Rotary root canal nickel-titanium (NiTi) instruments are particularly suitable for preparation of curved root canals. Numerous NiTi systems are available. The RaCe system, with design features such as short, twisted cutting edges alternating with straight debris transporting spaces, promises good results. In addition, RaCe files require less torque and higher rotational speed. Other design features, like sharp cutting edges and electrochemical surface treatment, increase the cutting efficiency and reduce the number of instruments needed.
Keywords: crown-down technique, NiTi instruments, RaCe system, rotary root canal treatment