Phase Composition of ProRoot Mineral Trioxide Aggregate by X-Ray Powder Diffraction

Introduction: Composition and crystalline phases of the endodontic material mineral trioxide aggregate (MTA) is of fundamental importance for understanding its physical and chemical properties. This research was done to determine the composition of crystalline phases for ProRoot MTA. Methods: For phase identification, powder of ProRoot MTA was analyzed by x-ray diffraction (XRD), comparing the MTA peaks with the data contained in the Powder Diffraction File of the International Centre for Diffraction Data (ICDD). To help the task of identifying a phase, chemical analysis by energy-dispersive spectrometry (EDS) and particle-induced x-ray emission (PIXE) were applied. Quantitative phase analysis was performed by applying Rietveld refinement to the XRD data. Results: ProRoot MTA is composed of bismuth oxide (19.8%), tricalcium silicate (51.9%), dicalcium silicate (23.2%), calcium dialuminate (3.8%), and calcium sulfate dehydrated (1.3%). The trace elements detected were Fe, Ni, Cu, and Sr. Conclusions: Rietveld refinement was able to analyze the composition of ProRoot MTA, which is based basically on a mixture of Portland cement (with smaller quantities of calcium dialuminate and calcium sulfate dehydrated) and bismuth oxide for radiopacity. (J Endod 2009;35:875-878)