Sydney, Aug 19 - Dentists can now size up the mineral content of tooth enamel non-invasively with the help of laser-generated ultrasound, says a new study.

This is the first time anyone has employed such a tool to find the elasticity of our teeth, besides assessing dental health and predict tooth decay and cavities.

Enamel goes through a cycle of mineral loss and restoration, through a lifetime, in which healthy teeth maintain a high mineral content.

If the balance between mineral loss and gain is lost, however, teeth can develop areas of softened enamel -- known as carious lesions -- which are precursors to cavities and permanently damaged teeth.

'The ultimate goal is to come up with a quick, efficient, cost-effective, and non-destructive way to evaluate the mineralisation of human dental enamel,' says study co-author David Hsiao-Chuan Wang, graduate student at the University of Sydney (U-S).

Wang and his adviser Simon Fleming, physics professor at the U-S Institute of Photonics and Optical Science, worked on the study with U-S dental researchers and ultrasonic researchers from National Cheng Kung University, Taiwan.