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Brazilian Dental Journal 2012The aim of this study was to determine the effect of the oral environment on the corrosion of dental alloys with different compositions, using electrochemical methods....
The aim of this study was to determine the effect of the oral environment on the corrosion of dental alloys with different compositions, using electrochemical methods. The corrosion rates were obtained from the current-potential curves and electrochemical impedance spectroscopy (EIS). The effect of artificial saliva on the corrosion of dental alloys was dependent on alloy composition. Dissolution of the ions occurred in all tested dental alloys and the results were strongly dependent on the general alloy composition. Regarding the alloys containing nickel, the Ni-Cr and Ni-Cr-Ti alloys released 0.62 mg/L of Ni on average, while the Co-Cr dental alloy released ions between 0.01 and 0.03 mg/L of Co and Cr, respectively.The open-circuit potential stabilized at a higher level with lower deviation (standard deviation: Ni-Cr-6Ti = 32 mV/SCE and Co-Cr = 54 mV/SCE). The potenciodynamic curves of the dental alloys showed that the Ni-based dental alloy with >70 wt% of Ni had a similar curve and the Co-Cr dental alloy showed a low current density and hence a high resistance to corrosion compared with the Ni-based dental alloys. Some changes in microstructure were observed and this fact influenced the corrosion behavior for the alloys. The lower corrosion resistance also led to greater release of nickel ions to the medium. The quantity of Co ions released from the Co-Cr-Mo alloy was relatively small in the solutions. In addition, the quantity of Cr ions released into the artificial saliva from the Co-Cr alloy was lower than Cr release from the Ni-based dental alloys.
Topics: Corrosion; Dental Alloys; Dielectric Spectroscopy; Electrochemistry; Ions; Potentiometry; Saliva, Artificial; Surface Properties
PubMed: 22666772
DOI: 10.1590/s0103-64402012000200009 -
BioMed Research International 2021This paper reports the corrosion behavior of uncoated commercially pure titanium and Ti-6Al-4V samples and these coated with hydroxyapatite, partial stabilized zirconia...
BACKGROUND
This paper reports the corrosion behavior of uncoated commercially pure titanium and Ti-6Al-4V samples and these coated with hydroxyapatite, partial stabilized zirconia (PSZ), and the mixture of partial stabilized zirconia and hydroxyl-apatite by measuring passivation current density and see if there are any differences between them using electrochemical polarization tests in 37°C Hank's solution.
MATERIALS AND METHODS
The electrophoretic deposition method (EPD) was elected to keep the coating materials which are HA, PSZ, and the mixture of 50% HA and 50% PSZ on Cp Ti and Ti-6Al-4V alloy samples. The electrochemical corrosion test was achieved by exposing the coated and uncoated samples to Hank's solution which prepared in the laboratory and measuring the polarization potential, passivation current density, and the open circuit potential for all samples.
RESULTS
The results indicated that the passivation current density for all Cp Ti and Ti-6Al-4V alloy groups that coated with HA, PSZ, and with mixture of 50/50 HA and PSZ was less than uncoated groups. There are no significant differences between all Cp Ti groups when compared with all Ti-6Al-4 V alloy groups. The open circuit potential (OCP) for both Cp Ti and Ti -6Al -4V samples was in the following sequence PSZ > HA > mixture of HA and PSZ > uncoated.
CONCLUSIONS
Coating significantly decreased the passivation current density of Cp Ti and Ti-6Al-4V alloy.
Topics: Alloys; Ceramics; Coated Materials, Biocompatible; Corrosion; Dental Alloys; Dental Implants; Durapatite; Electrochemistry; Electrophoresis; Humans; Materials Testing; Reproducibility of Results; Surface Properties; Titanium; X-Ray Diffraction; Zirconium
PubMed: 34222489
DOI: 10.1155/2021/9934073 -
Dental Materials Journal Jul 2019The goal of this study was to investigate the chemical alteration of a dental alloy surface by alumina air-abrasion and its effect on bonding to resin cement. Alumina...
