Physicochemical characteristics of mineral trioxide aggregate depending on the ratio of di- and tricalcium silicates

Mineral trioxide aggregate (MTA) has gained attention as a bioactive endodontic material used for root-end filling, root repair, pulp capping, and iatrogenic root perforations, owing to its biocompatibility, high strength, and good sealing ability. Herein, physicochemical properties of MTA depending on the ratio of tricalcium silicate (C₃S) and dicalcium silicate (C₂S) was examined. A series of calcium silicate mixtures CSM of (100–x)C₃S-xC₂S (x = 0, 10, 14, 25, and 100) were prepared with 18 wt.% ZrO₂ addition. The pH of the hydrated CSM samples in Dulbecco’s modified Eagle’s medium (DMEM) solvent were increased to 10.7–12.1 from 7.55 of free DMEM, primarily owing to Ca(OH)₂ production during setting reaction of C₃S and C₂S. The solubilities of the hydrated CSM samples in deionized water were examined; the samples with high C₂S content exhibited relatively low solubility mainly due to the longer setting time and smaller amount of Ca(OH)₂ produced by C₂S setting reaction compared to C₃S. The flow of the CSM samples was measured by thickness of the hydrated samples under 120 g (ISO 6876:2012), which decreased with increasing C₂S content, which indicates that higher C₂S contents enhance penetration ability and workability of the MTA.