White fillings are made of Composite Resin. They provide a great aesthetic alternative to older silver (amalgam) filling material.
The Composite Resins have improved substantially over past decade and can last just as long as amalgam fillings. Although very durable, Composite Restoration may need to be replaced every 7-10 years depending on the size of the restoration.
If the tooth is heavily broken down, a crown may be a better choice of treatment.