The goal of this study was to investigate the chemical alteration of a dental alloy surface by alumina air-abrasion and its effect on bonding to resin cement. Alumina air-abrasion was carried out on an Ag-Pd-Cu-Au alloy. The surface morphology and chemical state of the abraded alloy were characterized. The effect of the air-abrasion on the shear bond strength between the alloy and a methyl methacrylate/tri-n-butyl borane (MMA/TBB) resin cement with some primers was evaluated. The surface characterization revealed that the alumina air-abrasion mechanically roughened and chemically altered the surface. The chemical alterations had two effects: (1) abraded alumina particles remained on the alloy surface and (2) copper ions were oxidized in the alloy surface. As the result, the shear bond strength test indicated that 10-methacryloyloxydecyl dihydrogen phosphate (MDP) contained primer worked with the abraded alloy surface, whereas it did not work with the non-abraded alloy surface.
Topics: Aluminum Oxide; Dental Alloys; Dental Bonding; Dental Stress Analysis; Materials Testing; Resin Cements; Shear Strength; Surface Properties
PubMed: 30971652
DOI: 10.4012/dmj.2018-276 -
Dental Materials Journal Apr 2022Ti-Zr alloys have been investigated as an alternative to commercially pure Ti (c.p.Ti). According to our previous studies on the mechanical properties of Ti-Zr alloys, a...
Ti-Zr alloys have been investigated as an alternative to commercially pure Ti (c.p.Ti). According to our previous studies on the mechanical properties of Ti-Zr alloys, a Zr proportion in the range of 30-50 mol% has competitive advantages over Ti-10Zr and c.p.Ti. The aim of this study is to evaluate the biological response to Ti-Zr alloys with different compositions and their surface characteristics. Alloy surfaces are modified by sandblasting and sulfuric acid etching. As a result, similar surface structures are observed for c.p.Ti, Ti-10Zr, and Ti-30Zr, whereas Ti-50Zr does not form a micro-rough structure by the same treatment process. No significant difference is found in the viability of cells on c.p.Ti, Ti-10Zr, and Ti-30Zr, whereas lower cell attachment levels are detected on Ti-50Zr. In summary, Ti-30Zr reliably forms a micro-rough structure, which provides one evidence for its application in a new dental implant material.
Topics: Alloys; Biocompatible Materials; Dental Alloys; Materials Testing; Surface Properties; Titanium; Zirconium
PubMed: 34866118
DOI: 10.4012/dmj.2021-210 -
Dental Materials Journal Sep 2000Ag-Pd-Au-Cu quaternary alloys consisting of 30-50% Ag, 20-40% Pd, 10-20% Cu and 20% Au (mother alloys) were prepared. Then 5% Sn or 5% Ga was added to the mother alloy...
Development of Ag-Pd-Au-Cu alloy for multiple dental applications. Part 1. Effects of Pd and Cu contents, and addition of Ga or Sn on physical properties and bond with ultra-low fusing ceramic.
Ag-Pd-Au-Cu quaternary alloys consisting of 30-50% Ag, 20-40% Pd, 10-20% Cu and 20% Au (mother alloys) were prepared. Then 5% Sn or 5% Ga was added to the mother alloy compositions, and another two alloy systems (Sn-added alloys and Ga-added alloys) were also prepared. The bond between the prepared alloys and an ultra-low fusing ceramic as well as their physical properties such as the solidus point, liquidus point and the coefficient of thermal expansion were evaluated. The solidus point and liquidus point of the prepared alloys ranged from 802 degrees C to 1142 degrees C and from 931 degrees C to 1223 degrees C, respectively. The coefficient of thermal expansion ranged from 14.6 to 17.1 x 10(-6)/degrees C for the Sn- and Ga-added alloys. In most cases, the Pd and Cu contents significantly influenced the solidus point, liquidus point and coefficient of thermal expansion. All Sn- and Ga-added alloys showed high area fractions of retained ceramic (92.1-100%), while the mother alloy showed relatively low area fractions (82.3%) with a high standard deviation (20.5%). Based on the evaluated properties, six Sn-added alloys and four Ga-added alloys among the prepared alloys were suitable for the application of the tested ultra-low fusing ceramic.
