The PC-based materials had the same constituents plus bismuth carbonate (JCPDS 01-073-6504) and MTA-Angelus had bismuth oxide (JCPDS 01-076-1730).
Alternative materials, including bismuth carbonate and others, have been proposed to substitute bismuth oxide (6); therefore, bismuth carbonate was chosen as the radiopacifying agent for this study.
PC-based groups had higher setting time than MTA-Angelus and increased proportionally with the amount of bismuth carbonate, which was also observed by other studies (21, 22).
The obtained results showed that the PC associated with 0 wt%, 2 wt% and 5 wt% bismuth carbonate did not have the required radiopacity to meet the criteria of an endodontic material.
Results for the cell viability assays showed no statistical-ly significant differences between the tested materials and negative control group for both 24- and 48-h experimental periods, suggesting that the addition of bismuth carbonate up to a 15 wt% concentration to PC is biocompatible and not damaging to HPDL cells.
The results of the present study demonstrated that the ad-dition of 15 wt% of bismuth carbonate to Portland cement did not result in sig-nificant changes to its physicochemical properties when compared to MTA-Angelus, except for the setting time, while maintaining cell viability and proliferation, and inducing min-eralisation and new bone formation.