In Vitro Assessment of Mineral Trioxide Aggregate Setting in the Presence of Interstitial Fluid Alone

Introduction: The aim of this study was to determine the ability of white mineral trioxide aggregate (MTA) Angelus (Solucoes Odontologicas, Londrina, Brazil) to set in 24 hours within the root canal in the presence of an intrinsic moisture source (interstitial fluid) alone without the need for moist cotton pellet placement. Methods: Extracted teeth were used to simulate the open apex situation. MTA was placed to a depth of 4 mm and allowed to set for 24 hours in the following test groups: a current protocol group with a moist cotton pellet, a test group with no moist cotton pellet placement, and positive and negative control groups with varnished roots. The teeth were embedded in florist sponges immersed in fetal bovine serum at 13.3-kPa pressure. The MTA set was tested using the Vickers hardness test, and the data were analyzed using analysis of variance. Results: The greatest mean surface hardness values were observed in the current protocol group (80.7 +/- 35.6), but this was not statistically different when compared with the test group without a moist cotton pellet (78.3 +/- 53.7) or the control groups. Conclusions: Moist cotton pellet placement may not be essential for MTA setting in apexification procedures or situations in which the apical surface of the MTA is against a moist opening of greater than 1 mm. (J Endod 2013;39:402-405)