Dental crown. Polarised light micrograph (PLM) of a longitudinal section through a tooth (yellow & blue) with a dental crown (grainy area). The ceramic crown is attached to the tooth by a layer of cement (dark brown). If the top of a tooth is badly cracked, decayed or broken, it must be replaced by an artificial crown. The remaining undamaged part of the tooth is cut down to a peg to receive the hollow crown. This crown is then shaped to form a replica of the original tooth and cemented in place. Magnification: x20 at 6.5x5cm size.
