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Sun D, Frankel GS, Brantley WA, Heshmati RH, Johnston WM. Electrochemical impedance spectroscopy study of corrosion characteristics of palladium-silver dental alloys. J Biomed Mater Res B Appl Biomater 2021; 109:1777-1786. [PMID: 33817975 DOI: 10.1002/jbm.b.34837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 02/02/2021] [Accepted: 03/06/2021] [Indexed: 01/01/2023]
Abstract
Electrochemical impedance spectroscopy (EIS) has been used to obtain insight into corrosion processes for three Pd-Ag alloys, and compare their behavior with an Au-Pd alloy. Five specimens of each alloy received clinically-appropriate simulated porcelain-firing heat treatment. EIS testing was performed at ambient temperature, using 0.09% NaCl, 0.9% NaCl and Fusayama solutions. EIS data are presented as Bode plots. At the open-circuit potential (OCP), the data fit a modified Randles equivalent electrical circuit with a constant phase element (CPE), and the charge-transfer resistance (RCT ) and the two CPE parameters (CPE-T and CPE-P) were determined. The area-normalized capacitance of the double layer (Cdl ) was also calculated. The EIS data at two relevant elevated potentials in the passive range were also found to fit well a modified Randles equivalent circuit with different values for the charge transfer resistance and CPE parameters. At the OCP no significant effect on RCT was found for the alloys and electrolytes, and both alloy and electrolyte significantly affected CPE-P. In vitro corrosion was controlled by charge transfer and charge accumulation processes, and the behavior differed at the elevated potentials compared to the OCP. Significant effects were found for alloy, electrolyte, and alloy/electrolyte interaction on Cdl at the OCP. The EIS parameters at elevated potentials indicate that the Pd-Ag alloys should have satisfactory clinical corrosion resistance. The EIS analyses yielded information about in vitro corrosion of these alloys that cannot be obtained from potentiodynamic polarization testing.
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Affiliation(s)
- Desheng Sun
- Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - Gerald S Frankel
- Department of Materials Science and Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - William A Brantley
- Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - Reza H Heshmati
- Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
| | - William M Johnston
- Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio, USA
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Tufekçi E, Mitchell JC, Olesik JW, Brantley WA, Monaghan P, Johnston WM. ICP-MS measurements of elemental release from two palladium alloys into a corrosion testing medium for different solution volumes and agitation conditions. J Prosthet Dent 2021; 128:522-528. [PMID: 33597079 DOI: 10.1016/j.prosdent.2020.12.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 12/02/2020] [Accepted: 12/03/2020] [Indexed: 11/18/2022]
Abstract
STATEMENT OF PROBLEM The in vivo release of Pd from palladium alloys into the oral environment and sensitivity reactions by patients has been of concern. However, little information is available about the variation in elemental release from different palladium alloys. PURPOSE The purpose of this in vitro study was to compare the elemental release into a corrosion-testing medium from a high-palladium alloy (Freedom Plus, 78Pd-8Cu-5Ga-6In-2Au) and a Pd-Ag alloy (Super Star, 60Pd-28Ag-6In-5Sn) under different conditions. MATERIAL AND METHODS Alloys were cast into Ø12×1-mm-thick disks, subjected to simulated porcelain-firing heat treatment, polished, and ultrasonically cleaned in ethanol. Three specimens of each alloy were immersed for 700 hours in a solution for in vitro corrosion testing (ISO Standard 10271) that was maintained at 37 °C. Two solution volumes (125 mL and 250 mL) were used, and the solutions were subjected to either no agitation or agitation. Elemental compositions of the solutions were analyzed by using inductively coupled plasma-mass spectroscopy (ICP-MS). Concentrations of released elements from each alloy for the 2 solution volumes and agitation conditions were compared by using the restricted maximum likelihood estimation method with a 4-way repeated-measures ANOVA, the Satterwhite degrees of freedom method, a lognormal response distribution, and the covariance structure of compound symmetry. RESULTS For the 4 combinations of solution volume and agitation conditions, the mean amount of palladium released was 3 