An electric toothbrush having a detachable brush head assembly including a driven shaft that is driven by a driveshaft disposed with in a housing. The driveshaft is part of or secured to a torsion bar that supports an armature including a pair of magnets. An electric coil receives an alternating flow of current at a predetermined frequency that causes the magnets to be alternately attracted to the coil and causes the torsion bar to oscillate in an oscillatory rotary motion.