Guided tissue regeneration--why, when and how?

Chronic periodontitis results in the destruction of the collagen fibre attachment to cementum, apical migration of the epithelial attachment, contamination of the exposed root surface by plaque and loss of alveolar bone. Regeneration can be defined as the restitution of lost tissues to a state which existed before destruction. As such, it is an ultimate and ideal goal and in most circumstances is currently beyond our capabilities. However, research in periodontology over the last 10 years or so has made considerable advances and is perhaps unique in proposing a new and fundamental treatment modality--guided tissue regeneration.