orders of magnitude less for the Pd-Ag alloy (0.009 to 0.017 μg/cm2 of alloy surface) compared with the Pd-Cu-Ga alloy (17.9 to 28.7 μg/cm2). Larger mean amounts of Sn, Ga, Ag, and In (0.29 to 0.39, 0.57 to 0.83, 0.71 to 1.08, and 0.91 to 1.25 μg/cm2, respectively) compared with Pd were released from the Pd-Ag alloy. Smaller amounts of Cu, Ga, and In (4.8 to 9.9, 5.9 to 12.8, and 4.2 to 9.5 μg/cm2, respectively) compared with Pd were released from the Pd-Cu-Ga alloy. The Ru released was much lower for the Pd-Ag alloy (0.002 μg/cm2) than the Pd-Cu-Ga alloy (0.032 to 0.053 μg/cm2). Statistically significant differences (P<.001) in elemental release were found for the factors of alloy and element and the alloy×element interaction. Significant differences were found for the solution volume (P=.022), solution volume×element interaction (P=.022), and alloy×solution volume×element interaction (P=.004). No significant effect was found for agitation condition. CONCLUSIONS The relative amounts of released elements from each alloy were not proportional to the relative amounts in the composition. The amounts of Pd and Ga released from the Pd-Cu-Ga alloy were consistent with the breakdown of a Pd2Ga microstructural phase and perhaps some dissolution of the palladium solid solution matrix. Precipitates, rather than the palladium solid solution matrix, appeared to undergo greater dissolution in the Pd-Ag alloy. The Pd-Ag alloy should have lower risk of adverse biological reactions than the Pd-Cu-Ga alloy.
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Affiliation(s)
- Eser Tufekçi
- Professor, Department of Orthodontics, Virginia Commonwealth University, School of Dentistry, Richmond, Va; Formerly, Section of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio
| | - John C Mitchell
- Professor and Associate Dean, College of Dental Medicine, Midwestern University, Glendale, Ariz; Formerly, Department of Geological Sciences, The Ohio State University, Columbus, Ohio
| | - John W Olesik
- Research Scientist, Trace Element Research Laboratory, School of Earth Sciences, The Ohio State University, Columbus, Ohio
| | - William A Brantley
- Professor Emeritus, Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio.
| | - Peter Monaghan
- Sherman Dental Associates, Evanston, Ill; Formerly, Section of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio
| | - William M Johnston
- Professor Emeritus, Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio
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Sun D, Brantley WA, Frankel GS, Heshmati RH, Johnston WM. Potentiodynamic polarization study of the corrosion behavior of palladium-silver dental alloys. J Prosthet Dent 2018; 119:650-656. [DOI: 10.1016/j.prosdent.2017.06.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 10/18/2022]
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Nierlich J, Papageorgiou SN, Bourauel C, Hültenschmidt R, Bayer S, Stark H, Keilig L. Corrosion behavior of dental alloys used for retention elements in prosthodontics. Eur J Oral Sci 2016; 124:287-94. [PMID: 27061513 DOI: 10.1111/eos.12267] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2016] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to investigate the corrosion behavior of 10 different high noble gold-based dental alloys, used for prosthodontic retention elements, according to ISO 10271. Samples of 10 high-noble and noble gold-based dental alloys were subjected to: (i) static immersion tests with subsequent analysis of ion release for eight different elements using mass spectrometry; (ii) electrochemical tests, including open-circuit potential and potentiodynamic scans; and (iii) scanning electron microscopy, followed by energy-dispersive X-ray microscopy. The results were analyzed using one-way ANOVA and Sidak multiple-comparisons post-hoc test at a level of significance of α = 0.05. Significant differences were found among the 10 alloys studied for all ions (P < 0.001). The potentiodynamic analysis showed values from -82.5 to 102.8 mV for the open-circuit potential and from 566.7 to 1367.5 mV for the breakdown potential. Both the open-circuit and the breakdown potential varied considerably among these alloys. Scanning electron microscopy analysis confirmed the existence of typically small-diameter corrosion defects, whilst the energy-dispersive X-ray analysis found no significant alteration in the elemental composition of the alloys. The results of this study reveal the variability in the corrosive resistance among the materials used for retention elements in prosthodontics.
