An orthodontic appliance audio receiver injects sound into the head and ear cavities of the wearer using vibration, e.g., mandibular (or skull) vibration. Using mandibular vibration, the wearer hears the audio source noiselessly, effortlessly, and without disturbing others, yet provides themselves with entertainment or other audio information. The orthodontia metalwork may be used to form an antenna. Hearing audio (e.g., music) by `feeling` vibrations from the orthodontic appliance audio receiver encourages a patient to wear their prescribed orthodontia, improving and/or expediting the overall orthodontic therapy. A wireless (or even wired in low cost applications) audio signal receiver is built-in to a retainer, together with a transducer and a power source such as a battery, allowing unlimited transfer of information directly into the wearer's head through their mouth. An appropriate RF transmitter device worn or carried by the user may include a local point-to-point transmitter or a local wireless network device (e.g., a BLUETOOTH piconet), in combination with any audio source (e.g., CD player, cassette player, digital fixed medium player such as an MP3 player, etc.). Alternatively, the RF transmitter may relate to a conventional radio station transmitter.