About 900 years ago in China humans developed overbites, previous skulls showed biting edges that aligned, more like apes. The same happened in Europe about 250 years ago. The change was too abrupt to be evolutionary, and the times lined up with the adoption of chopsticks (and the precutting of food to suit) in China and the adoption of knife and fork in Europe. The muscles in our jaws need exercise to develop, like any other muscle. Weakness in these muscles, (experiments support) lead to overbites. https://www.businessinsider.com/using-cutlery-has-changed-the-human-face-2015-3?r=US&IR=T That may mean if we raised our young on a tougher diet with out cutlery most of that overtbite would not develop and our facial structure would look quite different. And an even less chewy diet would exaggerate the overbite further, over timescales much shorter than evolution takes effect, i,e. It would be a developmental structural change variable if being reversed, not a genetic hereditory change.