In recent years a new technique in periodontal surgery, known as guided tissue regeneration, has been developed in Scandinavia and the USA. After raising a flap and debriding the root surface, an inert membrane is placed between the flap and the underlying tissues. This allows the periodontal ligament to regain some of the connective tissue attachment lost during the disease process, something which has been unobtainable until now. The purpose of this paper is to review the area of periodontal reattachment and to introduce the new technique of guided tissue regeneration.