Ridge augmentation using recombinant bone morphogenetic protein-2 techniques: an experimental study in the canine

Abstract

Background: The use of recombinant bone morphogenetic protein-2 (rhBMP-2) with a collagen carrier material has severe limitations in regards to space maintenance. The aim of this study was to test whether rhBMP-2 combinations with allografts or a mesh enhance the regeneration of missing bone and the subsequent placement of dental implants.

Methods: In five dogs, surgically created ridge defects were augmented using one of the following treatment modalities: 1) rhBMP-2/absorbable collagen sponge (ACS) under a titanium mesh (Mesh); 2) rhBMP-2/ACS plus canine freeze-dried bone allograft; 3) rhBMP-2/ACS plus canine demineralized freeze-dried bone allograft (DFDBA); or 4) rhBMP-2/ACS wrapped around a canine cancellous allograft block (Block Allograft). Eight weeks later, dental implants were placed in the augmented areas. The dogs were sacrificed 16 weeks after bone augmentation and specimens obtained for histologic and histomorphometric analyses.

Results: All sites augmented with DFDBA, and one site with Block Allograft did not allow placement of dental implants. In all other sites, dental implants were placed. The area of regenerated bone ranged between 23.40 mm(2) (freeze-dried bone allograft) and 35.16 mm(2) (Block Allograft). The greatest amount of bone was regenerated in the Block Allograft group ranging from 4.54 mm (at 1.5 mm), to 4.95 mm (at 3 mm), to 5.14 mm (at 4.5 mm). The least amount of bone was regenerated by the DFDBA group with values of 2.24 mm (at 1.5 mm), 2.84 mm (at 3 mm), and 3.34 mm (at 4.5 mm). Statistically significant differences were observed between DFDBA and block allograft at all three levels (P <0.001).

Conclusion: The combination of rhBMP-2 and a block allograft provides the greatest ridge width of the four treatment options used in this canine ridge augmentation model.