Influence of Topical Fluorides on corrosion behaviour of silver amalgam alloys

✍ Scribed by Dr. E. Khamis; Dr. M. Seddik

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 304 KB
• Volume: 27
• Category: Article
• ISSN: 0933-5137
• DOI: 10.1002/mawe.19960270711

✦ Synopsis

Abstract

Potentiodynamic polarization and cyclic voltametry measurements were employed to study the effect of topical fluoride preparations on corrosion of silver amalgam alloy in synthetic saliva and aqueous fluoride solutions. Results support that small amounts of copper and indium alloyed to silver – tin amalgam enhance corrosion resistance considerably. Indiloy shifts both the open circuit potential and the anodic polarization curve to more positive potential values, this lead to a decreases in the current density. The weak activity of Indiloy as compared with Spheraloy is attributed to the fact that the amount of γ~2~ phase (tin–mercury) present in the former is much lesser than that present in the latter. Findings also show that fluoride solutions (NaF, SnF and SnF + HCI) enhance the dissolution rate of the investigasted alloys and the polarization curves illustrate the appearance of an active – passive transitions. This behaviour was discussed on the basis of complex formation. Cyclic voltammograms confirm the results obtained from the potentiodynamic polarization measurements and elucidate the anodic oxidation peaks of silver oxide and copper verifying the proposed mechanism.