Amalgam used in dentistry is an alloy of silver, tin, copper and mercury. Although some patients are concerned about the presence of mercury in amalgam, the Australian Dental Association's policy, on the basis of available research, is that dental amalgam produces no harmful effects to one's health. In addition to this, the World Health Organisation, as well as the International Dental Federation, have released a joint statement confirming the safety of dental amalgam as a filling material. The Association believes that, other than for aesthetic reasons, there is no positive advantage in having dental amalgam fillings replaced with other materials.