Alloys In Artificial Saliva Research Articles

Corrosion Resistance of an SS 316L Alloy in Artificial Saliva in Presence of a Sparkle Fresh Toothpaste

Corrosion Resistance of an SS 316L Alloy in Artificial Saliva in Presence of a Sparkle Fresh Toothpaste

Effect of recasting on element release from base metal dental casting alloys in artificial saliva and saline solution.

Aim:The aim of this study was to quantitatively estimate the concentration of ion release from recasted base metal alloys in various pH conditions using atomic absorption spectroscopy (AAS).Materials and Methods:Specimens of commercially available dental casting alloys (cobalt [Co]-chromium [Cr] and nickel [Ni]- chromium [Cr]) were prepared using lost-wax casting techniques and were stored in the test solution for 1 week and 4 weeks, and ions released during chemical corrosion were detected using AAS.Results:An increase in the quantity of ion release was observed with recasting. These changes were higher after twice recasting in Ni-Cr alloy.

Evaluation of Corrosive Behavior of Four Nickel–chromium Alloys in Artificial Saliva by Cyclic Polarization Test:An in vitro Study

Evaluation of Corrosive Behavior of Four Nickel–chromium Alloys in Artificial Saliva by Cyclic Polarization Test:An in vitro Study

Corrosion resistance of Ni-Ti alloy, SS18/8 alloy and thermoactive alloy in artificial saliva in the absence and presence of tea

Corrosion resistance of Ni-Ti alloy, SS18/8 alloy and thermoactive alloy in artificial saliva in the absence and presence of tea

Influence of some tablets on corrosion resistance of orthodontic wire made of SS 316L alloy in artificial saliva

Influence of some tablets on corrosion resistance of orthodontic wire made of SS 316L alloy in artificial saliva

Tribocorrosion behavior of hot pressed CoCrMo alloys in artificial saliva

The aim of this work was to investigate the influence of the processing conditions on the tribocorrosion behavior of hot pressed CoCrMo biomedical alloys. Several samples were processed as a function of different processing temperatures (900, 1000 and 1100°C) and times (10, 30 and 60min). Tribocorrosion tests were carried out in artificial saliva at 37°C, under 1N normal load, 1Hz frequency and 3mm stroke length. Open circuit potential was measured. The worn surfaces were inspected by means of SEM/EDS. Results revealed a decrease of wear rate with increasing hot pressing time. The samples hot pressed at 1000°C revealed the lowest wear rate. These findings showed that the processing conditions play a relevant role on tribocorrosion behavior of CoCrMo.

Electrochemical impedance investigation of Ni-free Co-Cr-Mo and Co-Cr-Mo-Ni dental casting alloy for partial removable dental prosthesis frameworks

Statement of problemThe pH level of the oral environment influences corrosion in dental materials. Corrosion behaviors of Co-Cr-Mo and Co-Cr-Mo-Ni alloys in different pH environments remain undetermined. PurposeThe purpose of this in vitro study was to evaluate the surface properties and corrosion behaviors of Co-Cr-Mo and Co-Cr-Mo-Ni dental casting alloys in artificial saliva at pH values of 5.0 and 2.5. Material and methodsFifty specimens were divided into 2 groups according to the alloy composition. The surface compositions, hardness values, and microstructures of the alloys were measured before immersion in artificial saliva. The corrosion behaviors of the specimens in artificial saliva at pH values of 5.0 and 2.5 were studied using electrochemical impedance spectroscopy (EIS). The microstructures were examined again after a 7-day immersion test. Data were analyzed by a 1-way analysis of variance (ANOVA) test (α=.05). ResultsAs expected, the relative levels of Co and Cr of the surface composition were higher in the Co-Cr-Mo alloy. The Co-Cr-Mo alloy had statistically higher surface hardness than the Co-Cr-Mo-Ni alloy (P<.05). In the pH 2.5 environment, both of the alloys showed decreased corrosion resistance (P<.05). The microstructure of the Co-Cr-Mo-Ni alloy corroded more than that of the Co-Cr-Mo alloy in the pH 2.5 environment. The oxide-layer corrosion resistance of the Co-Cr-Mo alloy was better than that of the Co-Cr-Mo-Ni alloy in Fusayama artificial saliva solutions at pH values of both 5.0 and 2.5 (P<.05). ConclusionsThe corrosion resistance of the Co-Cr-Mo alloy was better in the oral environment, especially at a low pH value.

