Histological findings in guided bone regeneration (GBR) around titanium dental implants with autogenous bone chips...

The aim of this study was to test the value of the new polydioxanone-membrane (PDS, Ethicon, Norderstedt, Germany) in combination with autogenous bone as a spacer for guided bone regeneration of denuded implant surfaces compared to simple augmentation. Forty implants were selected for 20 test cases (with membrane) and 20 control cases (without membrane) and were distributed randomly in 19 patients who were treated according to a standard protocol and examined. The defects were filled with autogenous bone chips, harvested interforaminally or locally, and were covered by the PDS membrane within the test group (control group: periosteum). The membranes were fixed with Memfix screws and cover screws. Seven membranes became exposed and were removed before reentry. Within the control group, three augments were sequestered. After 6 months, reentry was performed, the healing results were observed clinically, and biopsies were taken. The test group, including the seven cases with early removal of the membrane, showed that bone had filled in the defects in 95% of test cases, compared with 60% for the control group. The results of this study show that single augmentation of defects exceeding 9 mm2 is not sufficient. The membrane used in this investigation may be helpful for guided bone regeneration (GBR) at denuded screw thread sites in implant dentistry.