Calcium silicate/calcium phosphate biphasic cements for vital pulp therapy: chemical-physical properties and human pulp cells response

Objectives The aim was to test the properties of experimental calcium silicate/calcium phosphate biphasic cements with hydraulic properties designed for vital pulp therapy as direct pulp cap and pulpotomy. Methods CaSi-αTCP and CaSi-DCDP were tested for ionreleasing ability, solubility, water sorption, porosity, ability to nucleate calcium phosphates, and odontoblastic differentiation— alkaline phosphatase (ALP) and osteocalcin (OCN) upregulation—of primary human dental pulp cells (HDPCs). Results The materials showed high Ca and OH release, high open pore volume and apparent porosity, and a pronounced ability to nucleate calcium phosphates on their surface. HDPCs treated with CaSi-αTCP showed a strong upregulation of ALP and OCN genes, namely a tenfold increase for OCN and a threefold increase for ALP compared to the control cells. Conversely, CaSi-DCDP induced a pronounced OCN gene upregulation but had no effect on ALP gene regulation. Conclusions Both cements showed high biointeractivity (release of Ca and OH ions) correlated with their marked ability to nucleate calciumphosphates. CaSi-αTCP cement proved to be a potent inducer of ALP and OCN genes as characteristic markers of mineralization processes normally poorly expressed by HDPCs. Clinical relevance Calcium silicate/calcium phosphate cements appear to be attractive new materials for vital pulp therapy as they may provide odontogenic/dentinogenic chemical signals for pulp regeneration and healing, and dentin formation in regenerative endodontics.