Used wax dental floss with dental plaque (yellow), bacteria (orange) and cheek cells (pink) on the dental floss fibres (blue), coloured scanning electron micrograph (SEM). Plaque consists of a biofilm of bacteria embedded in a glycoprotein matrix. The matrix is formed from bacterial secretions and saliva. The microorganisms that form the plaque biofilm are almost entirely bacteria (mainly Streptococcus mutans and other anaerobes) with the composition varying by location in the mouth. Plaque is the main cause of tooth decay. The bacteria feed on sugars in food, producing acid (lactic acid) as a waste product. This acid corrodes the teeth's enamel coating, resulting in dental cavities. A build-up of dental plaque can also lead to inflamed and infected gums. Severe gum disease can lead to periodontal disease and teeth falling out. Magnification: x70 when shortest axis printed at 25 millimetres.