Aluminium amalgam aluminium and reduce H from water, creating aluminium hydroxide (Al(OH)) and hydrogen gas (H). The electrons from the aluminium reduce mercuric Hg ion to metallic mercury. The metallic mercury can then form an amalgam with the exposed aluminium metal. The amalgamated aluminium then is oxidized by water, converting the aluminium to aluminium hydroxide and releasing free metallic mercury. The generated mercury then cycles through these last two steps until the aluminium metal supply is exhausted. Due to the reactivity of aluminium amalgam, restrictions are placed on the use and handling of mercury in proximity with aluminium. In particular, large amounts
Amalgam (dentistry) conservative preparation would be beneficial, composite is the recommended restorative material. These situations would include small occlusal restorations, in which amalgam would require the removal of more sound tooth structure, as well as in "enamel sites beyond the height of contour". For cosmetic purposes, composite is preferred when a restoration is required on an immediately visible portion of a tooth. Dental amalgam does not by itself bond to tooth structure. This was recognized as a shortcoming by early practitioners such as Baldwin. He recommended that the prepared cavity be coated with zinc phosphate cement just prior to filling with amalgam,