VOLKER STEGER / SCIENCE PHOTO LIBRARY VOLKER STEGER / SCIENCE PHOTO LIBRARY
Dental crown. Polarised light micrograph (PLM) of a longitudinal section through a cracked dental crown made of metal (multicoloured) and ceramic (above metal). 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. Here the crown has cracked during firing in a dental furnace. This is because the ceramic and metal parts of the crown have different rates of expansion. New dental ceramics must overcome this problem. Magnification: x20 at 5x7cm size.
Model release not required. Property release not required.