Medicine: Engineering Dentures

An estimated 37 million Americans, just under a quarter of the population, wear false teeth (i.e., upper or lower plates, or both), and about 10 million more use partial dentures. For the great majority, regular removable plates are sufficient, but others find ordinary false teeth uncomfortable and irritating. For these "denture neurotics" one possible solution is a feat of tiny-scaled civil engineering known as the dental implant, i.e., fastening the denture to the jawbone to hold it in place permanently.

Dozens of implant techniques were tried over the years but most failed because...