Used interdental brush. Coloured scanning electron micrograph (SEM) of a bristles from a used interdental brush. They are covered in dental plaque. Plaque consists of a film of bacteria embedded in a glycoprotein matrix. The matrix is formed from bacterial secretions and saliva. Plaque is the main cause of tooth decay. The bacteria feed on sugars in food, producing acid as a waste product. This acid corrodes the teeths enamel coating, resulting in dental caries. A buildup of dental plaque can also lead to inflamed and infected gums. Severe gum disease can lead to teeth falling out. Magnification: x45 when printed at 10 centimetres wide.