Comparative Evaluation of the Bone Regenerative Potential of a Novel Calcium Silicate-Modified Calcium Carbonate Graft Material: Histological and Micro-Computed Tomography Assessment Using a Rat Calvarial Defect Model

In the present study, we evaluated the usefulness of a porous sintered calcium carbonate body with CaSiO₃ by comparing its osteogenic capacity with that of calcium carbonate without CaSiO₃ and that of β-tricalcium phosphate (TP). A cranial defect model of eight-week-old male Wistar rats was divided into three groups: calcium carbonate (CC), calcium carbonate-CaSiO₃ composite (CC+CS), and TP. Micro-computed tomography (CT) and histological analysis were performed at four and eight weeks postoperatively. Upon quantitative evaluation of newly formed bone volume by radiography, the CC+CS group demonstrated the highest value at eight weeks postoperatively and exhibited significantly more new bone formations than the CC group (<i>p</i> < 0.05). Upon histological evaluation, the CC+CS group demonstrated significantly higher new bone formation than the CC group (<i>p</i> < 0.05). Furthermore, in terms of residual graft material ratio, at eight weeks postoperatively, the amount of residual graft material in the CC+CS group was significantly higher than that in the TP group (<i>p</i> < 0.05). Therefore, the addition of CaSiO₃ enhances the functional regulation of calcium carbonate-based artificial bone and can be incorporated in bone graft materials.