Longitudinal study of the microleakage of two root-end filling materials using a fluid conductive system

A comparison of the microleakage of mineral trioxide aggregate (MTA) and a high copper admix amalgam (Valiant PhD) in root-end preparations was made using a fluid conductive device. Thirty-three bilaterally matched pairs of extracted, single-rooted teeth were prepared and obturated using lateral compaction of gutta-percha. The root-ends were resected and 3-mm-deep class I cavity preparations were made. The root-end preparations were filled with either amalgam or MTA. Guttapercha coronal to the root-end fillings was removed leaving only the amalgam or MTA present as a barrier to fluid movement. In the fluid-conductive device, the root canals were filled with a phosphate-buffered saline solution at a pressure of 10 psi. The flow of fluid was measured and compared at 1, 2, 3, 4, 8, 12, 16, 20, and 24 wk. The results showed amalgam to have significantly higher microleakage after 4 wk and higher variability compared with the MTA group.