Wellcome Trust Blog

ToothThis worryingly cracked-looking surface shows us what a tooth looks like under a scanning electron microscope (SEM).

It was taken in the 1980s by David Gregory and Debbie Marshall, used as part of a poster for Dental Hygiene for the University of Aberdeen. The tooth had to be painstakingly prepared by being chemically fixed, washed with distilled water and dried using ethanol and carbon dioxide. It was then mounted on an aluminium stub and coated with 20nm (0.00002mm) platinum fragments. You can also find a coloured version of this image on Wellcome Images.

This tooth had just been extracted by a dental surgeon so was not at its healthiest. The surface is probably not actually cracked, but covered in calculus. Calculus (in this case, nothing to do with algebra) is a hard calcium deposit that builds up on everyone’s teeth. Calculus forms when dental plaque hardens. Dental plaque is a…

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