It is common for the surface of teeth with large fillings to develop hairline cracks. By placing crowns on these teeth, pain can be relieved and full dental function can be restored. Stains or chips in the front teeth can cause embarrassment, while older fillings may weaken the structure of the tooth. A porcelain crown provides more support than porcelain veneers. When root canal fillings are placed in teeth, crowns can protect them from breaking.