Objective: To assess the mechanical effects of nickel-titanium orthodontic archwire flaming and their distribution along the wire. Methodology: Two sizes of pre-formed austenitic nickel-titanium archwires were tested (n=10). The terminal 5mm of each wire was heated for five seconds using a butane lighter. Micro-hardness testing was used to determine the heat-affected zone for all wires. Cantile...

background: the advantages of coated orthodontic wires such as esthetic and their effectson reduced friction, corrosion and allergic reaction and the signifi cant consequences of plaque accumulation on oral health encouraged us to assess bacterial colonization on these wires. materials and methods: a total of 18 (9 upper and 9 lower) epoxy resin coated 16 × 22 nickeltitanium wires (spectra, gac...

OBJECTIVE The aim of this study was to compare the cyclic fatigue resistance of two nickel-titanium (NiTi) endodontic instruments from ProTaper and GT series X files. STUDY DESIGN Cyclic fatigue test was realized with instruments from ProTaper: F1 and F3 (Denstply Maillefer, Ballaigues, Switzerland) and GT-X: 20.06 and 30.08 (Dentsply Tulsa Dental, Tulsa, Oklahoma, United States of America). ...

The aim of this study was to examine the lifespan or number of cycles to failure of tapered rotary nickel-titanium (Ni-Ti) endodontic instruments. Simulated root canals with different curvatures were used to determine a relation between canal curvature and instrument lifespan. Using a novel mathematical model for the deformation of pseudoelastic Ni-Ti alloy, it was shown that maximum stress nee...

This is part of a larger study designed to investigate the action of particulate metals of orthopaedic interest on tissues. Damaging effects were determined by cytological examination and the assay of two enzymes. Lactic dehydrogenase (LDH) if released into the supernatant indicates a damaged cell membrane; decreased intracellular levels of glucose-6-phosphate dehydrogenase (G6PD) indicates a l...

Using the recently developed SIMS-SPM prototype, secondary ion mass spectrometry (SIMS) data was combined with topographical data from the scanning probe microscopy (SPM) module for five test structures in order to obtain accurate chemical 3D maps: a polystyrene/polyvinylpyrrolidone (PS/PVP) polymer blend, a nickel-based super-alloy, a titanium carbonitride-based cermet, a reticle test structur...

Japanese nickel titanium (NiTi) alloy wire possesses excellent spring-back properties, shape memory and super-elasticity. In order to adapt this wire to clinical use, it is necessary to bend as well as to control its super-elastic force, and so a direct electric resistance heat treatment (DERHT) method was developed. An electric current is passed directly through the wire, thus generating enoug...

INTRODUCTION The Memokath® ureteric stent is a thermo-expandable titanium-nickel alloy.(1) Its use is not recommended in stone formers and patients with functional stenosis.(2) Unlike conventional plastic ureteric stents, it is a semi-permanent prosthesis. However, should removal be required simply flushing the stent with cold water returns it to a soft and pliable form. As these stents do not ...

Aims: To measure the microhardness of root canal dentin using two types of irrigating solutions( 0.2% Chlorhexidine and 5.25% Sodium Hypochlorite) with and with out use of different types of root canal files (Stainless Steel-K files, Nickel-Titanium K-files or rotary Nickel-Titanium files). Materials & methods: The teeth divided in to four groups according to the type of irrigating solutions th...