Dental plaque, coloured scanning electron micrograph (SEM). Plaque consists of a film of bacteria (pink) embedded in a glycoprotein matrix. One of the bacteria in this sample is Fusobacterium nucleatum. 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.