Restorative materials have traditionally led the charge in changing the way in which dental patients are treated. Composite resin had largely supplanted the older silicate restoration by the early 1970s, as a result of its superior durability and aesthetics. Today, we are witnessing a worldwide shift away from amalgam restorations. Amalgams are durable, easy to place, and safe when properly prepared and placed. But can they continue to be used in the face of the public's growing fear of "mercury fillings"? Neither metallurgical science, nor a century of data showing amalgam restorations to be generally safe and cost-effective, means much to antiamalgam activists, not all of whose claims can be dismissed as irrational. Some concerns are valid, such as the environmental impact of residual mercury in improperly mixed amalgam.
In the case of amalgam, I see the choice of restorative material being based increasingly on preference rather than evidence. The preference could be that of the individual patient (which we have seen evolving in the United States) or that of the electorate, implemented by government fiat. On the other hand, environmental issues could ultimately trump all others.