The adjunctive effect of rhBMP-2 on the regeneration of peri-implant bone defects after experimental peri-implantitis.

Objectives: The aim was to evaluate the degree of bone regeneration and re-osseointegration attained when combining a xenogeneic bone replacement graft plus rhBMP-2 and a collagen membrane in ligature-induced peri-implantitis osseous defects in dogs.

Material And Methods: Thirty-six implants were placed in a total of 6 Beagle dogs, 3 months after tooth extraction. Once experimental peri-implantitis was induced, defects were randomly allocated into two treatment groups: in the test group guided bone regeneration was applied using de-proteinized bovine bone mineral with 10% collagen soak loaded with rhBMP2 covered with a natural collagen membrane. In the control group, the same scaffold and membrane were used but saline was used to soak the grafting material. After a period of 8 weeks of healing, a submerged environment clinical measurements were taken and histological outcomes were evaluated once the animals were euthanized. Histological bone defect regeneration (BR) was considered as the primary outcome variable, and dog was selected as the unit of analysis.

Results: Partial defect resolution was observed in both treatment groups. The histometric analysis showed a higher degree of bone regeneration for the test group, although differences were not statistically significant, both in terms of histological bone gain and percentage of re-osseointegration.

Conclusions: (a) The addition of rhBMP2 to a bovine xenograft/collagen vehicle carrier failed to provide a significant added value in terms of bone regeneration or re-osseointegration, (b) partial re-osseointegration of a previously contaminated surface was achieved, although (c) a complete defect resolution and re-osseointegration to the level previous to the induction of the disease failed to occur in any of the treatment groups.