Increased new bone formation with a surface magnesium-incorporated deproteinized porcine bone substitute in rabbit calvarial defects.

This study investigated the effects of magnesium ion (Mg) incorporation into the surface of deproteinized porcine cancellous bone in the bone healing of rabbit calvarial defects with the expectation of utilizing the integrin-ligand binding enhancement effect of Mg, and compared its bone healing capacity with that of untreated porcine cancellous bone and deproteinized bovine bone (Bio-Oss). Hydrothermal treatment was performed to produce Mg-incorporated porcine bone using an alkaline Mg-containing solution. The surface morphology and chemical composition of the samples were investigated using scanning electron microscopy, energy-dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. Defects 7 mm in diameter were created in the calvaria of 14 adult male New Zealand White rabbits and were filled with (1) untreated porcine bone (PB), (2) Bio-Oss, and (3) Mg-containing porcine bone (MG). The percentage of newly formed bone (NB%) was evaluated histomorphometrically at 2 and 4 weeks after implantation. Hydrothermal treatment resulted in a Mg-containing surface in porcine bone covered with nanostructures ~100 nm in size. The MG group supported better new bone formation compared with the other groups. Osteoconductive new bone formation was observed in the central defect area in the MG group at an early healing time-point. Histomorphometric analysis revealed significantly greater NB% in the MG group when compared with the untreated PB and Bio-Oss groups at 4 weeks (p < 0.05). The Mg-incorporated porcine bone with surface nanostructures achieved rapid new bone formation in the osseous defects of rabbit calvaria compared with untreated xenografts of porcine and bovine origin.