HESI General Chairside Assisting Practice Exam

Zinc is the metal in amalgam powder that plays a significant role in suppressing oxidation. When zinc is added to dental amalgam, it reacts with moisture during the initial setting phase, which helps to prevent the oxidation of other metals in the amalgam. This property of zinc is particularly valuable because it enhances the longevity and strength of the dental restoration by maintaining the integrity of the amalgam mixture.

In contrast, copper, silver, and aluminum do not possess the same oxidation-reducing properties as zinc. Copper is primarily used to enhance the strength and reduce corrosion of the amalgam, while silver contributes to the strength and improves the aesthetic appearance. Aluminum, on the other hand, is generally not used in dental amalgams due to its reactive nature and lack of beneficial properties when mixed with other metals in dental applications. Thus, zinc's unique ability to suppress oxidation makes it an essential component in amalgam formulations.