Topical themes

KILLING BACTERIA WITH ULTRASOUND

A root canal treatment is rarely a pleasant experience at the best of times. Unfortunately, bacteria can remain in the root canal, multiply and cause another infection, requiring a repeat visit to the dentist. Clearly, it is preferable to ensure that all bacteria are eliminated the first time around.

It is possible to avoid the need for successive root canal treatments by using ultrasonic vibrations to eradicate all bacteria. The dentist introduces a thin probe which then vibrates at an extremely high frequency, exciting the fluid within the root canal. The bacteria are 'rinsed out'.

Ultrasound
Researchers from the Physics of Fluids department are working to improve the techniques now used by dentists. They hope to do so by establishing the frequency at which the fluid is cleansed most effectively and exactly how deep the probe must be inserted into the root canal. Even a small improvement could greatly reduce the discomfort associated with this form of treatment and the need for repeat visits to the dentist.

All sound is caused by vibrations; they set up waves which travel through a medium. That medium can be air, but sound actually travels even better through fluids and solids. The human ear can detect sound at frequencies of between 20 and 20,000 Hertz, this being the number of vibrations per second. Sound at a frequency above 20 KHz is inaudible to humans and is known as 'ultrasound'.

Other projects of this research group
The researchers of the Physics of Fluids department are also using ultrasound to produce extremely detailed images of (cells within) the human department. For further information, see Medical Imaging.