Dental fillings are dental restorative materials used to restore damaged or decayed tooth structure. Fillings are also used to repair cracked or broken teeth. Materials used in dental fillings are amalgam (a composition of mercury, silver, copper, tin), and composite resin (tooth-colored fillings).
Dental amalgams have been used since the 19th century, and composite fillings, first introduced in the 1960's have undergone many generational improvements.
Read more: http://www.zakdental.com/dental-fillings/