Washington, Aug 20 - A study has revealed that the structure of tooth enamel holds promising clues for aerospace engineers as they build planes and space vehicles of the future.

Herzl Chai of Tel Aviv University (TAU) School of Mechanical Engineering, who led the study with George Washington University, said: 'Teeth are made from an extremely sophisticated composite material which reacts in an extraordinary way under pressure.'

The researchers applied varying degrees of mechanical pressure to hundreds of extracted teeth, and studied what occurred on the surface and deep inside them.

'Teeth exhibit graded mechanical properties and a cathedral-like geometry, and over time they develop a network of micro-cracks which help diffuse stress. This, and the tooth's built-in ability to heal the micro-cracks over time, prevents it from fracturing into large pieces when we eat hard food, like nuts.'

The automotive and aviation industries already use sophisticated materials to prevent break-up on impact. For example, airplane bodies are made from composite materials -- layers of glass or carbon fibres -- held together by a brittle matrix.