Bone cement with a modified polyphosphate network structure stimulates hard tissue regeneration

Abstract

In this study, a calcium polyphosphate cement (C pPC) consisting of basic components was investigated to assess its potential for hard tissue regeneration. The added basic components for improving the structural stability, which controlled the setting time, where the setting reaction resulted in the formation of amorphous structure with a re-constructed polyphosphate. Moreover, the characteristics were controlled by the composition, which determined the polyphosphate structure. C pPC exhibited outstanding dissolution rate compared with the common biodegradable cement, brushite cement (2.5 times). Despite high amounts of dissolution products, no significant cytotoxicity ensued. Induction of calcification in MG-63 cells treated with C pPC, the level of calcification increased with increasing C pPC dissolution rate. Induced calcification was observed also in C pPC-treated ST2 cells, in contrast with MG-63 and ST2 treated with brushite cement, for which no calcification was observed. In vivo tests using a rat calvarial defect model showed that resorbed C pPC resulted in favorable host responses and promoted bone formation. Additionally, there was a significant increase in defect closure, and new bone formation progressed from C pPC mid-sites as well as defect margins. From these results, C pPC exhibits significant potential as biodegradable bone substitute for bone regeneration.