Teresa Roberta Tripi

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OBJECTIVES This study was designed to verify whether nitridation treatment of the cutting surfaces resulted in surface or subsurface changes that produced an increase in the resistance to wear in nickel titanium (NiTi) endodontic files. STUDY DESIGN Some experimental samples were exposed to ionic implantation by using 150 keV of nitrogen ions and doses of(More)
INTRODUCTION The purpose of this study was to compare the shaping ability of ProTaper, Mtwo, BioRaCe, and BioRaCe + S-Apex instruments in simulated canals with an S-shaped curvature. METHODS Canal transportation and aberrations were assessed by comparing the preinstrumentation and postinstrumentation images under a stereomicroscope. Analysis of variance(More)
OBJECTIVE A comparative study of the fatigue resistance of rotary nickel-titanium endodontic instruments was performed with the aim of assessing the influence of both instrument design and surface treatment on flexural fracture. STUDY DESIGN To evaluate fatigue resistance of different rotary instruments, a total of 120 instruments were tested; these came(More)
The present work analyzes possible increases in resistance to wear of nickel-titanium endodontic instruments that have undergone a process of ionic implantation. ProFile .04 taper #25 instruments were subjected to ionic implantation with bands of nitrogen ions of 250 KeV, currents in the order of 10 microA/cm2, and doses of 2 x 10(17) ions/ cm2. The(More)
The present study was designed to compare the nature of modified surface layers obtained by two different procedures on endodontic files made of NiTi alloy: the procedures were arc evaporation physical vapor deposition and thermal metal organic chemical vapor deposition (MOCVD). Experimental samples were GT Rotary Instruments. The first method was based on(More)
This study evaluated the pitting corrosion resistance of nickel-titanium (NiTi) rotary instruments with different surface treatments in 17% ethylenediaminetetraacetic acid (EDTA) and NaCl solutions. Electropolished RaCe instruments were allocated to group A, non-electropolished RaCe instruments to group B, and physical vapor deposition (PVD)-coated Alpha(More)
Used rotary nickel-titanium instruments require frequent replacement. This laboratory study evaluated defects of GT Rotary instruments before and after usage. The instruments were fixed into custom-made holders and photographed in an SEM at x 260 to x 12,000 magnification at preset points. Instrument sizes 20 with 1.0, 0.8, and 0.6 taper and instrument(More)
OBJECTIVE Nickel-titanium instruments that offer greater flexibility than instruments made of other metallic materials have been developed. This study evaluated the behavior in vitro of nickel-titanium rotary instruments under repeated sterilization cycles. STUDY DESIGN To investigate changes in cutting ability and superficial alterations, 36 ProFile(More)
This study was designed to obtain nitrogen-rich layers on the surfaces of endodontic files made of nickel-titanium (NiTi) alloy by chemical vapor deposition. Experimental samples (GT rotary instruments) were deposited by using two different methods. The first one was based on the reaction of wet NH3 with NiTi under high temperatures (300 degrees C). The(More)
AIM To assess the failure mechanism of rotary NiTi instruments by chemical, structural and morphological analyses to provide a rational explanation of the effects of surface and bulk treatments on their resistance to fatigue fracture. METHODOLOGY Thermal treatment (350-500 °C) was performed on electropolished (EP) and non-electropolished (Non-EP) NiTi(More)