When teeth are damaged beyond what a filling can restore, crowns are often required. Crowns are placed over a damaged tooth, completely covering the tooth and strengthening it. Newer technology allows for crowns to be milled from a solid block of material, which provides excellent strength and esthetics. Before a crown can be placed on a tooth, the tooth must be made slightly smaller in all dimensions, so that when the crown is placed over the tooth the overall size of the crowned tooth remains the same. Crowns are held tightly to the tooth with dental cement, and aren't intended to be removed. Traditional crowns can be all gold, all porcelain, or a combination of porcelain over gold. Crowns are an excellent restoration for a badly damaged tooth, or teeth with extremely large fillings.