Final answer:
Mercury acts as a wetting agent in dental amalgams, promoting even distribution of other alloy particles, while silver and tin control dimensional changes of the amalgam.
Step-by-step explanation:
In dental amalgams, an alloy of mercury with one or more other metals is used to fill cavities in teeth. Liquid mercury acts as the wetting agent. As a wetting agent, the mercury facilitates the incorporation of the fine particles of the powdered alloy consisting of silver, tin, and copper, ensuring they are evenly distributed throughout the mixture, allowing for better adhesion to the tooth structure.
The role of controlling dimensional changes in a dental amalgam is typically attributed to silver and tin. These metals alloy with the mercury and control the expansion or contraction of the amalgam as it sets, which is critical for the durability and functionality of the filling.