Comparative Microstructural and Chemical Evaluation of Pozzolan-Based MTAs and ProRoot MTA Using SEM, EDS, and FTIR

Aim: This study aimed to compare the microstructural and chemical characteristics of three available mineral trioxide aggregate (MTA)–based cements using scanning electron microscopy (SEM), energydispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR). Materials and Methods: ProRoot MTA, Endocem MTA, and Endocem Zr were evaluated. Samples were prepared in silicone molds, set at 37 °C for 24 hours, ground into powder, and stored at 37 °C under 100% humidity for 72 hours. SEM analyses were performed at magnifications ranging from ×1000 to ×20,000. EDS spectra were obtained from two randomly selected regions of each specimen. FTIR analysis was conducted over a wavenumber range of 400–4400 cm⁻¹. Results: SEM analysis demonstrated differences in surface morphology. ProRoot MTA showed small, uniformly distributed particles, indicating a homogeneous microstructure. Endocem MTA exhibited larger, irregular particles with a heterogeneous appearance, whereas Endocem Zr presented an intermediate particle size and a smoother surface. EDS confirmed calcium, silicon, and oxygen as major elements in all materials. Bismuth was detected in ProRoot MTA and Endocem MTA, while zirconium was identified exclusively in Endocem Zr. Minor elements including aluminum, magnesium, sodium, potassium, and iron were also observed. FTIR spectra revealed absorption bands related to Bi–O, Zr–O, Si–O–Si, Si–O–Ca, Ca–O, C–O, and Al–O bonds. Conclusion: Material-dependent microstructural and chemical differences were observed among pozzolan-based MTAs. Endocem Zr may be preferable in esthetically demanding cases, whereas ProRoot MTA may be favored when enhanced mechanical and physical properties are required.