Fillings these days are usually of the white (composite) filling materials. There is also of a white filling material that is called glass ionomer. These glass ionomers are extremely good on root sufaces, and release Fluoride, which helps keep down recurrent decay. Lastly, there are the amalgams. There are the “so called Mercury fillings”, although the old gamma 2 phase where mercury was released. They are rarely used anymore. All patients will have the pros and cons of each type explained to them prior to placing any of them. Some people are driven solely by what their insurance will pay. Sometime, this is just amalgam.