#TOOTH crown Your dentist may suggest providing a crown for a tooth in order to either restore a badly damaged tooth, to improve appearance of a tooth, or to build up the biting surface of a tooth. The natural tooth needs to be reduced by about 1-2mm to accommodate the crown, which fits over the top of the tooth (like a thimble) to strengthen & support the remaining tooth. Crowns can be made of porcelain, precious metal or a combination of porcelain thermally fused to precious metal, a bonded crown. Very occasionally, an acrylic (plastic) crown may be made.