Electrochemical comparison and biological performance of a new CoCrNbMoZr alloy with commercial CoCrMo alloy

A new CoCrNbMoZr alloy, with Nb and Zr content is characterized from the point of view of surface features, corrosion resistance and biological performance in order to be proposed as dental restorative material. Its properties are discussed in comparison with commercial Heraenium CE alloy based on Co, Cr and Mo as well. The microstructure of both alloys was revealed by scanning electron microscopy (SEM). The composition and thickness of the alloy native passive films were identified by X-ray photoelectron spectroscopy (XPS). The surface characteristics were analyzed by atomic force microscopy (AFM) and contact angle techniques. The quantity of ions released from alloys in artificial saliva was evaluated with inductively coupled plasma-mass spectroscopy (ICP-MS) measurements. The electrochemical stability was studied in artificial Carter–Brugirard saliva, performing open circuit potentials, polarization resistances and corrosion currents and rates. The biological performance of the new alloy was tested in vitro in terms of human adipose stem cells (hASCs) morphology, viability and proliferation status. The new alloy is very resistant to the attack of the aggressive ions from the artificial saliva. The surface properties, the roughness and wettabiliy sustain the cell behavior. The comparison of the new alloy behavior with that of existing commercial CoCrMo alloy showed the superior properties of the new metallic biomaterial.

Effect of Fluorine Ion on the Corrosion of Ti-6Al-4V Alloy in Artificial Saliva

Effect of Fluorine Ion on the Corrosion of Ti-6Al-4V Alloy in Artificial Saliva

Corrosion Behavior of TiSiN Coatings Deposited on Ni-Cr Alloy in Artificial Saliva with and without Fluoride

TiSiN thin films were deposited on NiCr dental alloy in order to enhance the corrosion resistance in artificial saliva with and without fluoride content. The TiSiN films were prepared using reactive cathodic arc method at two different substrate bias voltages (-50 V and-200 V). For the corrosion evaluation, artificial saliva with pH=5.2 was chosen, because this is a critical value for mineral dissolution of dental tissue which can affect the dental alloys. A content of 0.1 % NaF was added to the artificial saliva to simulate the effect of fluoride based hygiene products. The TiSiN coated NiCr alloys exhibited a higher corrosion resistance than the NiCr substrate, irrespective of the testing environment. The best corrosion resistance was found for the TiSiN deposited at-200 V.

Tribocorrosion Mechanisms of Ti6Al4V in Artificial Saliva by Zero-Resistance Ammetry (ZRA) Technique

Degradation mechanisms of biomedical alloys involve two different phenomena, corrosion and wear, which simultaneously act and may cause the failure of implants and prosthesis. In this work, tribocorrosion of Ti6Al4V biomedical alloy in artificial saliva is studied at open circuit potential (OCP) by a new electrochemical technique that allows measuring the galvanic potential and current between the wear track (anode) and the passive material (cathode) through zero-resistance ammetry. The experimental set-up was conceived for physically separating the depassivated area from the passive material, thus allowing to quantify the mechanically activated corrosion at OCP. Two different counterparts, SiC and Al2O3, were used against the Ti6Al4V alloy in order to analyse the influence of the initial contact pressure on the tribocorrosion mechanisms. A galvanic model based on the cathodic reaction kinetics can describe the current and the potential evolution with time during sliding. It has been observed that at the highest initial contact pressures, wear follows the Archard law, while at lower contact pressures, third body appeared and wear can not be described by the Archard law. Quantification of the evolution of the depassivated wear track with time was obtained and the deviation from the Archard predictions was analysed.

Corrosion Performance of Fe-Cr-Ni Alloys in Artificial Saliva and Mouthwash Solution.

Several austenitic stainless steels suitable for high temperature applications because of their high corrosion resistance and excellent mechanical properties were investigated as biomaterials for dental use. The steels were evaluated by electrochemical techniques such as potentiodynamic polarization curves, cyclic polarization curves, measurements of open circuit potential, and linear polarization resistance. The performance of steels was evaluated in two types of environments: artificial saliva and mouthwash solution at 37°C for 48 hours. In order to compare the behavior of steels, titanium a material commonly used in dental applications was also tested in the same conditions. Results show that tested steels have characteristics that may make them attractive as biomaterials for dental applications. Contents of Cr, Ni, and other minor alloying elements (Mo, Ti, and Nb) determine the performance of stainless steels. In artificial saliva steels show a corrosion rate of the same order of magnitude as titanium and in mouthwash have greater corrosion resistance than titanium.

