The purpose of this study was to compare, in vivo, in 30 teeth destined for extraction, the abilities of the Scalex rotary bur system and Gracey curettes to obtain a smooth root surface. The time taken for each treatment was also evaluated. The profilometry results showed no significant differences between instruments with regard to roughness or working time, in single-rooted teeth, multirooted teeth, or in pockets of 5 mm or more. Only for distal longitudinal roughness and in pockets less than 5 mm did the Scalex system perform slightly better. There was some improvement in working time when the distal surfaces were instrumented with Scalex. Both systems demonstrated a similar capacity to render smooth surfaces.