Clinical and histological findings in guided bone regeneration (GBR) around titanium dental implants with autogeneous bone chips using a new resorbable membrane

The aim of this study was to test the value of a polydioxanon-membrane (PDS(R), Ethicon, Norderstedt, Germany) in combination with autogenous bone as a spacer for guided bone regeneration of denuded implant surfaces in comparison to simple augmentation. Altogether, in 8 Beagle dogs of 12 months, the three mandibular premolars were extracted on both sides and, after an uneventful healing of the extraction sockets in each mandibular site, two seize defined bone defects were produced. The defects were 7 mm long, had a vertical extension of 7 mm, and were 7 mm deep. These also included, therefore, the resection of the lingual cortical bone wall. In the center of all these 32 bone defects, Branemark fixtures with a diameter of 3 mm and a length of 10 mm were implanted. Every implant was primarily stable due to the fixation in the native bone under the created defects. In each mandible site, one bone defect was filled with autologous bone resulting from the previous defect preparation. Half of the defects were covered with a PDS membrane, and the other half were covered only by the relocation of the mucoperiosteal flap. During the observation period of 90-180 days, continuous clinical and radiological controls were executed. Aside from the observed clinical healing problems in the test sites, such as exposure of the membranes and serious inflammatory reactions, the histological and radiological results of the control group regarding bone regeneration were superior to these of the test group, which were valid also for the subgroups with or without autologous bone fillings. (C) 2000 John Wiley & Sons, Inc.