Dental amalgam is the traditional silver-coloured filling we are all familiar with. Although there is mercury in dental amalgam, once it is combined with the other materials in the amalgam filling its chemical nature is changed rendering it harmless. Research into the safety of dental amalgam has been carried out for over a century and to date, no trustworthy controlled studies have found a connection between amalgam fillings and any medical problem.
Whilst composite (tooth coloured) fillings are becoming more popular, amalgam fillings represent the most durable and long-lasting form of filling available. (Apart from gold fillings which are more expensive.)
Amalgam fillings are the only type of filling provided through the NHS, composite fillings are considered to be 'cosmetic' and therefore must be paid for.