Prosthetic teeth could make great hearing aids.
Vibrations applied to replacements of missing teeth travel well through the jawbones to the inner earresearchers report in September Journal of the Acoustical Society of America. The finding could lead to discreet alternatives to conventional hearing aids and cochlear implants that hearing-impaired people often use (Serial number: 7/7/16).
Earlier tooth-based hearing aid designs clipped onto the molars and received sound wirelessly from a microphone placed behind the ear. Dental researcher Jianxiang Tao and his colleagues want to take the concept a step further, turning dental implants into hearing aids. The electronics that impart sound vibrations would be embedded in part of a false tooth anchored in the jaw, says Tao, of Tongji University in Shanghai.
But first, the team had to determine how well dental implants transmit sound compared to natural teeth and the mastoid bone behind the ear, which other types of hearing aids rely on to work. The researchers then applied sound tones to the implants, natural teeth and mastoid bones of 38 people with hearing loss and a single dental implant. For a wide range of frequencies, the volunteers could hear sounds through the implants as well as, or better than, through natural teeth or mastoid bones, the team reports.
Frontal dental implants seemed to work slightly better than dental implants toward the back of the jaw. That may be because the jaw at the front of the mouth is harder than the jaw at the back, the team speculates. The lower teeth and implants worked just as well as the upper ones in transmitting sound.
Compared with traditional hearing aids, hearing aids with dental implants may offer “excellent concealment, good comfort, and better sound quality,” the researchers write.