The power toothbrush includes a toothbrush body and a stem portion extending from the toothbrush body which has a workpiece with a flexible membrane at a remote end thereof, and a flexible membrane at a near end thereof as well. A movable piston is positioned in the stem portion, as well as a fluid which is in communication with the flexible membrane at the workpiece end of the toothbrush and the flexible membrane at the near end of the stem portion. The body includes a solenoid coil which, when actuated, moves the piston in opposing directions in a controlled manner within the stem, which acts on the fluid in the stem and moves the flexible membrane at the workpiece in and out at a desired frequency and amplitude.