When cavities are small, fillings are necessary to help keep tooth decay from spreading. If the cavity is large or affects several tooth surfaces, a crown may be necessary. A crown covers the entire tooth like a cap.
Fillings and crowns may be white or silver. A white filling is called a composite filling and is designed to match the color of the tooth. White fillings may not be strong enough in certain situations and they do cost a little more so they may not be covered by certain dental plans. Silver fillings, called amalgam fillings are generally stronger and less costly than white fillings. They are often used on back teeth where chewing force requires stronger fillings.