Abstract
Complete removal of smear layer and debris during the process of root canal therapy is of paramount importance in order to achieve the objectives of endodontic treatment. The aim of this study was to compare the amount of extruded debris and smear layer using two widespread rotary nickel-titanium instruments. Fifty eight freshly extracted human mandibular first molar mesial canals were randomly assigned into two groups. The root canals were instrumented using Mtwo (VDW, Munich, Germany), and BioRaCe (FKG Dentaire, LaChauxde-Fonds, Switzerland) NiTi instruments. Debris and smear layer from the apical thirds part during instrumentation were evaluated by scanning electron microscope. Then, the scores of remaining debris and smear layer were calculated for each group and compared. Data were then statistically analyzed using Mann-Whitney U test. There were significant differences in the amount of smear layer among two groups (P extruded by the BioRaCe group and the least by the Mtwo group. The results of the present study showed that, although both instrumentation techniques apically extruded debris and smear layer through the apical foramen, the Mtwo instruments induced less extruded debris and smear layer than the BioRaCe rotary systems.
Highlights
Recent advances in the field of endodontics have led to the use of nickel titanium (NiTi) rotary instruments in dental practice
Smear layer differs from the dusty pattern of superficial debris in that it is a layer of muddy material, composed of an amorphous layer of organic-inorganic debris, and bacteria, which is compacted against the dentine walls due to the rasping action of endodontic instruments [6,7]
Within the parameters of this study, the use of Mtwo files resulted in significantly less smear layer compared with canal preparation of BioRaCe instruments, whereas in terms of debris no statistically significant differences were apparent
Summary
Recent advances in the field of endodontics have led to the use of nickel titanium (NiTi) rotary instruments in dental practice. Canal preparation is less arduous and more standardized by using NiTi in instrument manufacture and the introduction of high torque rotary handpieces. Rotary instrumentation with NiTi files results in a more uniform preparation with regard to taper and can enhance obturation by providing resistance [9,10]. The basic series (standard set) of Mtwo rotary files includes four instruments with variable tip sizes ranging from no. Based on the related description, the aim of this investigation was to compare the cleaning efficiency (residual debris, and the smear layer) after preparation of severely curved root canals with Mtwo, and BioRaCe files
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