Optimization of mineral trioxide aggregate formulation using Taguchi design and impedance analysis

This study aimed to optimize the composition of mineral trioxide aggregate (MTA) to improve its setting time and handling characteristics by applying the Taguchi L9 (34) orthogonal array design. The primary components of MTA—tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A)—were synthesized using a solid-state reaction method. The synthesized powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) to confirm their phase purity and microstructural features. To assess the influence of composition and water-to-cement (W/C) ratio on setting behavior, electrochemical impedance spectroscopy (EIS) was performed to monitor hydration progression in real time. The Taguchi method enabled the assessment of four factors (C3S, C2S, C3A, and W/C ratio) at three levels each, identifying the optimal formulation: C3S:2, C2S:1, C3A:3, and W/C:0.3. The cement prepared under these conditions was further sieved into three particle size ranges (≤38 µm, 38–75 µm, >75 µm) to analyze the effect of particle size on setting performance. The finest particle group exhibited the shortest setting time of 41 min. DSC and impedance results confirmed that smaller particle sizes and optimized composition promoted more efficient hydration. This study demonstrates that the combination of Taguchi design and impedance analysis offers an effective strategy for optimizing MTA formulations. The findings contribute to the development of high-performance dental cements with faster setting times and improved clinical usability.