Amalgam stained dentin: a proper substrate for bonding resin composite?

Nowadays the use of dental amalgam is mostly abandoned and substituted by tooth colored resin composites that can be bonded to teeth tissues by adhesive techniques.
The aim of this thesis was to find out whether dark stained dentin, as often observed after removal of amalgam restorations and attributed to penetration of corrosion products, is an adequate substrate for bonding resin composite restorations.
Previous studies revealed tin and zinc as main metals from amalgam in stained dentin and showed strong relation between presence of corrosion products and demineralized state of dentin. In an in-vitro study these findings were confirmed. However, the intensity of staining showed week correlation with concentration of metals.
Another in-vitro study, with amalgam placed upon artificially demineralized dentin, showed staining only in demineralized specimens.
Bond strength testing of three adhesive systems to dentin, that was demineralized by dental caries decay, showed product specific results and for two adhesives lower bond strength than to sound dentin. Another bond strength test revealed no differences in bond strength to amalgam stained and sound dentin for all adhesive strategies tested, but product depending differences in failure patterns.
A clinical study showed good performance of extensive resin composite restorations upon amalgam removal, without adhesion related failures.
It is concluded that staining of dentin does not negatively affect bond strength of resin composites in spite of differences in composition of stained and sound or caries affected dentin. It is anticipated that tin and zinc from amalgam have prosperous effects on demineralized dentin.