PDF A simple and selective complexometric method for the determination of thallium in presence of other The released EDTA is titrated with standard zinc sulphate solution as before. Sorry, there is no online preview for this file type. Statistical Evaluation of Acid-Base Indicators. The HI finds a titration endpoint using a polarized electrode and an advanced detection.. In a complexometric titration, metal ions are titrated using a. After removing the samples, stereomicroscopy images were captured, coating loss was measured and its percentage was calculated.
|Genre:||Health and Food|
|Published (Last):||2 June 2013|
|PDF File Size:||10.75 Mb|
|ePub File Size:||20.4 Mb|
|Price:||Free* [*Free Regsitration Required]|
Corrosion resistance and mechanical properties of titanium nitride plating on orthodontic wires. Titanium nitride Ti N coating by ion plating has properties such as high hardness, wear resistance, corrosion resistance, and surface lubricity, therefore Ti N coating is often used in various dental appliances and materials.
In this study, we evaluated the corrosion behaviors and mechanical properties of Ti N coated stainless steel SS and nickel titanium Ni- Ti orthodontic wires prepared by ion plating. Ti N coating by ion plating improves the corrosion resistance of orthodontic wires.
The corrosion pitting of the Ti N coated wire surface become small. The tensile strength and stiffness of SS wire were increased after Ti N coating.
In contrast, its elastic force, which is a property for Ni- Ti wire , was decreased. In addition, Ti N coating provided small friction forces. The low level of friction may increase tooth movement efficiently. Therefore, Ti N coated SS wire could be useful for orthodontics treatment. Phase transformation changes in thermocycled nickel- titanium orthodontic wires.
In the oral environment, orthodontic wires will be subject to thermal fluctuations. The purpose of this study was to investigate the effect of thermocycling on nickel- titanium Ni Ti wire phase transformations. A control group consisted of five randomly selected non-thermocycled segments. Nitinol HA and Sentalloy did not demonstrate qualitative or quantitative phase transformation behavior differences.
Significant differences were observed in some of the copper Ni Ti transformation temperatures, as well as the heating enthalpy with the 27 degrees C copper Ni Ti wires p Ti , and an austenite to martensite peak shoulder developed during cooling in the 27 degrees C copper Ni Ti.
Repeated temperature fluctuations may contribute to qualitative and quantitative phase transformation changes in some Ni Ti wires. Copyright Academy of Dental Materials. All rights reserved. Effect of fluoride prophylactic agents on the mechanical properties of nickel- titanium -based orthodontic wires.
Titanium -based alloys have high corrosion resistance because they form a thin, stable oxide layer. Nevertheless, fluoride prophylactic agents can cause corrosion and associated discoloration of titanium -based orthodontic wires. The purpose of this investigation was to study the effects of fluoride prophylactic agents on the mechanical properties of nickel- titanium Ni- Ti and copper-nickel- titanium Cu-Ni- Ti orthodontic archwires.
Preformed rectangular Ni- Ti and Cu-Ni- Ti wires were immersed in either an acidulated fluoride agent, a neutral fluoride agent, or distilled water control for 1. Scanning electron microscopy was also used to characterize the effects of the fluoride treatment on the wire topography. Corrosive changes in surface topography were observed for both wires , with Cu-Ni- Ti appearing to be more severely affected.
The results suggest that using topical fluoride agents with Ni- Ti wire could decrease the functional unloading mechanical properties of the wire and contribute to prolonged orthodontic treatment.
Joining characteristics of titanium -based orthodontic wires connected by laser and electrical welding methods. This study investigated the possibility of electrical and laser welding to connect titanium -based alloy beta- titanium and nickel- titanium wires and stainless-steel or cobalt-chromium alloy wires for fabrication of combination arch- wires.
Four kinds of straight orthodontic rectangular wires 0. Homogeneous and heterogeneous end-to-end joints 15 mm long each were made by electrical welding and laser welding. Non-welded wires 30 mm long were also used as a control.
Nickel- titanium shape memory alloy Ni Ti is a new suture material that is easy to handle, is strong, and biocompatible. The purpose of this study was to evaluate the material properties and biomechanical behaviour of microm and microm Ni Ti wires in flexor tendon repair. Braided polyester Ethibond was used as control.
Fifty fresh-frozen porcine flexor tendons were repaired using the Pennington modification of the Kessler repair or a double Kessler technique. Ni Ti wires were stiffer and reached higher tensile strength compared to braided polyester suture. Repairs with microm Ni Ti wire had a higher yield force, ultimate force and better resistance to gapping than braided polyester repairs.
Repairs made with microm Ni Ti wire achieved higher stiffness and ultimate force than repairs made with microm Ni Ti wire. Dynamic mechanical properties of straight titanium alloy arch wires. Eight straight- wire materials were studied: an orthodontic titanium -molybdenum Ti -Mo product, TMA; three orthodontic nickel- titanium Ni- Ti products, Nitinol, Titanal, and Orthonol; three prototype alloys, a martensitic, an austenitic, and a biphasic alloy; and a hybrid shape-memory-effect product, Biometal.
Each wire was prepared with a length-to-cross-sectional area of at least cm From the data base, plots of the log storage modulus, log tan delta, and percent change in length vs. Results showed that the dynamic mechanical properties of the alloys within this TI system are quite different.
The three cold-worked alloys--Nitinol, Titanal, and Orthonol--appeared to be similar, having a modulus of 5. Among the Ni- Ti wires tested, several different types of alloys were represented by this intermetallic material. Material and biofilm load of K wires in toe surgery: titanium versus stainless steel. Recurrence rates for toe deformity correction are high and primarily are attributable to scar contractures.
