Micro-CT evaluation on osteoconductivity of DCPD-coated β-TCP granule using experimental rats

β-tricalcium phosphate (β-TCP) bone substitutes have been widely used because of its excellent tissue response and good osteoconductivity. However, recent study reported that the osteoconductivity of β-TCP could be enhanced by treating β-TCP surfaces with saturated acidic calcium phosphate solution. In this study, the osteoconductivity of treated β-TCP granule were evaluated using micro-computed tomography (micro-CT) scan technique. The granule specimens were obtained by exposing β-TCP granules with saturated acidic calcium phosphate solution for 10, 30 and 60 mins, respectively. Then, critical bone defect size with dimension of 9 mm were made at rat calvarial, and the defect was reconstructed with 10, 30 and 60 mins treated β-TCP granules and β-TCP granules without treatment as a control. After 2 and 4 weeks implantation, the specimens with the surrounding bone tissue were taken out and examined using micro-CT machine. Based on the cross section of micro-CT images, new bone formations were observed from the edge of the defect towards the center of the bone defect area in all specimens. At 2 weeks, new bone formations were observed for 10 min and 30 min treated β-TCP granules when compared with other specimens. The 30 min treated β-TCP granules showed faster new bone formation rate after 4 weeks implantation. It can be concluded that 30 min treated β-TCP granules revealed the highest osteoconductivity in comparison to the other specimens.