<prompt> A giromatic handpiece for endodontic instrumentation operates by a:Rotating motionOscillating motionZig-Zag motionAll of the above  <response>: Classification of endodontic instruments according to method of use:Group I: Hand-operated endodontic instruments Example: Broaches, files, reamers. Group II: Nonrotary endodontic instruments Engine driven instruments: Reciprocating or quarter-turn motion. Vertical stroke along with quarter-turn motion.Ultrasonic and sonic instruments Group III: Rotary endodontic instruments used with a handpieceSlow speed rotary stainless steel instruments.NiTi rotary instruments.Key concepts Commonly used reciprocating handpiece is Giromatic handpiece. It rotates with quarter-turn motion at 3000 rpm.Since this motion quarter turn to and fro oscillation resembles motion of steering of a ship, it is called Giromatic. 