Malocclusion refers to misalignment of the teeth or a mismatch between teeth of the upper and lower jaw. analyses of skeletons during historical times and of fossils from prehistoric times indicate that malocclusion was rare over much of human existence. we, like others mammalian species, evolved to have good physical alignment between teeth in the upper and lower jaws. in the last few hundred years, however, the incidence of malocclusion has increased dramatically in most parts of the world. this increased susceptibility to malocclusion is most likely due to