A composite resin is a tooth-coloured plastic mixture filled with glass (silicon dioxide) first introduced in the 1960s. Originally only used for front teeth because of their softer nature, modern improvements to their composition make them generically suitable today.
Composite fillings are more difficult to place than silver fillings so may take your dentist 15-20 minutes longer to complete and because they are considered to be a cosmetic treatment, they are not available on the NHS and must be paid for.
The main advantage of composite fillings is their aesthetic appeal. The main disadvantage is their life expectancy. White fillings have always been considered less long lasting than silver amalgam fillings but there are now new materials available with properties comparable to silver amalgam, and these are proving to be very successful. The life expectancy of your composite filling can depend on the depth of cavity and its position in the mouth; your dentist is best positioned to advise you.