotary engines! | Car Throttle

Let's take a closer look at Rotary engines | Engineering Explained