Topics: Analysis of Variance; Chemical Phenomena; Chemistry, Physical; Copper; Dental Casting Technique; Differential Thermal Analysis; Gallium; Gold Alloys; Hot Temperature; Lead; Materials Testing; Metal Ceramic Alloys; Metallurgy; Palladium; Silver; Statistics, Nonparametric; Tin
PubMed: 11218849
DOI: 10.4012/dmj.19.294 -
The Bulletin of Tokyo Dental College May 2000Dental alloy surface finishing procedures of may influence their electrochemical behavior, which is used to evaluate their corrosion resistance. We examined the... (Comparative Study)
Comparative Study
Dental alloy surface finishing procedures of may influence their electrochemical behavior, which is used to evaluate their corrosion resistance. We examined the polarization resistance and potentiodynamic polarization profile of the precious-metal alloys, Type 4 gold alloy and silver-palladium alloy, and the base-metal alloys, nickel-chromium alloy, cobalt-chromium alloy, and CP-titanium. Three types of finishing procedure were examined: mirror-finishing using 0.05 micron alumina particles, polishing using #600 abrasive paper and sandblasting. Dissolution of the alloy elements in 0.9% NaCl solution was also measured and compared with the electrochemical evaluation. The corrosion resistance of the dental alloys was found to relate to finishing as follows: The polarization resistance and potentiodynamic polarization behavior revealed that the corrosion resistance improved in the order of sandblasting, #600-abrasive-paper polishing, and mirror-finishing. While the corrosion potential, critical current density and passive current density varied depending on the type of finishing, the transpassive potential remained unchanged. The influence of finishing on the corrosion resistance of precious-metal alloys was less significant than on that of base-metal alloys. A mirror-finishing specimen was recommended for use in evaluation of the corrosion resistance of various dental alloys.
Topics: Alloys; Aluminum Oxide; Chromium Alloys; Corrosion; Dental Alloys; Dental Polishing; Electric Impedance; Electrochemistry; Gold Alloys; Humans; Materials Testing; Palladium; Paper; Potentiometry; Silicon Dioxide; Silver; Sodium Chloride; Solubility; Surface Properties; Titanium
PubMed: 11212579
DOI: 10.2209/tdcpublication.41.49 -
Dento Maxillo Facial Radiology 2013To investigate the potential influence of standard dental materials on dental MRI (dMRI) by estimating the magnetic susceptibility with the help of the MRI-based...
OBJECTIVES
To investigate the potential influence of standard dental materials on dental MRI (dMRI) by estimating the magnetic susceptibility with the help of the MRI-based geometric distortion method and to classify the materials from the standpoint of dMRI.
METHODS
A series of standard dental materials was studied on a 1.5 T MRI system using spin echo and gradient echo pulse sequences and their magnetic susceptibility was estimated using the geometric method. Measurements on samples of dental materials were supported by in vivo examples obtained in dedicated dMRI procedures.
RESULTS
The tested materials showed a range of distortion degrees. The following materials were classified as fully compatible materials that can be present even in the tooth of interest: the resin-based sealer AH Plus(®) (Dentsply, Maillefer, Germany), glass ionomer cement, gutta-percha, zirconium dioxide and composites from one of the tested manufacturers. Interestingly, composites provided by the other manufacturer caused relatively strong distortions and were therefore classified as compatible I, along with amalgam, gold alloy, gold-ceramic crowns, titanium alloy and NiTi orthodontic wires. Materials, the magnetic susceptibility of which differed from that of water by more than 200 ppm, were classified as non-compatible materials that should not be present in the patient's mouth for any dMRI applications. They included stainless steel orthodontic appliances and CoCr.
CONCLUSIONS
A classification of the materials that complies with the standard grouping of materials according to their magnetic susceptibility was proposed and adopted for the purposes of dMRI. The proposed classification can serve as a guideline in future dMRI research.
Topics: Alloys; Artifacts; Chromium Alloys; Composite Resins; Crowns; Dental Alloys; Dental Amalgam; Dental Materials; Epoxy Resins; Glass Ionomer Cements; Gold Alloys; Gutta-Percha; Humans; Image Enhancement; Magnetic Resonance Imaging; Magnetics; Metal Ceramic Alloys; Nickel; Orthodontic Brackets; Orthodontic Wires; Root Canal Filling Materials; Stainless Steel; Titanium; Zirconium
PubMed: 23610088
DOI: 10.1259/dmfr.20120271 -
Dental Materials Journal Jan 2021In this study, retentive forces were compared between telescopic crowns (TSC) made with poly(ether ether ketone) (PEEK) using computer-aided design and manufacturing and...
In this study, retentive forces were compared between telescopic crowns (TSC) made with poly(ether ether ketone) (PEEK) using computer-aided design and manufacturing and type 4 gold alloy using the conventional method. The retentive forces of TSCs were evaluated by performing a pull-out test with primary and secondary crowns. Initial retentive force was approximately 12 N for both PEEK and gold alloy TSCs. The retentive force of PEEK TSC was approximately 6.5 N after 10,000 cycles of insertion and removal. The reduction rate in retentive force was smaller for gold alloy TSC. PEEK TSC displayed greater surface roughness on the primary crown compared to the gold alloy TSC. Surface roughness slightly increased at the cervical margin after repetitive insertion and removal. The retentive force of PEEK TSC was smaller than gold alloy TSC, however the retentive force of PEEK TSC was adequate for stabilizing dental prostheses even after 10,000 cycles.
