One gram of each MTA was digested using a mixture of hydrochloric and nitric acids and filtered. The As, Cr, and Pb in the resulting filtrates were analyzed by inductively coupled plasma–optical emission spectrometry. The level of Cr6+ was measured by the methods suggested in the Korean Standard L 5221. The results were statistically analyzed using the Mann-Whitney U test.
The concentration of As in ProRoot MTA was 1.16 ppm, but As was not detected in Ortho MTA. Cr6+ and Pb were not detected in either MTA. Ortho MTA contained significantly less Cr than ProRoot MTA (P < .05).
Ortho MTA and ProRoot MTA meet the ISO specification 9917-1 regarding the safety limits of As and Pb and are safe biomaterials when the purity of As, Cr6+, and Pb is considered.