Shaping ability and cleaning effectiveness of Mtwo versus coated and uncoated EasyShape instruments in severely curved root canals of extracted teeth
- 28 January 2011
- journal article
- research article
- Published by Wiley in International Endodontic Journal
- Vol. 44 (5), 447-457
- https://doi.org/10.1111/j.1365-2591.2011.01850.x
Abstract
To compare the cleaning effectiveness and shaping ability of Mtwo, PVD-coated and uncoated EasyShape nickel-titanium rotary instruments during the preparation of curved root canals in extracted human teeth. A total of 60 root canals of mandibular and maxillary molars with curvatures ranging between 25° and 35° were divided into three groups of 20 canals. Based on radiographs taken prior to instrumentation with the initial instrument inserted into the canal, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared using a low-torque control motor according the single-length technique. Using pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. Preparation time, changes of working length and instrument failures were also recorded. These data were analysed statistically using ANOVA and Student-Newman-Keuls test. The amounts of debris and smear layer were quantified on the basis of a numerical evaluation scale. The data established for scoring the debris and the smear layer were recorded separately and analysed statistically using the Kruskal-Wallis test. During preparation, one coated and two uncoated EasyShape files fractured. Completely clean root canals were never observed. All instruments maintained the original canal curvature well with no significant differences between the different instruments (P > 0.05). Instrumentation with Mtwo files was significantly faster than with the two other instruments (P < 0.05). For debris removal Mtwo instruments achieved significantly better results (P < 0.001) than the two EasyShape instruments. The use of coated EasyShape files resulted in significantly less debris compared to instrumentation with uncoated EasyShape instruments (P < 0.05). The results for remaining smear layer were similar and not significantly different for the coronal, middle and apical third of the canals (P > 0.05) but in summary significantly less smear layer was observed following instrumentation with Mtwo (P < 0.01). Under the conditions of this study, all instruments maintained the original canal curvature well. The use of Mtwo instruments resulted in good canal cleanliness. PVD-coating of EasyShape instruments had no impact on their shaping ability but improved their cleaning effectiveness.This publication has 53 references indexed in Scilit:
- Cyclic fatigue of NiTi rotary instruments in a simulated apical abrupt curvatureInternational Endodontic Journal, 2010
- Mechanical response of nickel–titanium instruments with different cross‐sectional designs during shaping of simulated curved canalsInternational Endodontic Journal, 2009
- Canal transportation and centring ability of RaCe rotary instrumentsInternational Endodontic Journal, 2009
- Cleaning and shaping curved root canals: Mtwo;vs ProTaper;instruments, a lab comparisonIndian Journal of Dental Research, 2009
- Influence of shaft design on the shaping ability of 3 nickel-titanium rotary systems by means of spiral computerized tomographyOral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2008
- Development and sequelae of canal transportationEndodontic Topics, 2006
- Cyclic fatigue resistance and three‐dimensional analysis of instruments from two nickel–titanium rotary systemsInternational Endodontic Journal, 2006
- Surface debris of canal walls after post space preparation in endodontically treated teeth: a scanning electron microscopic studyOral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2004
- Appearance of the root canal walls after preparation with NiTi rotary instruments: a comparative SEM investigationClinical Oral Investigations, 2004
- Light and scanning electron microscopic evaluation of Glyde™ File Prep in smear layer removalInternational Endodontic Journal, 2003