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Affiliation(s)
- Judith Nierlich
- Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany
| | - Spyridon N Papageorgiou
- Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany.,Department of Orthodontics, School of Dentistry, University of Bonn, Bonn, Germany
| | - Christoph Bourauel
- Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany
| | - Robert Hültenschmidt
- Department of Prosthetic Dentistry, Preclinical Education and Materials Science, School of Dentistry, University of Bonn, Bonn, Germany
| | - Stefan Bayer
- Department of Prosthetic Dentistry, Preclinical Education and Materials Science, School of Dentistry, University of Bonn, Bonn, Germany
| | - Helmut Stark
- Department of Prosthetic Dentistry, Preclinical Education and Materials Science, School of Dentistry, University of Bonn, Bonn, Germany
| | - Ludger Keilig
- Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany.,Department of Prosthetic Dentistry, Preclinical Education and Materials Science, School of Dentistry, University of Bonn, Bonn, Germany
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Milheiro A, Muris J, Kleverlaan CJ, Feilzer AJ. Influence of shape and finishing on the corrosion of palladium-based dental alloys. J Adv Prosthodont 2015; 7:56-61. [PMID: 25722839 PMCID: PMC4341188 DOI: 10.4047/jap.2015.7.1.56] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 10/08/2014] [Accepted: 10/10/2014] [Indexed: 11/13/2022] Open
Abstract
PURPOSE The purpose of this study was to evaluate the effects of the surface treatment and shape of the dental alloy on the composition of the prosthetic work and its metallic ion release in a corrosive medium after casting. MATERIALS AND METHODS Orion Argos (Pd-Ag) and Orion Vesta (Pd-Cu) were used to cast two crowns and two disks. One of each was polished while the other was not. Two as-received alloys were also studied making a total of 5 specimens per alloy type. The specimens were submersed for 7 days in a lactic acid/sodium chloride solution (ISO standard 10271) and evaluated for surface structure characterization using SEM/EDAX. The solutions were quantitatively analysed for the presence of metal ions using ICP-MS and the results were statistically analysed with one-way ANOVA and a Tukey post-hoc test. RESULTS Palladium is released from all specimens studied (range 0.06-7.08 µg·cm-2·week-1), with the Pd-Cu alloy releasing the highest amounts. For both types of alloys, ion release of both disk and crown pairs were statistically different from the as-received alloy except for the Pd-Ag polished crown (P>.05). For both alloy type, disk-shaped pairs and unpolished specimens released the highest amounts of Pd ions (range 0.34-7.08 µg·cm-2·week-1). Interestingly, in solutions submerged with cast alloys trace amounts of unexpected elements were measured. CONCLUSION Shape and surface treatment influence ion release from dental alloys; polishing is a determinant factor. The release rate of cast and polished Pd alloys is between 0.06-0.69 µg·cm-2·week-1, which is close to or exceeding the EU Nickel Directive 94/27/EC compensated for the molecular mass of Pd (0.4 µg·cm-2·week-1). The composition of the alloy does not represent the element release, therefore we recommend manufacturers to report element release after ISO standard corrosion tests beside the original composition.
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Affiliation(s)
- Ana Milheiro
- Department of Dental Materials Science, ACTA, University of Amsterdam and VU University Amsterdam, Nederland
| | - Joris Muris
- Department of Dental Materials Science, ACTA, University of Amsterdam and VU University Amsterdam, Nederland
| | - Cornelis J Kleverlaan
- Department of Dental Materials Science, ACTA, University of Amsterdam and VU University Amsterdam, Nederland
| | - Albert J Feilzer
- Department of Dental Materials Science, ACTA, University of Amsterdam and VU University Amsterdam, Nederland
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Ntasi A, Jabbari YA, Mueller WD, Eliades G, Zinelis S. Metallurgical and electrochemical characterization of contemporary silver-based soldering alloys. Angle Orthod 2014; 84:508-15. [PMID: 24199746 PMCID: PMC8667485 DOI: 10.2319/073013-569.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 09/01/2013] [Indexed: 10/27/2023] Open
Abstract
