A printed smile

A SET of straight and gleaming teeth makes for a beautiful smile. But how many people who have undergone a little dental maintenance know that they may have inside their mouths some of the first products of a new industrial revolution? Tens of millions of dental crowns, bridges and orthodontic braces have now been produced with the help of additive manufacturing, popularly known as 3D printing. Forget the idea of hobbyists printing off small plastic trinkets at home. Industrial 3D printers, which can cost up to $1m, are changing manufacturing.

The business of dentures shows how. For the metal bits in false teeth, dentists have long relied upon a process called “investment casting”. This involves creating an individual model of a person’s tooth, often in wax, enclosing it in a ceramic casing, melting out the wax and then pouring molten metal into the cavity left behind. When the cast is split open, the new metal tooth is removed. It is fiddly, labour-intensive and not always accurate; then again the casting method is some 5,000 years old.