Optimization of Components Formulation for MTA Cement Using Taguchi Method

Objectives: This study optimizes the composition of mineral trioxide aggregate (MTA) using the Taguchi method to improve its setting time and handling properties. The effects of tricalcium silicate (C₃S), dicalcium silicate (C₂S), tricalcium aluminate (C₃A), and the water-cement (W/C) ratio were analyzed to determine an optimal formulation.
Methods: Major MTA constituents (C₃S, C₂S, and C₃A) were synthesized via the solid-state method and characterized using XRD, SEM, and DSC analyses. The Taguchi L9 (3⁴) orthogonal array was employed to systematically evaluate the effects of C₃S, C₂S, and C₃A, and W/C ratio on setting time. Impedance analysis was used to monitor hydration behavior and correlate resistance changes with setting progression. The optimized cement composition (C₃S: 2, C₂S: 1, C₃A: 3, W/C: 0.3) determined through the Taguchi method was further evaluated by sieving into three particle size ranges (≤38 μm, 38–75 μm, >75 μm) to assess the impact of particle size on setting time.
Results: XRD confirmed the successful synthesis of single-phase compounds, while SEM revealed irregular plate-like structures with particle sizes below 30 μm. DSC analysis indicated prolonged exothermic activity in C₃S and C₂S, whereas C₃A reacted rapidly within 20 min. Impedance analysis provided a detailed analysis of the hydration process, showing distinct resistance changes for each component, which enabled accurate setting time determination. The optimized composition (C₃S: 2, C₂S: 1, C₃A: 3, W/C: 0.3) achieved a setting time of 41 minutes in the finest particle group (≤38 μm), significantly shorter than conventional MTA, which generally takes over two hours. The decrease in particle size further contributed to the acceleration of the setting process.
Conclusions: Impedance analysis effectively measured setting time, confirming the optimized cement composition determined via the Taguchi method. This approach provides a reliable strategy for fine-tuning MTA formulation, offering valuable insights for the development of high-performance dental materials.