Coloured scanning electron micrograph (SEM) of material collected from an infected periodontal pocket using a paper point. Amongst the non-keratinised epithelial cells (pink) are numerous bacteria (yellow, green red and blue). Periodontal pockets are spaces that form between the tooth and gum in cases of periodontitis (gum disease). The picture was created as part of a cooperation with Quintessenz Publishing. Magnification: x1,400 when printed at 15cm wide.