OBJECTIVE To investigate the microstructure, hardness, and electrochemical behavior of four contemporary Ag-based soldering alloys used for manufacturing orthodontic appliances. MATERIALS AND METHODS The Ag-based alloys tested were Dentaurum Universal Silver Solder (DEN), Orthodontic Solders (LEO), Ortho Dental Universal Solder (NOB), and Silver Solder (ORT). Five disk-shaped specimens were produced for each alloy, and after metallographic preparation their microstructural features, elemental composition, and hardness were determined by scanning electron microscopy with energy-dispersive X-ray (EDX) microanalysis, X-ray diffraction (XRD) analysis, and Vickers hardness testing. The electrochemical properties were evaluated by anodic potentiodynamic scanning in 0.9% NaCl and Ringer's solutions. Hardness, corrosion current (Icorr), and corrosion potential (Ecorr) were statistically analyzed by one-way analysis of variance and Tukey test (α=.05). RESULTS EDX analysis showed that all materials belong to the Ag-Zn-Cu ternary system. Three different mean atomic contrast phases were identified for LEO and ORT and two for DEN and NOB. According to XRD analysis, all materials consisted of Ag-rich and Cu-rich face-centered cubic phases. Hardness testing classified the materials in descending order as follows: DEN, 155±3; NOB, 149±3; ORT, 141±4; and LEO, 136±8. Significant differences were found for Icorr of NOB in Ringer's solution and Ecorr of DEN in 0.9% NaCl solution. CONCLUSION Ag-based soldering alloys demonstrate great diversity in their elemental composition, phase size and distribution, hardness, and electrochemical properties. These differences may anticipate variations in their clinical performance.
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Affiliation(s)
- Argyro Ntasi
- PhD Graduate Student, Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Youssef Al Jabbari
- Director, Dental Biomaterials Research and Development Chair, Associate Professor, Prosthetic Dental Sciences Department, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Wolf Dieter Mueller
- Director, Dental and Biomaterials Research Group Dental School, “Charite” Medical University of Berlin, Germany
| | - George Eliades
- Professor and Director, Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Spiros Zinelis
- Assistant Professor, Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece, and Consultant, Dental Biomaterials Research and Development Chair, King Saud University, Riyadh, Saudi Arabia
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Abstract
In the biomedical field, palladium has primarily been used as a component of alloys for dental prostheses. However, recent research has shown the utility of palladium alloys for devices such as vascular stents that do not distort magnetic resonance images. Dental palladium alloys may contain minor or major percentages of palladium. As a minor constituent, palladium hardens, strengthens and increases the melting range of alloys. Alloys that contain palladium as the major component also contain copper, gallium and sometimes tin to produce strong alloys with high stiffness and relatively low corrosion rates. All current evidence suggests that palladium alloys are safe, despite fears about harmful effects of low-level corrosion products during biomedical use. Recent evidence suggests that palladium poses fewer biological risks than other elements, such as nickel or silver. Hypersensitivity to palladium alone is rare, but accompanies nickel hypersensitivity 90-100% of the time. The unstable price of palladium continues to influence the use of palladium alloys in biomedicine.
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Affiliation(s)
- John C Wataha
- University of Washington School of Dentistry, Seattle, WA, USA.
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Joska L, Poddana M, Leitner J. Corrosion behavior of palladium–silver–copper alloys in model saliva. Dent Mater 2008; 24:1009-16. [DOI: 10.1016/j.dental.2007.11.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Revised: 11/27/2006] [Accepted: 11/21/2007] [Indexed: 10/22/2022]
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Berzins DW, Kawashima I, Graves R, Sarkar NK. Heat treatment effects on electrochemical corrosion parameters of high-Pd alloys. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2008; 19:335-41. [PMID: 17597363 DOI: 10.1007/s10856-006-0054-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Accepted: 11/27/2006] [Indexed: 05/16/2023]
Abstract
This research determined the effect oxidation, as that occurs during porcelain firing, has upon the corrosion parameters of Pd-based ceramic alloys and how it may relate to Pd allergy. The 20 h open circuit potential (OCP), 20 h corrosion rate (Icorr), and anodic polarization (E-i) curves of 11 commercial Pd alloys were measured in a phosphate buffered saline solution. The alloys were divided into the following four groups based upon composition: PdGa(Ag), PdCu, PdAg, and AuPd and tested in both as-cast and oxidized conditions. In both the as-cast and oxidized conditions, the OCP of Ag-containing Pd alloys is significantly lower than non Ag-containing high-Pd alloys. The OCP of all alloys increased after oxidation. With regard to corrosion rate, the Ag-containing alloys showed a decrease in Icorr with oxidation. In contrast, three of the four non Ag-containing high-Pd (>or=74 wt%) alloys exhibited a higher Icorr. A comparison of the anodic polarization curves showed only the alloys containing larger amounts (>or=16 wt%) of Ag displayed a notable difference between as-cast and oxidized states. Oxidation as required during porcelain-fused-to-metal device preparation alters the electrochemical characteristics of the alloys studied. This alteration may be of importance with regard to their potential for Pd allergy.
