US Patent 6918154 Toothbrush with longitudinal and lateral motion conversion

A toothbrush has a number of rotatable brush assemblies mechanically linked so as to move together with a handle. Each rotatable brush assembly includes a wheel, with radially projecting bristles, configured to rotate about an axis which is roughly parallel to a plane of contact with the teeth. The axis of rotation is inclined relative to a primary direction of insertion of the toothbrush, corresponding to an extensional direction of the handle, by an angle of between about 15° and about 75°, and preferably closer to 45°.