A new device has been invented by Professor Brian Millar which is designed to cancel out the noise of the dentist's drill, thereby reducing some patients' anxiety about dental treatment.

The prototype for the device works in a similar way to noise-cancelling headphones but is designed to deal with the very high pitch of the dental drill. Patients would simply unplug their headphones, plug the device into their MP3 player or mobile phone, then plug the headphones into the device, allowing them to listen to their own music while completely blocking out the sound of the drill and suction equipment. The patient can still hear the dentist and other members of the dental team speaking to them but other unwanted sounds are filtered out by the device.

Professor Millar, of King's College London's Dental Institute, was initially inspired by carmaker Lotus' efforts to develop a system that removed unpleasant road noise while still allowing drivers to hear emergency sirens. Then with over a decade of collaboration with engineering researchers the prototype has been designed, built and successfully evaluated.

The device uses technology called 'adaptive filtering' where electronic filters lock onto sound waves and removes them, even if the amplitude and frequency change as the drill is being used.

'The beauty of this gadget is that it would be fairly cost-effective for dentists to buy,' said Professor Millar. 'What we need now is an investor to develop the product further, to enable us to bring this device to as many dental surgeries as possible.'