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Affiliation(s)
- D W Berzins
- Dental Biomaterials, School of Dentistry, Marquette University, 113A Wehr Physics Building, Milwaukee, WI 53201-1881, USA.
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Al-Hity RR, Kappert HF, Viennot S, Dalard F, Grosgogeat B. Corrosion resistance measurements of dental alloys, are they correlated? Dent Mater 2007; 23:679-87. [PMID: 16876241 DOI: 10.1016/j.dental.2006.06.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Accepted: 06/14/2006] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The aim was to assess in vitro the resistance to corrosion of eight commercial dental alloys by two quantitative methods, electrochemical and immersion tests, then to statistically test the hypothesis of possible correlation between the polarization resistance (R(p)) and the elemental release. METHODS Two quantitative methods; electrochemical and immersion test, were used. From the first, after recording the OCP during 24h immersion in acidified artificial saliva (pH 2.3), R(p) was obtained using the linear polarization in anodic path and applying the Mansfeld's method. From the static immersion test, using the same test solution, the elemental release from was analysed and determined using the ICP-AES. Thereafter, the two measurements were used to plot the regression line and to determine the correlation coefficient. The significance of the correlation was tested using F-test at a confidence interval of 0.99. RESULTS : The resistance to corrosion results obtained from the two methods were ranked and compared; an inverse relation between them was evident. Then, the obtained coefficient of correlation (R(2)) was 0.886. With the F-test at 0.99 confidence interval, the hypothesis was accepted as the calculated F was about 44 against critical F=13.7. CONCLUSION The correlation between the two measurements, R(p) and mass loss, was proved statistically significant. This result may provide a new approach to predict the corrosion behaviour of dental alloys by firstly using the easier methods.
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Affiliation(s)
- Rafah R Al-Hity
- LEIBO, EA 637, Faculté d'Odontologie de Lyon, rue Gauillaume Paradin, 69008 Lyon, France.
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Lu HB, Li Y, Wang FH. Influence of composition on corrosion behavior of as-cast Cu–Zr alloys in HCl solution. Electrochim Acta 2006. [DOI: 10.1016/j.electacta.2006.05.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Joska L, Marek M, Leitner J. The mechanism of corrosion of palladium–silver binary alloys in artificial saliva. Biomaterials 2005; 26:1605-11. [PMID: 15576134 DOI: 10.1016/j.biomaterials.2004.05.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2004] [Accepted: 05/26/2004] [Indexed: 11/21/2022]
Abstract
Palladium dental casting alloys are alternatives to gold alloys. The aim of this study was to determine the electrochemical behaviour and the corrosion mechanism of binary silver-palladium alloys. Seven binary silver-palladium alloys and pure palladium and silver were tested in a model saliva solution. Electrochemical tests included corrosion potential, polarization resistance, and potentiodynamic polarization measurements. The corrosion products, which may be theoretically formed, were determined by thermodynamic calculation. The behaviour of silver and silver-rich alloys was dominated by the preferential formation of a thiocyanate surface layer, which controlled the free corrosion potential. Palladium dissolved in the form of a thiocyanate complex, but the surface became passivated by either palladium oxide or solid palladium thiocyanate layer, the thermodynamic calculations indicating preference for the oxide. Palladium-rich alloys showed evidence of silver depletion of the surface, resulting in behaviour similar to palladium. Examination of binary silver-palladium alloys has made possible determination of the role of the components of the alloys and model saliva in the corrosion behaviour. The findings are applicable to the more complex commercial dental alloys containing silver and palladium as major components.
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Affiliation(s)
- L Joska
- Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Technicka 5, 166 28 Prague 6, Czech Republic.
