Objectives: To compare the cleaning efficacy and the long-term effect on gingivitis of a powered toothbrush with three-dimensional brush head action (Braun Oral-B 3D Plaque Remover D15) and a high-speed 'microtation' brush with an additional 'microbrush®-clip' (Rowenta Dentasonic MH921S). Material and methods: 80 healthy subjects took part in this controlled single blinded parallel study. Subjects were randomised by subject number. The two groups were bal-anced and stratified by gender, gingival index, smoking status and electric toothbrush use. A standard toothpaste was provided and no additional hygiene devices were al-lowed.Clinical assessments of all soft and hard tissues, attachment levels, probing pocket depths, gingivitis and plaque were performed at baseline and repeated 12 weeks later. Results: After 3 months compared to baseline, the median relative gingivitis reduction (upper;lower quartile) in the D15-group over all was 7.7% (-3.4;19.0) and in the Denta-sonic-group -1.2 (-16.2;9.1) the difference between the two groups being highly signifi-cant (p=0.005). The highest differences between both toothbrushes were found at both buccal and lingual surfaces with a gingivitis reduction of 16.6% (-3.7;19.7) for the D15 and -3.4 (-22.1;17.8) for the Dentasonic (p=0.0005). Conclusions: The D15 reduced the gingival index significantly, whereas there was no reduction detected in the Dentasonic group. Any signs of adverse reactions were neither reported nor detected. Keywords: gingivitis, hygiene, powered toothbrushes