Mandibular reconstruction in the rabbit using beta-tricalcium phosphate (β-TCP) scaffolding and recombinant bone morphogenetic protein 7 (rhBMP-7) - Histological, radiographic and mechanical evaluations

This investigation assesses the histological, radiographic and mechanical properties of regenerated bone in a unilateral critical-size osteoperiosteal mandibular continuity defect in the rabbit model, following the application of beta-tricalcium phosphate (beta-TCP) scaffolding and recombinant human bone morphogenetic protein 7 (rhBMP-7). The study was carried out on nine cases; in six cases the critical-size defect was filled with rhBMP-7 in the beta-TCP scaffolding, and in three cases the beta-TCP was used alone. The cases were sacrificed 3 months post-operatively. Histologically the overall mean of the percentage of regenerated bone volume in the cases that received rhBMP-7 was 29.41% +/- 6.25%, which was considerably greater than the 6.35% +/- 3.08% in the cases treated with beta-TCP alone. Mechanical testing of the cases treated with rhBMP-7 gave failure moments (55 mNm-2.040 Nm) that were consistently greater than those treated with beta-TCP alone (0 mNm-48 mNm). In some cases the mechanical properties of the regenerated bone were comparable to those of untreated bone. RhBMP-7 in prefabricated beta-TCP scaffolding appeared, radiographically and histologically, to be an effective method for bone regeneration in mandibular critical-size defects in the rabbit model. This points towards possible future clinical applications. (C) 2012 European Association for Cranio-Maxillo-Facial Surgery.