The periodontal ligament-periosteum sandwich hypothesis: A thought experiment on fenestrations and dehiscences.

This article describes a hypothesis for bone recovery after iatrogenic dehiscences or fenestrations. When roots are moved out of the alveolar bone, the periodontal ligament and periosteum form a bilayer membrane (sandwich) over the exposed root. If the root is allowed to relapse back toward its original position, bone recovery will occur between the periodontal ligament and periosteum.