GTR stands for "guided tissue regeneration". This technique is a flap operation to reproduce parodontal structures. After curettage the gingiva does not reattach to the cleansed root surfaces, because epithelial cells cover the wound area too rapidly after the removal of the diseased internal pocket walls. Parodontal structures (desmodont/alveola bone/cementum) cannot reform during this period.

This rapid downward growth of the epithelia along the internal pocket walls can be prevented. The first step is to form a gingival (mucosal) flap. Dental plaques and granulation tissue is removed in the same way as in deep scaling. A resorbable membrane is then placed over the parodontal defect. The mucogingival flap is repositioned and secured with sutures. A blood clot forms under the membrane. Normal wound healing will result in new parodontal structures. Epithelial depth growth is prevented by the membrane. It has dissolved after months (in the case of membranes consisting of resorbable material) or it must be removed after a few weeks (non-resorbable membranes).

A further regenerative measure is the insertion of bone substitute material. In this case root curettage is also performed under anaesthesia and the formation of a mucoperiosteal flap. Bone substitution material is then inserted into the intraalveolar bone pocket and then covered with the mucoperiosteal flap. The wound is supplied with a tight suture and dressing.

A dressing or parodontal pack is a special cover for the wound. A wound or parodontal pack protects the gingiva after larger parodontal procedures.