I have mercury fillings
Mercury (silver) fillings are made when metal powder and mercury are mixed. These fillings are unsightly and many people are concerned about the possible long term toxic effect of mercury.
Mercury fillings can be replaced by white (tooth coloured) fillings. White fillings are made mainly of glass particles, synthetic resin and a setting ingredient. There is also a bonding layer that bonds the white filling to the tooth structure.
White fillings have always been considered less long lasting than amalgam fillings but there are now new materials available with properties comparable to amalgam and these are proving to be very successful. The life expectancy of a white filling can depend greatly on where it is in your mouth and how heavily your teeth come together when you bite.