Hydration and microhardness of mineral trioxide aggregate depending on ratio between di- and tricalcium silicates

Tricalcium silicate (C₃S) and dicalcium silicate (C₂S) are the main components related with the hydration process of mineral trioxide aggregates (MTAs) for endodontic materials. In this study, we investigate the influence of different ratios of C₃S and C₂S in a series of MTA samples with (100-x)C₃S-xC₂S-18ZrO₂ (x = 0, 10, 15, 34, and 100) on their physical and chemical characteristics, hydration process, and microhardness properties. The chemical compositional properties of different samples are measured using X-ray diffraction, X-ray photoelectron spectrometry, and scanning electron microscopy. The physical and microhardness properties are also investigated after the standard hydration process (ISO 6876:2021). Generally, the sample with higher C₃S ratio induces the faster hydration, which results in decreased fluidity as well as shorter working and setting times. The microhardness generally decreases with larger C₃S ratio.