BPA-free resin-modified calcium silicate cement with enhanced bioactivity and biocompatibility

To evaluate physicochemical properties, bioactivity and biocompatibility of experimental resin-modified calcium silicate cements (Rm-CSCs) formulated with BPA-free monomers (FUDMA and UDMA), in comparison with a BisGMA-based counterpart and commercial Rm-CSCs (TheraCal LC and BioCal-CAP).

Experimental FUDMA-, UDMA-, and BisGMA-based Rm-CSCs were synthesized at a 3:5:2 mass ratio (resin matrix: tricalcium silicate: zirconia oxide). Calcium ion release and pH changes were tested over 28 days. Degree of conversion, water sorption, and solubility were assessed. Apatite-forming ability was examined after 28-day immersion in simulated body fluid (SBF) or culture medium. Cytotoxicity was determined using a CCK-8 assay with human dental pulp cells, and initial pulp response was assessed using a vital human tooth model. Data were analyzed using one-way ANOVA or Kruskal-Wallis test followed by Tukey's HSD test (α = 0.05).

All materials exhibited alkaline pH and sustained calcium ion release. Degree of conversion of FUDMA-, UDMA- and BisGMA-based formulations were 65.86%, 67.68% and 57.48%, respectively (p > 0.05). Water sorption of FUDMA- (36.22 μg/mm³) and UDMA-based cements (40.80 μg/mm³) were significantly lower than that of BisGMA-based counterpart (91.59 μg/mm³) (p < 0.05). Following SBF immersion, apatite-like calcium phosphate was formed for FUDMA-based version, other materials formed calcium carbonate as the main crystalline phase. Rm-CSCs were all cytocompatible, except TheraCal LC reduced cell viability to 42.60% (p < 0.05). Pulps capped with all Rm-CSCs maintained a well-organized morphology with no necrosis after 2 weeks.

Within the limitation of this study, the FUDMA-based formulation exhibited favorable physicochemical properties, biocompatibility and bioactivity.