They'll never know they're there
A composite, or resin based, filling (also known as a white filling) is a tooth-colored plastic mixture filled with glass (silicon dioxide) and is a composite quartz resin that usually contains some sort of light sensitive agent.
Composites are not only used to restore decayed areas, but are also used for cosmetic improvements of the smile by changing the color of the teeth or reshaping disfigured teeth. A composite filling can be tinted to match any tooth color and it forms a natural bond with the existing tooth in a way that metal fillings cannot. The end result is nearly invisible fillings.
Composite fillings tend to be used as an alternative to metal, or silver amalgam, fillings and are used to treat decay on a portion of a tooth, replace an old silver amalgam filling and to maintain a white smile.
Composite fillings are more than just attractive and they have distinct advantages over other types of fillings, especially metal ones. Composite fillings are environmentally non-toxic because they use no mercury. They are stronger because they bond directly to the surface of the tooth. They protect the tooth from fracturing because they don't require the severe "undercut" (removal of healthy tooth structure) of mercury fillings.