Multi-strand spiral metal spring for use e.g. in orthodontics uses combination of shape memory and superelastic materials

摘要

The spring is made from twisted filaments of individual strands of material selected from the group comprising shape memory alloys, superelastic materials and combinations of these. The strands can be made from Ni/Ti alloys containing at least 50 per cent Ti and 40 per cent Ni by weight. The twisted filaments can be slid into a tube for insertion into the human body, and heat treated at 300 - 550 deg C for 1 - 15 sec after twisting to stabilize their shape.