Assessment of corrosion resistance of cast cobalt- and nickel-chromium dental alloys in acidic environments

Research output: Contribution to journalArticle

Authors

Colleges, School and Institutes

External organisations

  • 1 Department of Restorative Dentistry, Faculty of Dental Surgery, University of Malta, Msida - Malta.
  • 2 Department of Metallurgy and Materials Engineering, Faculty of Engineering, University of Malta, Msida - Malta.

Abstract

BACKGROUND: The aim of this study was to compare the degradation resistance of nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) alloys used as a base material for partial dentures in contact with saliva.

METHODS: Wiron® 99 and Wironit Extra-Hard® were selected as representative casting alloys for Ni-Cr and Co-Cr alloys, respectively. The alloys were tested in contact with deionized water, artificial saliva and acidified artificial saliva. Material characterization was performed by X-ray diffractometry (XRD) and microhardness and nanohardness testing. The corrosion properties of the materials were then analyzed using open circuit potential analysis and potentiodynamic analysis. Alloy leaching in solution was assessed by inductively coupled plasma mass spectrometry techniques.

RESULTS: Co-Cr alloy was more stable than the Ni-Cr alloy in all solutions tested. Leaching of nickel and corrosion attack was higher in Ni-Cr alloy in artificial saliva compared with the acidified saliva. The corrosion resistance of the Co-Cr alloy was seen to be superior to that of the Ni-Cr alloy, with the former exhibiting a lower corrosion current in all test solutions. Microstructural topographical changes were observed for Ni-Cr alloy in contact with artificial saliva. The Ni-Cr alloy exhibited microstructural changes and lower corrosion resistance in artificial saliva. The acidic changes did not enhance the alloy degradation.

CONCLUSIONS: Ni-Cr alloys are unstable in solution and leach nickel. Co-Cr alloys should be preferred for clinical use.

Details

Original languageEnglish
Pages (from-to)47-54
Number of pages8
JournalJournal of applied biomaterials & functional materials
Volume16
Issue number1
Early online date26 Oct 2017
Publication statusPublished - Jan 2018

Keywords

  • Journal Article