ABSTRACT The Ni-Cr-Mo alloys have been used as dental prostheses because they own a good mechanical strength, high corrosion resistance and even to be economically viable. These alloys corrosion protection against in salt solutions typical of physiological media is due to passivation phenomenon with an oxide surface layer formation, mainly chromium oxides. This protective film, subjected to a mechanical stress in a corrosive environment, can partially dissolve by releasing ions, which have deleterious effects in a human body. Fluoride ions, existing in hygiene products, change the buccal environment and their presence may enable a localized corrosion process initiation. The aim of this work has been to investigate the chemical composition influence of three alloys in corrosion resistance to: A (Ni-73% Cr-14% Mo-8.5% Be-1.8% Al-1.8%), B (Ni-61% Cr-25% Mo-10.5% Si-1.5%) and C (Ni-65% Cr-22.5% Mo-9.5%) in media containing fluorides that simulate mouthwashes solution. The study has been done in a 0.05% NaF solution, pH 6, at 37°C using electrochemical techniques. The alloy with the highest nickel and the lowest chromium content is not passive in the middle studied, showing a continuous increase in current density with the potential increasing, while the other alloys show passivation range of 600 mV and passive current density of about 10-6 A/cm2.
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nullN. Sampaio, J. Silva, H. Acciari, R. Nakazato, E. Codaro and H. de Felipe, "Influence of Ni and Cr Content on Corrosion Resistance of Ni-Cr-Mo Alloys for Fixed Dental Prostheses in 0.05% NaF Aqueous Solution," Materials Sciences and Applications, Vol. 1 No. 6, 2010, pp. 369-372. doi: 10.4236/msa.2010.16053.
 A. C. Fraker, “Corrosion of Metallic Implants and ProsThesis Devices,” In: ASTM International, Ed., ASTM Metals Handbook, Metals Park, Ohio, Vol. 13, 1987, pp. 1324-1335.
 M. F. Leclerc, “Surgical Implants,” In: ASTM International, Ed., ASTM Metals Handbook, Metals Park, Ohio, Vol. 02, 1987, pp.164-180.
 G. R. Baran, “The Metallurgy of Ni-Cr Alloys for Fixed Pros-Thodontics,” Journal of Prosthetics Dentistry, Vol. 50, No. 5, 1983, pp. 639-650.
 American Society of Metals, “Properties and Selection: Nonferrous Alloys and Special-Purpose Materials,” In: ASTM International, Ed., ASTM Metals Handbook, Metals Park, Ohio, Vol. 02, 1990.
 J. W. Schultze and M. M. Lohrengel, “Stability, Reactivity and Breakdown of Passive Films. Problems of Recent and Future Research,” Electrochimica Acta, 2000, Vol. 45, pp. 2499-2513.
 P. Schmuki, “From Bacon to Barriers: A Review on the Passivity of Metals and Alloys,” Journal of Solid State Eletrochemistry, Vol. 6, 2002, pp. 145-164.
 I. Milosev and H.-H. Strehblow, “The Behavior of Stainless Steels in Physiological Solution Containing Complexing Agent Studied by X-Ray Photoelectron Spectroscopy,” Journal of Biomedical Materials Research, Vol. 52, 2000, pp. 404-412.
 N. Chiff, B. Grosgogeat, M. Lissac and F. Dalard, “In fluence of Fluoridated Mouthwashes on Corrosion Resistance of Orthodontics Wires,” Biomaterials, Vol. 25, 2004, pp. 4335-4544.
 A. M. Al-Mayouf, A. A. Al-Swayih, N. A. Al-Mobarak and A. S. Al-Jabab “Corrosion Behavior of a New Titanium Alloy for Dental Implant Applications in Fluoride Media,” Materials Chemistry And Physics, Vol. 86, May 2004, pp. 320-329.
 M. C. R A. Rezende, A. P. R. Alves, E. N. Codaro and C. A M. Dutra, “Effect of Commercial Mouthwashes on the Corrosion Resistance of Ti-10Mo Experimental Alloy,” Mater.Science: Materials in Medicine, Vol. 18, 2007, pp. 149-154.
 H. H. Huang, “Surface Characterization of Passive Film on NiCr-Based Dental Casting Alloys,” Biomaterials, April 2003, Vol. 24, No. 9, pp. 1575-1582.
 L. Reclaru and J.-M. Meyer, “Study of Corrosion between a Titanium Implant and Dental Alloys,” J Dent, Vol. 22, March 1994, No. 3, pp. 159-168.
 S. P. Kedici, A. A. Aksüt, M. Ali Kílí?arslan, G. Bayramog Lu and K. G?kdemir, “Corrosion Behavior of Dental Metals and Alloys in different Media,” Journal of Oral Rehabilitation, October 1998, Vol. 25, pp. 800-808.
 K. J. Anusavice, Phillips materiais dentários, 10th Edition, Guanabara Koogan, Rio de Janeiro, 1998.