This tiny string has a big impact.

A protein that quietly suppresses tooth growth may hold the key to regrowing teeth in adults, according to a line of research that has moved from mouse models to the doorstep of human clinical trials.

Many of us will lose an adult tooth in our lifetimes, whether through disease or misadventure – a punch that landed, a skateboarding trick that didn’t, say. And if you join these ranks, which include ...