A filling is the name of a dental procedure in which a material such as silver amalgam or a composite (white) filling is used to treat a decayed tooth. This material is inserted into the tooth where it then prevents the further spread of decay or repairs any damage.
This treatment stops the decay from spreading into the root where it will cause a serious infection, e.g. an abscess. This also removes the need for a tooth extraction.
The silver amalgam filling is the traditional type of filling which is composed of various metals such as copper, tin and mercury. This combination helps to retain the normal function of the tooth.
The composite white filling is a synthetic combination of acrylic resin and glass which has a white colour thereby enabling it to match the colour of the tooth. This is also chosen for aesthetic reasons as many people prefer to have fillings which match the rest of their teeth rather than the distinctive silver filling.