Biofilms are the collections of bacteria and other microorganisms that assemble on surfaces. They are widespread in nature and can colonize natural, nonliving hard surfaces such as river rocks, man-made surfaces like the concrete found in industrial pipelines, and even plant and animal surfaces and, of course, the teeth and gums.Within this broad definition, dental plaque falls into one of many types of different biofilms. Loosely adherent plaque and the denser, more firmly attached plaque mass are also considered biofilms. However, they are different in the types of organisms that inhabit them, their strength, and the likelihood that they might detach either spontaneously, through application of normal oral forces, or through oral cleaning