To remove the bacteria that cause periodontal disease hidden in gum pockets with a toothbrush, the bristle tips must reach into the narrow pockets. The Original Extra Fine Brush from Panasonic features bristle tips with a diameter of only about 0.02 mm, designed to reach exactly 3 mm into gum pockets. The brush vibrates at a rotational speed of approximately 31,000 strokes per minute, creating a fine brushing motion at high speed. Tiny high-speed vibrations thoroughly remove plaque from the gum pockets while minimizing stress on the teeth and gum edges.