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Alleviating fatigue and failure of NiTi endodontic files by a coating containing inorganic fullerene-like WS2 nanoparticles

Published online by Cambridge University Press:  04 May 2011

Adi Ram Adini
Materials and Interfaces Department, Weizmann Institute of Science, Rehovot 76100, Israel; and Faculty of Dental Medicine, Hadassah-Hebrew University, Jerusalem 91120, Israel
Yishay Feldman
Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
Sidney R. Cohen
Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
Lev Rapoport
Holon Institute of Technology, Holon 58102, Israel
Alexey Moshkovich
Holon Institute of Technology, Holon 58102, Israel
Meir Redlich
Faculty of Dental Medicine, Hadassah-Hebrew University, Jerusalem 91120, Israel
Joshua Moshonov
Faculty of Dental Medicine, Hadassah-Hebrew University, Jerusalem 91120, Israel
Boaz Shay
Faculty of Dental Medicine, Hadassah-Hebrew University, Jerusalem 91120, Israel
Reshef Tenne*
Materials and Interfaces Department, Weizmann Institute of Science, Rehovot 76100, Israel
a)Address all correspondence to this author. e-mail:
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Nickel-titanium (NiTi) alloys combine several remarkable characteristics, among them are shape-memory, superelasticity, great strain recovery, good biocompatibility, and corrosion resistance. These render them well suited to a wide range of medical applications, such as cardiovascular stents, laparoscopy, and dental applications such as NiTi endodontic files (EFs) used for root canal treatment, which are the focus of this work. Unfortunately, fatigue-induced and incidental failure of NiTi EFs is not uncommon, which may lead to severe medical consequences. Here we examine the effects of cobalt coatings with impregnated fullerene-like WS2 nanoparticles on file fatigue and failure. Dynamic x-ray diffraction, nanoindentation and torque measurements all indicate a significant improvement in the fatigue resistance and time to breakage of the coated files, stemming from reduced friction between the file and the surrounding tissue. These methods are possibly applicable to a variety of NiTi-based medical devices where fatigue and consequent failure are of relevance.

Copyright © Materials Research Society 2011

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