Study of Corrosion Resistance of Co-Cr-Mo Surgical Implants Alloy in Artificial Saliva

Study of Corrosion Resistance of Co-Cr-Mo Surgical Implants Alloy in Artificial Saliva

Determination of corrosion rate of orthodontic wires based on nickel-titanium alloy in artificial saliva

The goal of this study was to determine corrosion behavior of three orthodontic wires based on nickel-titanium alloy (NiTi) in artificial saliva at temperature of 37 °C as function of immersion time. Following orthodontic wires were used: uncoated (NiTi), rhodium coated (Rh NiTi) and nitrified (N NiTi) orthodontic wires. Corrosion of investigated orthodontic wires were monitored by measuring of Ni2+ and Ti4+ ions released in artificial saliva by inductively coupled plasma- optical emission spectroscopy (ICP-OES) after 3, 7, 14, 21 and 28 days of immersion. Obtained results indicate that corrosion reaction of the NiTi wires in artificial saliva follows the parabolic rate law. According to the obtained values of parabolic corrosion rate constants, corrosion susceptibility of orthodontic wires decreases in the following order: Rh NiTi wire (Kp = 2.48 μg2/cm4 h) > NiTi wire (Kp = 1.6 × 10–3 μg2/cm4 h) > N NiTi wire (Kp = 6.0 × 10–4 μg2/cm4 h). These results indicate that in comparison with uncoated NiTi wire, rhodium coating significantly increases corrosion susceptibility, while nitrification effectively suppresses the release of Ni2+ and Ti4+ ions.

Dual motion fretting wear behaviors of titanium and its alloy in artificial saliva

A dual motion combined by radial and tangential fretting was achieved on a modified hydraulic fretting wear test rig. The dual motion fretting tests of medical pure titanium (TA2) and Ti6Al7Nb alloy in artificial saliva were carried out under varied contact inclined angles (45° and 60°), and the maximum imposed load varied from 200 to 400 N at a constant loading speed of 6 mm/min. The effects of the cyclic vertical force and the inclined angle were investigated in detail. Dynamic analysis in combination with microscopic examinations shows that the wear scar and plastic deformation accumulation present a strong asymmetry. The Ti6Al7Nb has better wear resistance than TA2 in artificial saliva at the same test parameters, and with the increase of inclined angle and decrease of imposed load, the wear reduces accordingly. The wear mechanisms of pure titanium TA2 and Ti6Al7Nb alloy under the condition of dual motion fretting in artificial saliva are abrasive wear, oxidative wear and delamination.

Metallic ion release from biocompatible cobalt-based alloy

Metallic biomaterials, which are mainly used for the damaged hard tissue replacements, are materials with high strength, excellent toughness and good wear resistance. The disadvantages of metals as implant materials are their susceptibility to corrosion, the elastic modulus mismatch between metals and human hard tissues, relatively high density and metallic ion release which can cause serious health problems. The aim of this study was to examine metallic ion release from Co-Cr-Mo alloy in artificial saliva. In that purpose, alloy samples were immersed into artificial saliva with different pH values (4.0, 5.5 and 7.5). After a certain immersion period (1, 3 and 6 weeks) the concentrations of released ions were determined using Inductively Coupled Plasma - Mass Spectrophotometer (ICP-MS). The research findings were used in order to define the dependence between the concentration of released metallic ions, artificial saliva pH values and immersion time. The determined released metallic ions concentrations were compared with literature data in order to describe and better understand the phenomenon of metallic ion release from the biocompatible cobalt-based alloy.

