Mechanical debridement and biofilm removal from periodontally diseased root surfaces form an integral part of initial periodontal therapy. This is usually achieved with traditional hand instruments, sonic-, ultrasonic, or oscillating scalers. Aim of this study was the clinical investigation of a novel ultrasonic device (Vector, Duerr, Bietigheim, Germany) with a new approach of creating ultrasonic vibration, compared to scaling and root planing with hand instruments for non-surgical periodontal therapy. 14 patients were treated using either the Vector device or manual scaling and root planing in this controlled, prospective split-mouth study. 3 months after treatment probing depth and degree of inflammation were reduced in both groups, with relevant differences between the two groups. However, a significant gain of clinical attachment was found in the Vector-group. Schlagwörter: chronische Parodontitis, Scaling und Wurzelglättung, Handinstrument, Vector-System