Development of hard tissue inductive calcium phosphate root canal filling materials containing mucopolysaccharide

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An equimolar mixture of tetracalcium phosphate and dibasic calcium phosphate-2 hydrate were selected for the solid phase of bio-active cement. The mixture has buffer action of the solid phase. This mixture is kneaded with buffer solution including low concentration of citric acid. Sodium chondroitin sulfate was included in this liquid phase. In hardening process, the pH value of this cement showed 8.4-8.5. The pH value of neutral region might suggest biocompatibility of this cement.The result of in vivo experiment showed that the cement cause no inflammatory reaction. This cement including chondroitin sulfate might promoted the hard tissue formation. Hard tissue was added in root canal wall just under the cement applied on the amputated pulp surface. The root canals were ultimately closed. The cement was experimentally extruded in periapical tissue via the apical foramen. The cement in defected alveolar bone was absorbed immediately. Reconstruction of alveolar bone with absorption of cement was recognized.In this study, calcium phosphate cement was kneaded in low concentration of citric acid solution. In hardening reaction of low concentration of citric acid solution and calcium phosphate particles, calcium phosphate particles coagulate mutually. Hydroxyapatite constructing the hardened cement shows low crystallinity. In vivo experiment in subcutis, macrophages and multinucleated giant cells were observed around the cement in setting process. These cell should accumulated to phagocytose calcium phosphate fine particles.It was considered that improvement required in setting time and/or hardening reaction of the cement. On the other hand, it is a fact that this cement is bioresorvable material because of the low crystallinity. It is considered that this cement is effective for bone reconstruction.