Mechanical debridement and biofilm removal from periodontally diseased rootsurfaces form an integral part of initial periodontal therapy. This isusually achieved with traditional hand instruments, sonic-, ultrasonic, oroscillating scalers. Aim of this study was the clinical investigation of aultrasonic device (Vector, Duerr, Bietigheim, Germany) with a new approachof creating ultrasonic vibration, compared to scaling and root planing withhand instruments for non-surgical periodontal therapy. 14 patients weretreated using either the Vector device or manual scaling and root planing inthis controlled, prospective split-mouth study. 3 and 6 months aftertreatment probing depth and degree of inflammation were reduced in bothgroups, with relevant differences between the two groups. However, asignificant gain of clinical attachment was found in the Vector-group. Schlagwörter: periodontitis, periodontal therapy