Influence of the thickness of mineral trioxide aggregate on sealing ability of root-end fillings in vitro

The purpose of this study was to compare the ability of different thicknesses of mineral trioxide aggregate (MTA) to prevent apical leakage through the use of a protein-dye complex with Coomassie Brilliant Blue G. Sixty-four teeth were divided into 4 groups, then filled with MTA to depths of 1, 2, 3, or 4 mm. Two teeth served as the positive controls. Another 2 teeth served as the negative controls. Root-filled teeth were mounted in an apparatus and then challenged with protein solution. The evaluation was conduced at 24-hour intervals for 60 days. The 1-mm-thick MTA was the least effective in preventing apical leakage (P < .05). No significance difference was found between 2- and 3-mm-thick MTA (P > .05). Four-millimeter-thick MTA was significantly more effective than the other thicknesses tested (P < .05). The results of this study suggest that the thickness of 4 mm is most adequate for the use of MTA as a root-end filling material.