[On the clinical relevance of the dimensional behavior of silver amalgam. A comparative in vitro and in vivo study].

The clinical relevance of the dimensional behavior of six different gamma-2-free silver amalgam products was examined in comparative in vitro and in vivo trials. Dye penetration tests, roughness measurements, and inspection of the marginal fit using a scanner electron microscope all showed that the results of the in vivo and the in vitro trials were in good agreement and that there was no significant difference between the various products tested, despite the fact that they differed both in morphology and in composition. Copalite exerts a favorable influence on the marginal fit of amalgam restorations, not only in laboratory trials, but also clinically. The results obtained show that the behavior of an amalgam with respect to changes in volume is not the sole criterion by which its quality is to be judged. Amalgams with a pronounced contraction tendency will seal the marginal gap with their corrosion products (SnCl). Here copalite serves as a temporary stand-in. There was no leakage of metal ions from the restoration into the dentin for any of the products tested, including those with a high copper content.