Wellcome Image of the week: Tooth
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 biofilm of bacteria that builds up on the teeth, consisting of around a thousand different species of bacteria. These bacteria break down the sugar in our diet, and produce acid from this reaction. The acid damages the tooth, causing caries (tooth decay).
This image gives us a vivid reminder of the advice that dentists have been telling us for years: avoid sugary food and brush your teeth properly, else your teeth might end up needing to be removed like this one.