Osteogenic efficacy of BMP-2 mixed with hydrogel and bone substitute in peri-implant dehiscence defects in dogs: 16 weeks of healing

Objectives: The objective of this study was to determine the effect of bone morphogenetic protein-2 (BMP-2) mixed with either polyethylene glycol hydrogel or synthetic bone substitute (SBS) on new bone formation in peri-implant dehiscence defects after 16 weeks of healing. Materials and methods: A guided bone regeneration procedure was performed in box-type peri-implant defects that were surgically prepared in six beagle dogs. The following four experimental groups were used (i) control (no graft), (ii) SBS+hydrogel, (iii) SBS+BMP-2/hydrogel and (iv) BMP-2/SBS+hydrogel. Volumetric analysis using micro-computed tomography and histomorphometric analysis was performed at 16 weeks post-operatively. Results: The amount of new bone and the total augmented volume did not differ significantly between both BMP-treated groups and the SBS+hydrogel group (p >.05). Likewise, no histometric differences were observed in the values of new bone area and bone-to-implant contact ratio among the three augmentation groups (new bone area: 0.06 ± 0.08, 0.19 ± 0.20, 0.48 ± 0.37 and 0.56 ± 0.60 mm² [mean ± standard deviation] in groups 1–4, respectively; bone-to-implant contact: 9.44 ± 11.51%, 19.91 ± 15.19%, 46.31 ± 29.82% and 42.58 ± 26.27% in groups 1–4, respectively). Conclusion: The osteogenic efficacy of BMP-2 on the regeneration of peri-implant bone defects was not detectable after 16 weeks regardless of the carrier materials.