Abstract: Periodontitis is a chronic infectious disease caused by plaque microorganisms, which often leads to progressive destruction of periodontal supporting tissue. Its clinical manifestations include gingival inflammation, periodontal pocket formation, loss of attachment and alveolar bone resorption. It is the primary cause of adult tooth loss. Plaque biofilm, as the initiation factor of periodontitis, is an essential factor causing periodontitis. Dental plaque biofilm is the basis of survival, metabolism and pathogenicity of oral bacteria, which is composed of many architectural ecological groups growing in order with each other. It is important to study the formation of dental plaque biofilm for the prevention and treatment of periodontitis. Not all bacteria in the dental plaque biofilm can directly adhere to the surface of the acquired film. According to the colonization time, the bacteria can be divided into early, middle and late colonization bacteria. Fusobacterium nucleatum (f.nucleatum), as a intermediate colonizing bacterium, is the bridge bacterium connecting the early and late colonizing bacteria, which has important significance in the formation process of dental plaque biofilm. In this paper, the role of Fusobacterium nucleatum in the formation process of dental plaque biofilm is summarized.

Key words: Fusobacterium nucleatum, periodontitis, Microcosm biofilm, Gene expression