Effectiveness of xenogeneic and synthetic bone-block substitute materials with/without recombinant human bone morphogenetic protein-2: A preclinical study using a rabbit calvarium model.

Abstract

To investigate new bone (NB) formation by using bone-block substitute materials with/without recombinant human bone morphogenetic protein-2 (rhBMP-2). Three synthetic bone-block substitute materials [biphasic calcium phosphate (BCP); nanostructured hydroxyapatite (NH); 3D-printed tricalcium phosphate/hydroxyapatite (3DP)] and one xenogeneic deproteinized bovine bone mineral (DBBM) block substitute were affixed to rabbit calvarium using osteosynthesis screws, either with rhBMP-2 (n=12) or without rhBMP-2 (n=16). At 2 or 12weeks (n=6 with rhBMP-2 and n=8 without rhBMP-2 for each week), histologic, histomorphometric and microcomputed tomography analyses were performed. The application of rhBMP-2 increased NB formation in all experimental groups at both weeks. DBBM resulted in a greater area of NB compared with synthetic blocks either with or without rhBMP-2 at 2weeks (2.8±0.9 vs. 1.4±0.5-1.9±1.4mm2 ; 1.4±1.0 vs. 0.6±0.3-0.9±0.5mm2 ) and without rhBMP-2 at 12weeks (3.0±0.8 vs. 1.7±0.7-2.6±1.5mm2 ) (p>0.05). NB formation did not differ significantly for DBBM and the three types of synthetic block with rhBMP-2 at 12weeks (4.5±2.0 vs. 3.8±0.7-5.1±1.1mm2 ; p>0.05). rhBMP-2 enhanced NB in all blocks. DBBM blocks yielded more NB than synthetic blocks without rhBMP-2. The application of rhBMP-2 appears to compensate for differences in late healing.