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Viennot S, Dalard F, Lissac M, Grosgogeat B. Corrosion resistance of cobalt-chromium and palladium-silver alloys used in fixed prosthetic restorations. Eur J Oral Sci 2005; 113:90-5. [PMID: 15693835 DOI: 10.1111/j.1600-0722.2005.00190.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The corrosion resistance of a cobalt-chromium (Co-Cr) alloy was assessed with a view to determining its potential use in the manufacture of fixed dental prostheses. The electrochemical behaviour of the alloy was compared with that of two palladium (Pd)-based alloys. Measurements of corrosion potential and anodic polarization were performed on the alloys, and the specimen surfaces were examined by using scanning electron microscopy. Although the corrosion potential of the Co-Cr alloy was lower than that of the Pd-based alloys, the corrosion currents and polarization resistance values were similar for all three alloys. All materials showed a very high resistance to corrosion. Given that the beneficial mechanical properties of Co-Cr alloys have already been established, this type of alloy may be a suitable alternative for use in the manufacture of fixed dental prostheses.
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Affiliation(s)
- Stéphane Viennot
- Laboratoire d'Etude des Interfaces et des Biofilms en Odontologie (EA 637) - Faculté d'Odontologie, Université Claude Bernard Lyon I, Rue Guillaume Paradin, F-69372 Lyon Cedex 08, France
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Sun D, Monaghan P, Brantley WA, Johnston WM. Potentiodynamic polarization study of the in vitro corrosion behavior of 3 high-palladium alloys and a gold-palladium alloy in 5 media. J Prosthet Dent 2002; 87:86-93. [PMID: 11807489 DOI: 10.1067/mpr.2002.121239] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
STATEMENT OF PROBLEM Corrosion of cast alloy restorations may lead to their failure or adversely affect their biocompatibility. Although some documentation of the corrosion behavior of the high-palladium dental alloys exists, questions remain about their corrosion resistance and mechanisms. PURPOSE This study compared the in vitro corrosion characteristics of 3 high-palladium alloys and 1 gold-palladium alloy in simulated body fluid and oral environments. MATERIAL AND METHODS Two Pd-Cu-Ga alloys and 1 Pd-Ga alloy were selected; an Au-Pd alloy served as the control. The corrosion behavior for the as-cast and simulated porcelain-firing (heat-treated) conditions of each alloy (N = 5) was evaluated in 0.9% NaCl, 0.09% NaCl, and Fusayama solutions. Heat-treated specimens of each alloy (N = 5) were also tested in N(2)-deaerated 0.09% NaCl and Fusayama solutions (pH 4). After immersion in the electrolyte for 24 hours, the open-circuit potential (OCP) was measured, and linear polarization was performed from -20 mV to +20 mV (vs. OCP) at a scanning rate of 0.125 mV/s. Cyclic polarization was performed from -300 mV to +1000 mV and back to -300 mV (vs. OCP) at a scanning rate of 1 mV/s. Data were evaluated with analysis of variance and the Ryan-Einot-Gabriel-Welsch multiple-range test (alpha=.05). RESULTS The OCP of each alloy varied with the condition (as-cast or heat-treated) and electrolyte used. Corrosion resistance was similar for the 4 alloys tested. For cyclic polarization, all alloys showed active-passive or spontaneous passive behavior in nearly all electrolytes. During some reverse scans, the 3 high-palladium alloys displayed 3 or 5 anodic peaks. No positive hysteresis was observed for any of the alloy/electrolyte combinations evaluated. CONCLUSION The corrosion resistances of the 3 high-palladium alloys in simulated body fluid and oral environments were comparable to that of the gold-palladium alloy. The similar corrosion resistance for the 3 high-palladium alloys was attributed to their high noble metal content and theorized stable structure at the submicron level. Selective corrosion of different phases and elements, surface enrichment of palladium, and adsorption of species are possible corrosion mechanisms. The cyclic polarization results suggest that none of the 4 alloys would be prone to pitting or crevice corrosion under in vivo conditions, but crevice conditions should nonetheless be avoided for these alloys in the oral environment.
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Affiliation(s)
- Desheng Sun
- Oral Biology Program, College of Dentistry, The Ohio State University, Columbus, Ohio 43210, USA
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