A tooth-colored composite resin filling will actually bond chemically to the tooth, whereas with amalgam (silver) fillings retention has to be created, thus possibly removing sound tooth structure.
A tooth-colored filling needs a more conservative preparation of the tooth and can even strengthen the tooth internally. You will also be very pleased with the appearance of a tooth-colored restoration. You won't even be able to tell that it is there!
- from JJ K. (Dental Assistant)