Improved bone regeneration using collagen-coated biphasic calcium phosphate with high porosity in a rabbit calvarial model

Many growth factors have been paired with synthetic bone grafts to accelerate the healing process in vivo. Collagen has been particularly examined as a mediator of the enhancement of bone regeneration. This study investigated the new bone formation potential of micro-macroporous biphasic calcium phosphate (m-BCP), high porosity biphasic calcium phosphate (p-BCP), and collagen-coated p-BCP (cp-BCP) using a rabbit calvarial defect model. At 2 or 8 weeks after surgery, bone tissue was collected. The three-dimensional analysis of new bone formation using synchrotron radiation micro-computed tomography and histological study were conducted. The new bone formation values observed at 2 and 8 weeks in the negative control, m-BCP, p-BCP, and cp-BCP groups were 11.21 ± 1.36 mm3, 21.75 ± 1.18 mm3, 24.59 ± 1.26 mm3, and 29.54 ± 2.72 mm3, respectively, and 18.34 ± 3.99 mm3, 32.27 ± 3.78 mm3, 43.12 ± 1.61 mm3, and 58.20 ± 3.84 mm3, respectively. New bone formation was greatest in the cp-BCP group, while the amount of new bone at 8 weeks was higher than at 2 weeks in each group. The use of cp-BCP to enhance new bone formation during the healing period could improve bone regeneration.