Tarnish
Pronunciation: TAR-nish
Surface discolouration of a metallic dental restoration caused by chemical reaction with oral compounds such as sulfides, chlorides, or oxides, without loss of material integrity.
Full Definition
Tarnish is a surface phenomenon affecting metallic restorations, characterised by colour change resulting from the formation of thin sulfide, oxide, or chloride films on the metal surface. Unlike corrosion, tarnish does not involve significant loss of material or structural degradation. In dental materials editing, the distinction between tarnish (surface discolouration) and corrosion (electrochemical degradation) is clinically and scientifically important. Authors sometimes use these terms interchangeably; editors should flag and correct such usage. Tarnish resistance is an evaluable property in alloy selection for restorations.
Usage
Usage note: Do not use 'tarnish' and 'corrosion' interchangeably. Tarnish implies surface discolouration without structural loss; corrosion implies electrochemical degradation and material loss.
In Context
- "The gold-palladium alloy demonstrated excellent tarnish resistance after 12 months in simulated oral fluid." — In vitro corrosion study
- "Authors used 'tarnish' and 'corrosion' synonymously throughout; these terms carry distinct meanings in dental metallurgy and were corrected accordingly." — Peer review note