EVALUATION OF A BIOABSORBABLE PHYSICAL BARRIER FOR GUIDED BONE REGENERATION - PART II - MATERIAL AND A BONE-REPLACEMENT GRAFT

Part I of the evaluation of a prototype bioabsorbable physical barrier composed of a copolymer of lactide and glycolide for treatment of bon e defects in the guided bone regeneration procedure indicated that the prototype bioabsorbable physical barrier did not possess sufficient s pacemaking characteristics to prevent collapse of the barrier into the defect or against the threads of the titanium implants. The purpose o f Par? ii was to evaluate this bioabsorbable physical barrier in combi nation with a supporting material to prevent barrier collapse. Posteri or mandibular teeth in three dogs were extracted and allowed to heal f or 3 months. This produced localized alveolar ridge defects with a nar row buccolingual width. Six titanium threaded implants were placed in the right and left mandibles of each dog so that nonspacemaking dehisc ence-type defects were produced. Two defects in each animal were rando mly treated with the prototype bioabsorbable physical barrier and deca lcified freeze-dried bone allograft: two defects were treated with a n onbioabsorbable expanded polytetrafluoroethylene barrier with decalcif ied freeze-dried bone allograft: and one defect each, was treated with prototype bioabsorbable physical barrier alone or by flap access with no barrier or bone replacement graft. The results demonstrated that b oth the bioabsorbable and the nonbioabsorbable barrier combined with d ecalcified freeze-dried bone allograft produce comparable amounts of n ew bone with percent bone-to-implant contact height width and area. De fects treated with the prototype bioabsorbable physical barrier alone or no barrier demonstrated unfavorable results. if is suggested that a bone replacement graft is indicated when treating defects with a nons pacemaking morphology.