Tooth decay Polarised light micrograph PLM of a longitudinal section through a molar tooth with dental caries or tooth decay The tooth consists of enamel orange covering the dentine blue and the pulp at bottom centre with its nerve fibres and blood vessels Tooth decay red black at centre is caused by the buildup of plaque which consists largely of food remains and bacteria The bacteria feed on the food particles producing acids as they break them down If untreated the acid will destroy the enamel and dentine exposing the pulp and causing intense pain Eventually the tooth will die Magnification x at xcm size