The main purpose of endodontic treatment is to remove and prevent infection of the root canal system through good endodontic preparation and three-dimensional obturation of the canals. The root canal instrumentation needs to preserve the existing root anatomy, the position of the apical foramen and the original curvature. One of the greatest advances of the 1980s in the field of root canal preparation was the development of the NiTi alloy for endodontic instruments. Rotary NiTi instruments were introduced to improve root canal preparation because they deliver simpler and faster shaping. In recent years, new manufacturing processes and alloys have been developed by improving conventional NiTi, such as CM-Wire and Gold-Wire. Another improvement has been the reciprocating motion, which is an oscillating motion by rotating the files in one direction and reversing their motion before making a complete rotation. The useful life of instruments can be increased with reciprocating motion with better resistance to cyclic fatigue than continuous rotation. The traction and compression strengths on instruments have been suggested as a disadvantage in different investigations, which occur in instruments with continuous rotation. Is there an ideal instrument?