These contractures may result from subclinical infection. We hypothesized that 1 recurrence of toe deformities and residual pain are related to low-grade infections from biofilm formation on percutaneous K wires , 2 biofilm formation is lower on titanium Ti K wires compared with stainless steel SS K wires , and 3 clinical outcome is superior with the use of Ti K wires compared with SS K wires. K wires were removed after 6 weeks. The presence of biofilm-related infections was analyzed by sonication.
Increased bacterial load was associated with pain and swelling but not recurrence of the deformity. Ti K wires showed superior clinical outcomes to SS K wires. This appears to be attributable to reduced infection rates. Although additional study is needed, we currently recommend the use of Ti K wires for the transfixation of toe deformities.
Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. Metallurgical characterization of a new nickel- titanium wire for rotary endodontic instruments.
A novel thermomechanical processing procedure has been developed that yields a superelastic SE nickel- titanium Ni Ti wire M- Wire that laboratory testing shows has improved mechanical properties compared with conventional SE austenitic Ni Ti wires used for manufacture of rotary instruments.
The objective of this study was to determine the origin of the improved mechanical properties. Specimens from 2 batches of M- Wire prepared under different processing conditions and from 1 batch of standard-processed SE wire for rotary instruments were examined by scanning transmission electron microscopy, temperature-modulated differential scanning calorimetry, micro-x-ray diffraction, and scanning electron microscopy with x-ray energy-dispersive spectrometric analyses.
The processing for M- Wire yields a microstructure containing martensite, that the proportions of Ni Ti phases depend on processing conditions, and that the microstructure exhibits pronounced evidence of alloy strengthening.
The presence of Ti 2 Ni precipitates in both microstructures indicates that M- Wire and the conventional SE wire for rotary instruments are titanium -rich. This study reports on the long-term fracture resistance of orthodontic nickel titanium wires , a material property that has not been investigated thoroughly, yet. A computer-controlled apparatus was designed to perform long-term bending tests. The investigated material comprised 9 nickel titanium wires dimensions 0.
Compared with the steel wire , the nickel titanium wires exhibited 2- to 5-fold higher yield forces in bending. At a specified deflection angle, the generated bending forces of the nickel titanium wires reached one half to one fourth of the values of steel.
After 10 5 loadings, 0. Steel and TMA wires could be loaded with forces of up to 4. The 0. Material degradation lead to a severe deformation of the hysteresis loop and to plastic deformation.
Work-hardened martensitic Ni Ti wires did not show these effects to this extent. The aim of this study was to see the effect of topical fluoride on surface texture on nickel- titanium and copper-nickel- titanium orthodontic archwires.
The acidulated fluoride agents appeared to cause greater corrosive effects as compared to the neutral fluoride agents.
The result suggest that using topical fluoride agents leads to corrosion of surface topography indirectly affecting the mechanical properties of the wire that will lead to prolonged orthodontic treatment. The use of topical fluoride agents has to be limited in patients with prolonged orthodontic treatment as it causes the corrosion of the Ni Ti and CuNi Ti wires. Nickel- titanium wire in circumferential suture of a flexor tendon repair: a comparison to polypropylene.
Nickel- titanium Ni Ti has been proposed as an alternative material for flexor tendon core suture. To our knowledge, its suitability as a circumferential suture of flexor tendon repair has not been investigated before. The purpose of this ex vivo study was to investigate the biomechanical properties of Ni Ti circumferential repairs and to compare them with commonly used polypropylene.
Forty porcine flexor tendons were cut and repaired by simple running or interlocking mattress technique using microm Ni Ti wire or polypropylene. The Ni Ti circumferential repairs showed superior stiffness, gap resistance, and load to failure when compared to polypropylene repairs with both techniques.
Nickel- titanium wire seems to be a potential material for circumferential repair of flexor tendons. Copyright American Society for Surgery of the Hand. Published by Elsevier Inc. An evaluation of two types of nickel- titanium wires in terms of micromorphology and nickel ions' release following oral environment exposure.
This study aimed to compare superelastic and heat-activated nickel- titanium orthodontic wires ' surface morphology and potential release of nickel ions following exposure to oral environment conditions. Heat-activated nickel- titanium Ni Ti wires were rougher than superelastic wires , and both types of wires released almost the same amount of Ni ions. After clinical exposure, more surface roughness was recorded for superelastic Ni Ti wires and heat-activated Ni Ti wires.
However, retrieved superelastic Ni Ti wires released less Ni ions in artificial saliva after clinical exposure, and the same result was recorded regarding heat-activated wires. Both types of Ni Ti wires were obviously affected by oral environment conditions; their surface roughness significantly increased while the amount of the released Ni ions significantly declined. Corrosion behavior of ion implanted nickel- titanium orthodontic wire in fluoride mouth rinse solutions. This study investigated the corrosion properties of ion implanted nickel- titanium wire Neo Sentalloy Ionguard in artificial saliva and fluoride mouth rinse solutions Butler F Mouthrinse, Ora-Bliss.
Non ion implanted nickel- titanium wire Neo Sentalloy was used as control. The anodic corrosion behavior was examined by potentiodynamic polarization measurement. The surfaces of the specimens were examined with SEM. The elemental depth profiles were characterized by XPS.
ESTIMATION OF ZINC BY COMPLEXOMETRIC TITRATION FILETYPE PDF