What material is known to cause contraction of amalgam?

The material known to cause the contraction of amalgam is tin. In dental amalgam formulations, tin acts as a critical component that influences the physical properties of the mixture, including thermal expansion and contraction behavior. When amalgam sets, the presence of tin can lead to a decrease in volume, resulting in contraction as the material hardens. This characteristic is important because it can affect the margin stability and adaptation of the amalgam to the cavity preparation.

Other metals in the amalgam do not have the same contraction properties. Silver primarily contributes to the strength and corrosion resistance of the amalgam, while copper enhances the overall strength and decreases corrosion. Zinc, on the other hand, has more to do with preventing oxidation and controlling moisture during the amalgam setting process but does not induce contraction. Understanding the effects of these materials helps dental professionals optimize amalgam compositions for improved clinical performance.