Objectives: The aim of the present study was to evaluate the sealing ‎ability of experimental nano sealers (nano calcium hydroxide and nano ‎bioactive glass) and to compare it with the commercial AH plus sealer ‎using a dye penetration method. ‎
Materials and methods: ‎
Sixty single-rooted mandibular premolars were selected. The coronal ‎portion of each tooth was removed to standardize root length at 16 mm ‎and the root canals were prepared with NiTi rotary files (ProTaper Next) ‎up to X4 (40/0.06). Teeth were randomly assigned and divided ‎according to the sealer used for obturation into three groups of 20 each. ‎Group I: AH plus, Group 2: Nano calcium hydroxide and Group 3: ‎Nano-bioactive glass. All root canals were obturated using single cone ‎gutta-percha(#40/.06) and one of the tested sealers. Root canal sealing ‎was assessed by a dye penetration test. The data were statistically ‎analyzed by ANOVA test followed by post hoc analysis (P < 0.05).‎
Results:‎
Significant improvement shown by the presented study suggests that ‎nano calcium hydroxide sealer showed significantly less dye leakage ‎than nano bioactive glass sealers and Ah plus sealer.‎

Conclusion: ‎
The results of this study showed that the synthesized nano-powder ‎sealers are suitable for use in root canal therapy to prevent leakage.‎
The root canal can be sealed better by using smaller nano-powder ‎particle sizes. In addition, the two groups exhibited significant ‎differences in leakage in comparison with commonly used AH plus ‎sealer.‎