Why do dentists use mercury to do amalgam fillings?

"Ingredients": Mercury is one of the metals contained in the alloy of amalgam fillings. There is some controversy over whether or not is is released from the amalgam; however, nothing has ever been clincally proven to be harmful.

They are safe.: Mercury helps to keep the dental amalgam in a state where it can be manipulated when placed into your tooth. The metal then hardens giving you a solid structure to protect and seal your tooth from further decay.