Topics: Crowns; Dental Stress Analysis; Ether; Gold Alloys; Ketones
PubMed: 32863374
DOI: 10.4012/dmj.2019-298 -
European Journal of Orthodontics Aug 2014To investigate the composition and the microstructural and mechanical characterization of three different types of lingual brackets.
OBJECTIVES
To investigate the composition and the microstructural and mechanical characterization of three different types of lingual brackets.
MATERIALS AND METHODS
Incognito™ (3M Unitek), In-Ovation L (DENTSPLY GAC) and STb™ (Light Lingual System, ORMCO) lingual brackets were studied under the scanning electron microscope employing backscattered electron imaging and their elemental composition was analysed by energy-dispersive X-ray microanalysis. Additionally, Vickers hardness was assessed using a universal hardness-testing machine, and the indentation modulus was measured according to instrumented indentation test. Two-way analysis of variance was conducted employing bracket type and location (base and wing) as discriminating variable. Significant differences among groups were allocated by post hoc Student-Newman-Keuls multiple comparison analysis at 95% level of significance.
RESULTS
Three different phases were identified for Incognito and In-Ovation L bracket based on mean atomic number contrast. On the contrary, STb did not show mean atomic contrast areas and thus it is recognized as a single phase. Incognito is a one-piece bracket with the same structure in wing and base regions. Incognito consists mainly of noble metals while In-Ovation L and STb show similar formulations of ferrous alloys in wing and base regions. No significant differences were found between ferrous brackets in hardness and modulus values, but there were significant differences between wing and base regions. Incognito illustrated intermediate values with significant differences from base and wing values of ferrous brackets.
CONCLUSIONS/IMPLICATIONS
Significant differences exist in microstructure, elemental composition, and mechanical properties among the brackets tested; these might have a series of clinical implications during mechanotherapy.
Topics: Algorithms; Chromium; Chromium Alloys; Copper; Dental Alloys; Dental Stress Analysis; Elastic Modulus; Electron Probe Microanalysis; Gold Alloys; Hardness; Humans; Iron; Materials Testing; Microscopy, Electron, Scanning; Nickel; Orthodontic Appliance Design; Orthodontic Brackets; Surface Properties
PubMed: 24232131
DOI: 10.1093/ejo/cjt086 -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Jun 2014The purpose of this study is to investigate the influence of cryogenic treatment and age-hardening heat treatment on the corrosion behavior of a dental casting Ag-Pd...
OBJECTIVE
The purpose of this study is to investigate the influence of cryogenic treatment and age-hardening heat treatment on the corrosion behavior of a dental casting Ag-Pd alloy.
METHODS
A low gold content dental casting alloy composed of Ag-Pd-Cu-Au was prepared for this study. Corrosion test was performed according to ISO 10271:2001 dental metallie-corrosion test methods. Experimental specimens were casted according to a standard dental lost-wax casting procedure, treated with solution by heating the specimens to 900 degrees C, and immediately quenched in ice water. The specimens were then divided into four groups and subjected to heat treatment, cryogenic treatment, and heat treatment combined with cryogenic treatment. The specimens after the solution treatment were taken as control. The metallographic structures of the specimens were observed. The electrochemical parameters and the quantity of non-precious metallic ions released were evaluated via electrochemical and static immersion tests.
RESULTS
Metallographic observation revealed that all the treatments resulted in a change in the microstructure of the alloy. The treatments were effective in improving the electrochemical parameters, such as an increase in Eocp and Ecorr and a decrease in Icorr (P < 0.05). The amount of non-noble metal ions released showed no difference compared with the control group (P > 0.05).
CONCLUSION
After different treatments, the antierosion properties of the alloy satisfied the ISO requirements. Age-hardening heat treatment and cryogenic treatment improved the corrosion resistance of the alloy.
Topics: Alloys; Copper; Corrosion; Dental Alloys; Gold Alloys; Hot Temperature; Palladium; Silver
PubMed: 25033637
DOI: 10.7518/hxkq.2014.03.007