Shaping ability of four nickel-titanium rotary instruments in simulated S-shaped canals.

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 and post hoc Student-Newman-Keuls test were used for statistical analysis.

Chemical analysis of nickel-titanium rotary instruments with and without electropolishing after cleaning procedures with sodium hypochlorite.

The aim of this study was to chemically analyze rotary nickel-titanium instruments with and without electropolishing after cleaning procedures with NaOCl. To evaluate the effect of 5.25% NaOCl on electropolished RaCe instruments, a total of 18 instruments were tested.

Pitting corrosion resistance of nickel-titanium rotary instruments with different surface treatments in seventeen percent ethylenediaminetetraacetic Acid and sodium chloride solutions.

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 files to group C (10 instruments per group). Electrochemical measurements were carried out by using a potentiostat for galvanic current measurements.

Cyclic fatigue of different nickel-titanium endodontic rotary instruments.

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 from different sources: ProFile, RaCe, K3, Hero, and Mtwo. To compare the effect of electro-polishing procedures on fatigue resistance, a group of RaCe instruments (which are normally electro-polished) without surface treatment was used.

Proliferative activity in periapical lesions.

The identification of proliferative activity in periapical lesions may be useful in discovering the biological behaviour of different cell types. Proliferant cell nuclear antigen (PCNA), Ki67, CD3 and p53 have been used for the evaluation of the proliferative ability of many lesions. In this study, 16 periapical granulomas and 8 radicular cysts were analysed.

Fabrication of hard coatings on NiTi instruments.

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 the physical deposition of elemental titanium in the presence of nitrogen.

Depositions of nitrogen on NiTi instruments.

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).