الفهرس 
AbstractOnly 14 pages are availabe for public view
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Abstract
Nickel–titanium (NiTi) technology was introduced to clinical endodontics nearly two decades ago. NiTi alloys reveal two distinctive features that are of relevance to clinical dentistry; which are, shape memory and superelasticity. Sterilization aims to destroy or impede reproduction of microorganisms including bacteria, spores, and fungi. Since microorganisms have been shown to be the major cause of endodontic pathology, sterilization of dental instruments is a mandatory step of the aseptic technique in endodontics. The research objects were to evaluate the effect of autoclaving, gamma radiation, and ultraviolet sterilization methods on the surface properties of NiTi rotary endodontic files manufactured by traditional and new twisted NiTi alloys. Based on the results and within the limitations of this study, it could be concluded that; despite being the most popular and effective method of sterilization, autoclave can induce surface defects of NiTi rotary endodontic instruments. Gamma radiation has less effect on surface properties of NiTi instruments compared with autoclaving. The application of ultraviolet radiation in sterilization of NiTi rotary endodontic files induces less effect on surface properties compared with autoclaving. Thermal treatment used for TF manufacturing results in increasing phase transformation temperatures compared with RS instruments manufactured with a traditional process.