[Cleanliness of the root canal walls after preparation with Mtwo rotary nickel-titanium instruments: a SEM study].

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.