In the present study root canal preparation in curved root canals in extracted teeth was compared using either the vibratory Self-Adjusting File (SAF) or the rotary BioRace NiTi system. The issues investigated were longitudinal and cross-sectional preparation shape, root canal cleanliness and the incidence of procedural mistakes. No significant differences were found with respect to the above-listed topics investigated in this study. Both NiTi systems can be recommended for clinical use. Keywords: BioRace, canal cleanliness, root canal preparation, Self-Adjusting File, shaping ability, working safety