Binding Properties and Biocompatibility of Accelerated Portland Cement for Endodontic Use

Accelerated Portland Cement (APC) was obtained by the mixing of white mineral trioxide aggregate (WMTA), synthesised by sol-gel method, with an accelerator addition – CaCl2. APC has a rapid setting but lower values of the compressive strength developed after 28 days of hardening at 37oC (as compared with WMTA).The decrease of the compressive strength is due to the modification induced by CaCl2 presence in the binding system – both microstructure and composition are affected; large pores and micro cracks were assessed in the microstructure of APC pastes, opposite to the much denser WMTA microstructure. Moreover, given the high amount of CaCl2 used in this work (10% wt.), it is also possible the formation of a new hydrate phase i.e. calcium hydroxyl chloride. The APC biocompatibility, assessed by an in-vitro test (SBF soaking of APC powder) and cytotoxicity of APC specimen, hardened for 28 days, on Hep2 cells was very good.