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...http://www.google.com/patents/US6760945?utm_source=gb-gplus-sharePatent US6760945 - Acoustic toothbrush
