Abstract: Vibrations for application to hard living tissue, such as bones, teeth, etc., are derived from a magnetostrictive element disposed in a varying electromagnetic field to create dimensional variations in the magnetostrictive element. In an audiodontic vibrator for the hearing impaired, a magnetostrictive rod is disposed in the hollow core of an electromagnetic coil through which current flows in response to acoustic signals. The resulting electromagnetic field in the core passes through the magnetostrictive rod, causing small dimensional variations in the rod corresponding to amplitude variations in the field. An actuator in contact with the rod extends from the housing and transmits the dimensional changes as low amplitude vibrations to the hard tissue via a bracket mounted on a tooth by an adhesive resin-based cement. The bracket has a receiving channel contoured to slidably and removably receive the distal end of the actuator in close fitting frictional relation.

Abstract: Waterborne acoustic signals are received and processed into electrical driver signals to energize a transducer held in selectively controllable vibration-transmitting engagement with a tooth of an underwater diver. The transducer converts the electrical signals into low amplitude sound-associated vibrations imparted to the tooth, through the jawbone and scull to the cochlea for processing into electrical signals carried to the brain and perceived as intelligible sound. The addition of conventional broadcast means permits two-way underwater communication. The transducer can be labially or occlusively mounted, preferably against an upper or maxillary tooth and the force of engagement between the transducer and the tooth is at least partially controlled by the diver to optimize communication characteristics.