Effects of environment on the release of Ni, Cr, Fe, and Co from new and recast Ni-Cr alloy

The addition of previously cast alloy to new alloy for economic reasons may increase the release of elements. The purpose of this study was to analyze the effects of the immersion period, immersion media, and addition of previously cast alloy to new alloy on the release of elements. Disk-shaped specimens were prepared from a Ni-Cr alloy (Ni: 61 wt%, Cr: 26 wt%, Mo: 11 wt%, Si: 1.5 wt%, Fe, Ce, Al, and Co <1 wt%) (Remanium CS; Dentaurum) with new alloy (group N) and 50% new/50% recast alloy (group R). After the immersion of the specimens in both NaCl (pH 4) and artificial saliva (pH 6.7) for 3, 7, 14, 30, and 60 days, the release of ions was determined by using atomic absorption spectrometry. Data were analyzed with a 3-way ANOVA (α=.001). The release of Ni was significantly affected by the immersion period, of Ni and Cr by the alloy and media (P<.01), and of Fe by the alloy (P<.01). Ion release from the recast alloy in artificial saliva was 109.71 for Ni, 6.49 for Cr, 223.22 for Fe, and 29.90 μg/L for Co. The release of Co in NaCl was below the detection limit in both groups. The release of Ni in NaCl and artificial saliva increased with the length of the immersion period in both groups. The release of Cr and Fe was higher in artificial saliva than in NaCl in group R, regardless of the immersion period. The release of Co in NaCl was below the detection limit in both groups.

Are new TiNbZr alloys potential substitutes of the Ti6Al4V alloy for dental applications? An electrochemical corrosion study

The main aim of this work was to assess the electrochemical behavior of new Ti35Nb5Zr and Ti35Nb10Zr alloys in artificial saliva at 37 °C to verify if they are indicated to be used as biomaterials in dentistry as alternatives to Ti6Al4V alloys in terms of corrosion protection efficiency of the material. Electrochemical impedance spectroscopy (EIS) experiments were carried out for different periods of time (0.5–216 h) in a three-electrode cell, where the working electrode (Ti alloys) was exposed to artificial saliva at 37 °C. The near-surface region of the alloys was investigated using x-ray photoelectron spectroscopy (XPS). All alloys exhibited an increase in corrosion potential with the immersion time, indicating the growth and stabilization of the passive film. Ti35Nb5Zr and Ti6Al4V alloys had their EIS results interpreted by a double-layer circuit, while the Ti35Nb10Zr alloy was modeled by a one-layer circuit. In general, the new TiNbZr alloys showed similar behavior to that observed for the Ti6Al4V. XPS results suggest, in the case of the TiNbZr alloys, the presence of a thicker passive layer containing a lower fraction of TiO2 phase than that of Ti6Al4V. After long-term immersion, all alloys develop a calcium phosphate phase on the surface. The new TiNbZr alloys appear as potential candidates to be used as a substitute to Ti6Al4V in the manufacturing of dental implant-abutment sets.

Corrosion Behavior of AZ91D Magnesium Alloy in Three Different Physiological Environments

Magnesium alloys have been considered as promising biomedical materials and were studied in different physiological environments. In this work, corrosion behavior of AZ91D magnesium alloy in artificial saliva, simulated body fluid (SBF), and 3.5 wt.% NaCl solution was investigated using electrochemical techniques and a short-term immersion test. In contrast with other physiological environments, the amount of aggressive ions in artificial saliva is small. In addition, a protective film is formed on the surface of samples in artificial saliva. Experimental results suggest that corrosion resistance of AZ91D magnesium alloy in artificial saliva is better than that in c-SBF and 3.5 wt.% NaCl solution.

Tribocorrosion mechanisms of Ti6Al4V biomedical alloys in artificial saliva with different pHs

Titanium and its alloys has been widely used for the design of dental implants because of its biocompatibility, mechanical properties and corrosion resistance. The powder-metallurgy process is a promising alternative to the casting fabrication process of titanium alloys for bone implants design as the porous structure mimics the natural bone structures, allowing the bone to grow into the pores which results in a better fixation of the artificial implant. However, under in vivo conditions the implants are subjected to tribocorrosion phenomenon, which consists in the degradation mechanisms due to the combined effect of wear and corrosion. The aim of this study is to evaluate the tribocorrosion behaviour of cast and sintered Ti6Al4V biomedical alloy for dental applications using the cast material as reference. Titanium samples were tested in artificial human saliva solution with three different pHs (3, 6, 9) and in an acidic saliva with 1000 ppm fluorides (AS-3-1000F−) by different electrochemical techniques (potentiodynamic curves, potentiostatic tests and tribo-electrochemical tests). Cast and sintered titanium alloys exhibit the same tribocorrosion mechanisms in AS independently of the pH which consists in plastic deformation with passive dissolution, but the addition of fluorides to the acidified solution changes the degradation mechanism towards active dissolution of the titanium alloys.