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

Abstract

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 16weeks of healing. 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 16weeks post-operatively. 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±0.60mm2 [mean±standard deviation] in groups1-4, respectively; bone-to-implant contact: 9.44±11.51%, 19.91±15.19%, 46.31±29.82% and 42.58±26.27% in groups1-4, respectively). The osteogenic efficacy of BMP-2 on the regeneration of peri-implant bone defects was not detectable after 16weeks regardless of the carrier materials.