[Guided tissue regeneration--the beginning of a new era in periodontal surgery]

The therapy of deep infrabony defects in periodontal diseases has been a great problem for decades both for dentists and their patients, as well. After application of classic therapy in patients with serious stages of periodontal diseases (subgingival curettage, Modified Widmann flap surgery with and without implantation of implants) a significant strengthening of teeth in alveolus was observed, as well as alleviation of patient's discomfort, and decrease of the depth of periodontal pockets, bleeding, inflammation, etc. However, in spite of the application of this therapy a postoperative defect was sometimes filled with different low tissues of periodontium, in other words periodont reparation took place. For this reason, recidives could happen, as well as gingival recession, inflammation, root resorption. At the beginning of the nineties a new principal was introduced in the therapy of periodontal diseases: Guided Tissue Regeneration. This principal includes a controlled action between four different species of periodontal tissue: gingival epithelium, gingival connective tissue, alveolar bone, and periodontal ligament. This is achieved by surgical placement of non resorbale or bioresorbable periodontal membranes, which are placed during flap surgery above the previously treated infrabony defect. With membranes placed in that way the periodontal defect is for some time phisically separated from epithelium and gingival connective tissue and in that way alveolar bone is regenerated, as well as periodontal ligament in other words restitutio ad integram takes place. Nowadays, two concepts of guided tissue regeneration can be considered: a concept of isolation and a concept of integration. The first concept includes application of non resorbable, most frequently synthetic, membranes (so-called E-PTFE polyterafluorethylene) which replace the mucoperiosteal flap into its original position. After six weeks a patient is subjected to one more surgical intervention when flap is raised again and the non resorbable membrane is removed. The second operation diminishes the value and partially discredits the application of non resorbable membranes. For this reason, the concept of integration is today more frequently applied, that is to say the application of bioresorbable membranes is nowadays very frequent. They are by their chemical composition poly D,L lactides and they provide membranes with ideal resorption properties. Of great importance is their property to stay unchanged for six weeks, and then to be resorbed by geometrical progression. As the membrane is resorbed, it is not necessary to remove it, so there is no need for another surgery, and that enables the process of healing to proceed undisturbedly. For this reason, the concept of integration is also called a Single Step Method.

On the basis of papers of the leading scientists from the field of guided tissue regeneration it can be concluded that by application of Single Step Method or in other words by application of bioresorbable membranes a tremendous progress was made in the therapy of infrabony periodontal defects. The application of these membranes is especially indicated in treating degree II furcation defects, then infrabony defects particularly with 2 and 3 walls and good results were also achieved in the therapy of a big problem in esthetic periodontology--gingival recession. A relatively low price, as well as simple application, biological compatibility and undisturbed process of healing of the wound are great advantages of the application of bioresorbable membranes, so in the near future their application on a large scale can be expected in the therapy of periodontal diseases, as well as further research work on their development, especially on their impregnation by growth factors, antibiotics, etc.