Dental plaque is mainly caused by the activity of various microorganisms in the oral cavity. The formation of dental plaque is a complex dynamic process, the initial stage of which is the formation of an acquired membrane. The acquired membrane is a cell-free homogeneous biofilm formed from glycoproteins and other components of saliva, which selectively adheres to the tooth surface. By adhering the acquired mass of bacteria to the membrane on the tooth surface, different strains of bacteria adsorb to the acquired membrane at different rates. The selective adsorption of bacteria is due, in part, to the presence of receptors in the bacterial surface components that are complementary to the membranes obtained. When the bacteria are firmly attached to the obtained film, they can cause aggregation and locally increase up to ten layers, finally forming dental plaque. Good oral hygiene is very important, plaque can not be easily rinsed away with water, only through mechanical removal, patients are advised to go to the dental hospital in time for treatment.