Dental plaque. Coloured scanning electron micrograph (SEM) of plaque, which consists of a film of bacteria (red) embedded in a matrix of glycoprotein (blue). The bacteria shown are mainly spindle-shaped Fusobacteria. If left untreated, bacteria in the plaque produce acids which erode dental enamel, leading to decay and infection. Magnification: x260 when printed 10 centimetres wide.