The regeneration of the periodontium can be distinguished from many other regenerative processes because of the periodontium's extremely limited endogenous regenerative capability. Additionally, regeneration of the periodontium involves the regeneration of at least three unique tissues and their complex structures. Recent evidence suggests that periodontal ligament retains its regenerative capacity to different degrees throughout adulthood which is attributed to the remaining progenitor/stem cells within the periodontium that maintain their proliferation and differentiation potential and the...