Physicochemical, biological, and antibacterial evaluation of tricalcium silicate-based reparative cements with different radiopacifiers

Objective: To evaluate tricalcium silicate-based (TCS) experimental materials, associated with zirconium oxide (ZrO₂), calcium tungstate (CaWO₄) or niobium oxide (Nb₂O₅) radiopacifiers, in comparison with MTA Repair HP (Angelus).

Methods: Physicochemical tests: setting time, radiopacity, pH and solubility. In vitro assays: cytotoxicity: MTT and Neutral Red - NR; cell bioactivity: alkaline phosphatase activity (ALP), Alzarin red staining (ARS) and real time PCR (qPCR). Antibacterial activity: direct contact on Enterococcus faecalis in the planktonic form. Physicochemical and ARS data were submitted to ANOVA/Tukey tests; antibacterial activity, to Kruskall-Wallis and Dunn tests; MTT, NR, ALP and qPCR were analyzed by ANOVA/Bonferroni tests (α = 0.05).

Results: TCS + CaWO₄ presented the longest setting time and MTA HP the shortest. Except for TCS, all the materials presented radiopacity above 3 mmAl. The cements had alkaline pH, antibacterial activity, low solubility and no cytotoxic effects. The highest ALP activity occurred in 14 days, especially to TCS, TCS + ZrO₂ and TCS + CaWO₄. TCS + ZrO₂, TCS + Nb₂O₅ and MTAHP had higher mineralized nodule formation than those of the negative control (NC). After 7 days, there was no difference in mRNA expression for ALP, when compared to NC. However, after 14 days there was no overexpressed ALP mRNA, especially TCS + Nb₂O₅, in relation to the CN. All the materials presented antimicrobial action.

Significance: The pure tricalcium silicate associated with ZrO₂, CaWO₄ or Nb₂O₅ had appropriate physicochemical properties, antibacterial activity, cytocompatibility and induced mineralization in Saos-2, indicating their use as reparative materials.