The epithelial cell rests of Malassez--a role in periodontal regeneration?

This article reviews general aspects about the epithelial cell rests of Malassez (ERM). The historical and general morphological features of the ERM are briefly described. The embryological derivation of the ERM is presented as an important consideration in understanding the events associated with their origin and possible functional roles within the periodontal ligament. The ultrastructural description of the ERM is also included to complement the morphological characteristics which distinguish these cells as the unique epithelial element of the periodontal ligament. The unique ability of these cells to synthesize and secrete a number of proteins usually associated with cells of mesenchymal origin, rather than ectodermal origin, is discussed in light of their role in cementum repair and regeneration. Such considerations lead to our hypothesis that one of the functional roles of the ERM may lie not only their role in maintaining and contributing to the normal periodontal cellular elements and function but also contributing, in a significant manner, to periodontal regeneration.