Dental plaque may be described as structured resilient yellow, grayish substance adhering to the tooth surface. The mineralized dental plaque is referred to as dental calculus. Bacteria within the biofilm are usually in understanding with the host immune response, disease occurs when this harmony is disrupted. These biofilm bacteria contribute around 80% of the total bacterial infection. The important biofilm related infection in the oral cavity are dental caries and periodontitis. This article will enlighten your knowledge on history, structure, classification, formation, composition, diagnosis and therapy of dental biofilm.