[Guided bone regeneration around dental implants using a bioabsorbable membrane. A pilot investigation in...

The aim of this experimental investigation was to evaluate the effect of guided bone regeneration around immediately placed implants using different barrier membranes. Five adult fox hounds were used in this investigation. After extraction of all premolars in the lower jaw, implant osteotomies in the regions of the former premolars and additional buccal bone defects (5 mm x 5 mm) were created. Subsequently, the implants were placed. The defects were treated with one of the following three modalities: (a) guided bone regeneration, using a bioinert expanded polytetrafluoroethylene membrane, (b) no membrane application and (c) guided bone regeneration, using a bioabsorbable membrane made from a synthetic copolymer of lactide and glycolide. After a healing period of six months, the animals were sacrificed and the implants with the surrounding tissues processed for histologic evaluation. The clinical pretreatment defects between the different treatment groups were not statistically different (bioinert membrane group: 4.8 mm; control group: 4.3 mm; bioabsorbable membrane group: 4.9 mm). The remaining histological defects after a healing period of 6 months amounted to 3.2 mm for the nonresorbable group, to 5.6 mm for the control and to 6.3 mm for the bioabsorbable group. A significant difference was observed between the bioinert membrane group and the other two groups. The mineralized bone-to-implant contact in the bioinert membrane group was 52%, in the control group 47% and in the bioabsorbable membrane group 43.3%. The values were not statistically significant different. The results of this study indicate that a partial bone regeneration with bioinert e-PTFE membranes around immediately placed implants is possible. The utilized bioabsorbable polylactide/polyglycolide membrane did not show any bone regenerative effect, and the results did not differ from the control group without membrane application.