Dental hearing aid gets approved in Europe Published duration 16 March 2011

image caption Once placed in the mouth, the device becomes almost invisible

A new hearing aid that transmits sound through a person's teeth has been approved for use in Europe.

The device, called SoundBite, directs sound through the jawbone and into the inner ear.

It is placed onto the upper left or right molars and is custom-made for each patient.

The Royal National Institute for Deaf People (RNID) warned that it may not be suitable for everyone with hearing problems.

Bone conduction

While conventional hearing aids use air conduction to increase the volume of sound travelling through the air, SoundBite uses a different approach - bone conduction.

First, a network of mini microphones placed behind the impaired ear pick up the sound in the environment and cancel out the noise.

The sound is transmitted wirelessly to the prosthetic in the mouth.

The device sends the vibrations through the teeth and bones directly to the cochlea - the auditory part of the inner ear - bypassing the middle and outer ear.

This way it can help those who are deaf in one ear to hear in stereo.

The company that makes the system, Sonitus Medical, said that the mechanism is the first ever non-surgical device to use bone conduction.

UK reception

There are around nine million deaf or partially deaf people in the UK alone.

According to the RNID, only six million of them require a hearing aid - and out of those six million, only about two million actually wear one.

Many do not like the look of it, and there are those who find it difficult to convince their GP to prescribe one, said Angela King, RNID senior audiology adviser.

image caption Around 2 million people in the UK use a hearing aid.

And there are no guarantees that the new device will enjoy a warm reception in the UK, she added.

"Just by looking at it, you can't imagine it being very comfortable.