Comparison of Dimensional Changes of NanoZnO with Pulp Dent and AH26

In root canal treatment, the sealing of the root canal system after cleaning and shaping is absolutely necessary. According to the Grossman criteria, dimensional stability is among the requirements for a sealer. The aim of this study was to compare Nano-zinc oxide eugenol sealer with AH26 and Pulp Dent in terms of dimensional stability. In this research, for investigating the volume changes in sealers while setting, the three groups of ten sealers, including AH26 (DENTSPLY company made in Switzerland), Pulp Dent (PULP DENT company), and NanoZOE, were placed in a calibrated pipette with the accuracy of 0.001 bent at U-shaped. There was a certain volume of sealer within the set containing water and methylene blue in the incubator at 37°C, and then, the samples were read every 15 min at the first and second hours after mixing, every 20 min during the third hour, as well as after 24 h, a week, and 30 days. In general, AH26 had a minimal level of changes over time. Pulp Dent had little dimensional changes until 90 min, but from 90 min up to a week, Pulp Dent had the highest level of dimensional changes. NanoZOE had the highest level of changes up to 90 min, and then, it had dimensional changes more than AH26 and less than Pulp Dent up to a week. At the end of one month, there was no significant difference between the experimental groups regarding dimensional changes. After one month, the least and highest levels of dimensional changes were reported for AH26 and Pulp Dent. However, generally, the differences between the experimental sealers were not significant.