A filling is a method of restoring normal function and appearance to a tooth that has been damaged by caries.
When your dentist fills you, he first removes the decayed tooth tissue. It cleans the affected area and fills the cavity with filling material.
It also tries to prevent the progression of caries by closing the gaps that bacteria can enter with a filling.
The materials used for the filling are gold, porcelain, composite resin (tooth-colored filling) and amalgam. (an alloy of mercury silver, copper, tin, and sometimes zinc).