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Home > All Images > 1998 > July > 29 Jul 1998

Images Dated 29th July 1998

Choose from 22 pictures in our Images Dated 29th July 1998 collection for your Wall Art or Photo Gift. All professionally made for Quick Shipping.

Polarised LM of a cracked ceramic dental crown Featured 29 Jul 1998 Print

Polarised LM of a cracked ceramic dental crown

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