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Updated: Jun 19, 2026

Scanning Electron Microscopic Evaluation of Surface Defects of Remover Retreatment File After Single and Multiple Uses
Published on: October 11, 2024
[Cleanliness of the root canal walls after preparation with Mtwo rotary nickel-titanium instruments: a SEM study]
Damian Lichota1, Alicja Nowicka, Krzysztof Woźniak
1Zakład Stomatologii Zachowawczej Pomorskiej Akademii Medycznej w Szczecinie, Szczecin.
Introduction:
The aim of this study was to evaluate the cleanliness of the walls of root canals following their preparation using Mtwo nickel-titanium rotary instruments.
Material And Methods:
The study was performed on 5 mesial roots of mandibular molars and 3 buccal roots of maxillary molars with moderate curvatures. The canals were instrumented using Mtwo nickel-titanium rotary files powered by the endodontic micromotor to a size 30/.05. During instrumentation FileEze was used as a lubricant and after each instrument the canals were irrigated with solution of natrium hypochlorite. The final flushing was performed with distilled water and the canals were dried. The roots were splitted longitudinally into halves and prepared for SEM observation. Debris and smear layer were evaluated in the apical, middle and coronal parts of the root canal walls using a 5-point scales proposed by Hülsmann et al. Established data were analysed statistically.
Results:
Evaluation of debris revealed in high number of scores 1. Evaluation of the removal of the smear layer revealed in smaller amount of it in coronal parts of the root canals (scores mainly 3 and 4) and in greater amount in apical parts (scores mainly 4 and 5).
Conclusion:
It was found that under the conditions of the present study Mtwo instruments successfully removed debris, although they left canal walls covered with smear layer.
