Corrosion evaluation of recasting non-precious dental alloys. 1995

E Khamis, and M Seddik
College of Science, Chemistry Department, King Saud University, Riyadh, Kingdom of Saudi Arabia.

The effect of recasting, up to four times, non precious Ni-Cr and Co-Cr commercial dental alloys on their corrosion behaviour in saliva and saline media was carried out. A potentiokinetic technique was utilised to analyse the electrochemical characteristics of the anodic polarisation curves of these alloys. A considerable anodic polarisation range (about 2.0 V vs SCE) was used to investigate the possibility of developing a passive regime at such high potential range. The most important feature noted was a rapid rise in current density above a certain critical potential called pitting potential, Ep. The experimental data show that the open circuit potential, Eoc does not enable differentiation between the corrosion resistance of the four alloys used in this study. However, Ep and the rupture potential Er does distinguish between them. Increasing the number of the successive recastings of Wirolloy leads to enhancing the pitting potential, thus, the corrosion resistance of Wirolloy (Ni-Cr) improves after remelting and recasting. It has been found that Wirolloy corrodes 26 times faster than Wironit alloy under the same solution. The alloys containing cobalt and molybdenum show higher corrosion resistance than those containing nickel. Additionally, their corrosion resistance was not affected by successive melting and recasting. In chloride solutions Ni-Cr alloys show a high susceptibility to pitting corrosion, while Co-Cr alloys show a noble behaviour. The corrosion resistance of the four non precious alloys were in the following order: Biocast > Wironit > Cobond > Wirolloy.

UI MeSH Term Description Entries
D008422 Materials Testing The testing of materials and devices, especially those used for PROSTHESES AND IMPLANTS; SUTURES; TISSUE ADHESIVES; etc., for hardness, strength, durability, safety, efficacy, and biocompatibility. Biocompatibility Testing,Biocompatible Materials Testing,Hemocompatibility Testing,Testing, Biocompatible Materials,Testing, Hemocompatible Materials,Hemocompatibility Testings,Hemocompatible Materials Testing,Materials Testing, Biocompatible,Materials Testing, Hemocompatible,Testing, Biocompatibility,Testing, Hemocompatibility,Testing, Materials,Testings, Biocompatibility
D009532 Nickel A trace element with the atomic symbol Ni, atomic number 28, and atomic weight 58.69. It is a cofactor of the enzyme UREASE.
D002858 Chromium Alloys Specific alloys not less than 85% chromium and nickel or cobalt, with traces of either nickel or cobalt, molybdenum, and other substances. They are used in partial dentures, orthopedic implants, etc. Chromium-Cobalt Alloys,Chromium-Nickel Alloys,Cobalt-Chromium Alloys,Nickel-Chromium Alloys,Alloys, Chromium,Alloys, Chromium-Cobalt,Alloys, Chromium-Nickel,Alloys, Cobalt-Chromium,Alloys, Nickel-Chromium,Chromium Cobalt Alloys,Chromium Nickel Alloys,Cobalt Chromium Alloys,Nickel Chromium Alloys
D003035 Cobalt A trace element that is a component of vitamin B12. It has the atomic symbol Co, atomic number 27, and atomic weight 58.93. It is used in nuclear weapons, alloys, and pigments. Deficiency in animals leads to anemia; its excess in humans can lead to erythrocytosis. Cobalt-59,Cobalt 59
D003343 Corrosion The gradual destruction of a metal or alloy due to oxidation or action of a chemical agent. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed) Corrosions
D003735 Dental Casting Technique The process of producing a form or impression made of metal or plaster using a mold. Casting Technic, Dental,Casting Technics, Dental,Casting Technique, Dental,Casting Techniques, Dental,Dental Casting Technic,Dental Casting Technics,Dental Casting Techniques,Technic, Dental Casting,Technics, Dental Casting,Technique, Dental Casting,Techniques, Dental Casting
D004563 Electrochemistry The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes. Electrochemistries
D012463 Saliva The clear, viscous fluid secreted by the SALIVARY GLANDS and mucous glands of the mouth. It contains MUCINS, water, organic salts, and ptylin. Salivas
D012464 Saliva, Artificial A solution used for irrigating the mouth in xerostomia and as a substitute for saliva. Artificial Saliva
D017743 Equipment Reuse Further or repeated use of equipment, instruments, devices, or materials. It includes additional use regardless of the original intent of the producer as to disposability or durability. It does not include the repeated use of fluids or solutions. Product Recycling,Recycling, Equipment,Equipment Reusability,Equipment Recycling,Recycling, Product,Reusability, Equipment,Reuse, Equipment

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