Research Paper: Comparison efficacy of calcium hydroxide removal by Revo-s, Protaper Rotary file from root canal

Abstract Introduction: The aim of this study was to evaluate the efficacy of two rotary instrument systems (ProTaper and Revo-s File) in removing calcium hydroxide residues from root canal walls Materials and Methods:Thirty human  maxillary incisors were instrumented with the ProTaper System up to the F2 instrument, irrigated with 2.5% NaOCl,and filled with a calcium hydroxide intracanal dressing. After 7 days, the calcium hydroxide dressing was removed using the following rotary instruments:G1 - NiTi size 25, 0.06 taper, of the Revo-s  File System; G 2 - NiTi size 25, 0.06 taper, of the protaper File System. The teeth were longitudinally grooved on the buccal and lingual root surfaces, split along their long axis, and their apical and cervical canal thirds were evaluated by SEM (×1000). Results: The images were scored and the data were statistically analyzed using the Kruskall Wallis test. None of the instruments removed the calcium hydroxide dressing completely, either in the apical or cervical thirds, and no significant differences were observed among the rotary instruments tested (p > 0.05). Conclusion:To achieve the best adaptation of filling material after root canal treatment, it is crucial to remove intracanal medication from the root canal walls. However, none of the irrigation regimens and different techniques were able to completely remove the CH from the root canal wall.