Rotary electric toothbrushes encompass a number of different designs but are all similar because they each have a set of rotating bristles. The bristles are either arranged in a circular format that rotates or oscillates or the individual tufts or bristles contained in the brush head each possess a spinning motion. More often than not, these brushes generate between 3,000 and 7,500 brush strokes per minute. Rotary brushes compose a huge percentage of all electric toothbrushes sold today.