Effect of accelerants on the immediate and the delayed sealing ability of mineral trioxide aggregate when used as an apical plug: An in vitro study

AIM: To evaluate and compare the influence of various accelerators, 15% disodium hydrogen phosphate (Na(2)HPO(4)), 10% calcium chloride (CaCl(2)) and 23.1 wt% calcium lactate gluconate (CLG), on the immediate (after 72 h) and delayed (after 2 months) sealing ability of white ProRoot mineral trioxide aggregate (WMTA) when it is used as an apical plug. MATERIALS AND METHODS: Eighty, single-rooted mandibular premolars were instrumented and standardized artificial open apices were created. The samples were then randomly assigned into four experimental groups and two control groups. WMTA was mixed with the respective accelerators and an apical plug of 4-mm thickness was fabricated. The remaining canal spaces were then backfilled. The samples were stored for the stipulated time periods and then immersed in 0.2% Rhodamine B solution for 72 h. Dye leakage was analyzed using a stereomicroscope. RESULTS: Mean microleakage values of all experimental groups revealed that MTA + 23.1 wt% CLG showed the least leakage, followed by MTA + 15% Na(2)HPO(4) and MTA + 10% CaCl(2) with MTA + deionized water showing the maximum leakage at both the time intervals (P < 0.001). All the samples stored for a period of 2 months showed less leakage as compared with the samples stored for 72 h (P < 0.05). CONCLUSIONS: It was found that all three accelerators significantly accelerated the set of WMTA, of which 23.1 wt% CLG showed the best results, followed by 15% Na(2)HPO(4) and 10% CaCl(2). The sealing ability of all the experimental groups was significantly superior after 2 months as compared with that after 72 h.