Dental amalgam is a traditional silver-coloured filling that has been used for over a century. There is some debate as to the safety of amalgam due to the fact that it includes mercury. Mercury is a poison but in fillings it is mixed with other metals in a way which changes its chemical structure. Many studies have investigated its safety and to-date no controlled study has found a connection between amalgam fillings and any medical problem.
Recent years has seen great improvement in white filling materials (composites) and the most recent materials can now be used successfully in back teeth.