a review of the various surface treatments of niti instruments

since the introduction of engine-driven nickel-titanium (niti) instruments, attempts have been made to minimize or eliminate their inherent defects, increase their surface hardness/flexibility and also improve their resistance to cyclic fatigue and cutting efficiency. the various strategies of enhancing instrument surface include ion implantation, thermal nitridation, cryogenic treatment and electropolishing. the purpose of this paper was to review the metallurgy and crystal characteristics of niti alloy and to present a general over review of the published articles on surface treatment of niti endodontic instruments.