Generally Fillings which are used on the teeth are of different types:
1) Silver fillings also called as Amalgam fillings (Black/Grey or Silver in color depending on perception!) They are strong and last a life time but loosing popularity now a days because of its color.
2) Glass Inomer fillings (G.I.C – off white in color) Fluoride containing Fillings!
3) Ceramic and composite fillings – same shade matching that of your teeth color. It is used for filling biting surface cavities, outer & inner wall cavities as well as to close gaps between 2 teeth or to repair chipped or fractured teeth. Used both for front and back teeth. They are very popularly called White Fillings !! It is chemically bonded on the tooth by etching, bonding & then using U.V. blue light to make the filling material stick on the tooth till they harden.