The influence of radiopacifying agents on the physical and biological properties of tricalcium silicate-based cement

This study evaluated the influence of different radiopacifying agents on the physical and biological properties of tricalcium silicate-based cement (TCS). Eight radiopacifiers-bismuth oxide (Bi₂O₃), zirconium oxide (ZrO₂), calcium tungstate (CaWO₄), barium sulphate (BaSO₄), tantalum oxide (Ta₂O₅), strontium fluoride (SrF₂), strontium titanate (SrTiO₃), and barium titanate (BaTiO₃)-were incorporated into TCS, with pure TCS serving as the control. Setting time, compressive strength, radiopacity, discolouration, fluid uptake, porosity, solubility, bioactivity, calcium ion release, pH, and cytotoxicity were evaluated. Most radiopacifiers reduced the initial setting time and solubility without significantly affecting the final setting time, compressive strength at 7 and 28 days, bioactivity, or pH. All radiopacifiers increased radiopacity and calcium ion release, while also increasing fluid uptake and porosity. Certain radiopacifiers were associated with increased cytotoxicity. Among the materials tested, BaTiO₃ achieved the highest composite score. In contrast, CaWO₄, BaSO₄, ZrO₂, SrTiO₃, SrF₂, and Ta₂O₅ demonstrated progressively inferior performance compared with pure TCS, with Bi₂O₃ showing the least favourable outcome.