A filling is a way to restore a tooth damaged by decay back to its normal function and shape. When a dentist gives you a filling, he or she first removes the decayed tooth material, cleans the affected area, and then fills the cleaned out cavity with a filling material.
By closing off spaces where bacteria can enter, a filling also helps prevent further decay. Materials used for fillings include gold, porcelain, a composite resin (tooth-colored fillings), and an amalgam (an alloy of mercury, silver, copper, tin and sometimes zinc).
Only your dentist can detect whether you have a cavity that needs to be filled. During a checkup, your dentist will use a small mirror to examine the surfaces of each tooth.
Anything that looks abnormal will then be closely checked with special instruments. Your dentist may also X-ray your entire mouth or a section of it. The type of treatment your dentist chooses will depend on the extent of damage caused by decay.