Use of a Collagen Membrane Loaded With Recombinant Human Bone Morphogenetic Protein-2 With Collagen-Binding Domain for Vertical Guided Bone Regeneration

Background: Vertical bone regeneration of severe atrophic alveolar ridges remains a challenging procedure in implant dentistry. Methods: The aim of this study, accordingly, is to use a rabbit vertical guided bone regeneration model to evaluate whether using a collagen membrane (CM) loaded with small doses of recombinant human bone morphogenetic protein-2 with collagen-binding domain (rhBMP-2/CBD) would enhance two-way vertical bone regeneration. In each of eight rabbits, four titanium cylinders were screwed in perforated slits made into the external cortical bones of the calvaria. The following four treatment modalities were randomly allocated: 1) cylinders filled with mineralized bone matrix and covered with CM/rhBMP-2/CBD; 2) cylinders filled with mineralized bone matrix and covered with CM/rhBMP-2; 3) cylinders filled with mineralized bone matrix and covered with CM alone; or 4) cylinders filled with mineralized bone matrix without a membrane cover. Results: After 6 weeks, the new bones were examined by histologic analysis. Slender new bone trabeculae were observed in the superficial layer of the titanium cylinders covered with CM/rhBMP-2/CBD, and higher degrees of bone were observed in this group compared with the other three groups. The average area fraction of newly formed bone was significantly more in the CM/rhBMP-2/CBD group compared with the CM/rhBMP-2, CM, or the no membrane control groups (all P < 0.01). Conclusions: The present study demonstrates that CMs loaded with small doses of rhBMP-2/CBD induce new bone formation not only from the surface of the native bone, but also from the superficial structures. The augmented new bone, therefore, is improved in both quantity and quality.