Nitinol!

[elfs]

I loved Omni magazine as a kid, the slick Penthouse-for-Science Fiction readers that Bob Guccione published back in the 80s. One of the best articles, one of the few that sticks in my mind, was about the state-of-the-art in metamaterials, and how weird alloys and structured metals were going to change various industries. I was fascinated by the properties of nitinol, a metal that can be forged into different shapes and different temperatures, and will return to those shapes when exposed to other temperatures in a similar range. The magazine was full of the usual futuristic raves about all the interesting uses for this new technology.

Kouryou-chan's braces are made with nitinol. Apparently, the wire is cooled to room temperature, inserted into the mounts on the molars, then fitted to the rest of the appliance and locked down. As the metal warms up to body temperature, it contracts and exerts the force necessary to bring the teeth into line. Different weights of nitinol wire are used throughout the lifespan of the therapy to moderate the force on her teeth as they get closer and closer to their proper alignment.

Now that's kinda cool. I'm living in my own future.