THE EFFECT OF FLAP MANAGEMENT AND BIORESORBABLE OCCLUSIVE DEVICES IN GTR TREATMENT OF DEGREE-III FURCATION DEFECTS - AN EXPERIMENTAL-STUDY IN DOGS

The present experiment on guided tissue regeneration had 2 objectives namely: (i) to study if an improved anchorage of the soft tissue flaps during the initial healing period after membrane placement would redu ce the tendency for soft tissue recession and allow for healing of als o large furcation defects; (ii) to determine if the use of biodegradab le membranes in GTR procedures may promote new attachment formation in degree III furcation defects. 2 experiments were performed which incl uded 5 and 8 dogs each. In each animal, the 3rd premolar of the left o r right side of the mandible was selected as test site using the contr alateral tooth as control. 2 months prior to the start of the experime nt, the 2nd and 4th premolars in each side of the mandible were extrac ted. The extractions were performed to create a large edentulous space mesial and distal to the 3rd premolar. During GTR therapy the incisio ns prepared in this edentulous region were used to allow proper suture retention and flap stability during the initial phase of healing. In study 1, furcation defects (degree III) were prepared and subsequently treated according to GTR using e-PTFE membranes in the test and no me mbrane in the control site. In study 2, a bioresorbable membrane (Reso lut (R)) was installed in the test and an e-PTFE membrane in the contr ol sites. The nonresorbable membranes were removed after 30 days. The animals were sacrificed 5 months after reconstructive surgery, biopsie s were harvested, sectioned and analyzed histologically for new connec tive tissue attachment and bone. The results demonstrated that compara tively large furcation defects can be successfully regenerated by GTR therapy provided the membrane-covering soft tissue flaps are prevented from receding apical of the furcation fornix during healing. Our find ings also disclosed that a biodegradable membrane provides a barrier w hich is equally effective as a non-degradable teflon membrane in a GTR procedure.