Regenerative effect of calcium phosphate glass cement in rabbit calvarial defect

Abstract

Various therapeutic methods for achieving bone regeneration have been proposed and bone grafting technique is one of the proposed methods. Amongst graft material, autogenous bone is regarded as a `gold standard` but there is limitation which require additional surgical site and result in ankylosis and root resorption of the adjacent teeth. Allogenic and xenogenic materials have no limitation of the amount but the risk of disease transmission. However, alloplastic graft material doesn`t have above mentioned limitations and many researches have been ongoing about alloplastic material. Amongst alloplastic material, calcium phosphate(CP) is not only chemically similar to bone tissue, but also has distinguished osteoconductive potential and good biocompatibility. Calcium phosphate glass(CPG), a type of CP, have solubility and that feature allows plasticity Moreover, the reaction to bone tissue of CPG can be modified by control of composition and crystallinity. The objective of this study is to evaluate of the bone regeneration effect of the newly developed calcium phosphate glass cement(CPGC) in rabbit calvarial defect. Twelve NewZealand white rabbits were used and three circular defects of 8mm diameter were created in rabbit calvaria. Groups were divided according to graft materials and healing period. Two defects were filled with either BCP made of 70% HA and 30% β-TCP(Positive Control) or CPGC(Experimental Group). The one remaining defect was unfilled, serving as the Control. The animals were sacrificed following 4 weeks and 8 weeks healing periods. In regards of the augmented area, groups grafted with alloplastic materials are larger than control group. BCP and CPGC showed favorable space maintaining capacity. At 4weeks, CPGC group demonstrated less bone formation than BCP group, that being statistically significant, but at 8weeks the difference in the new bone area between both groups was insignificant. This observation means bone formation rate of CPGC is initially slow but increases at a specific time. At 4 and 8 weeks, resorption of CPCC is greater than BCP. This can be explained with Ca/P ratio. In conclusion, newly developed CPGC demonstrated good space maintaining capacity and it is needed to improve bone formation capacity within the limits of this study.