Figure 3.

The relationship between Fusobacterium nucleatum periodontal diseases and peri-implant diseases. Biofilms are universally accepted as mutual and critical factors in the initiation of periodontal and peri-implant diseases. The varied substrate for bacterial colonization and probably elevated function of Fusobacterium nucleatum in biofilm formation may be responsible for the reported discrepancies in its composition. With the succession of dental plaque, on the one hand, Fusobacterium nucleatum adheres to and/or invades host cells to induce mixed infection; on the other hand, invaded Fusobacterium nucleatum activates the human immune system to secrete inflammatory factors and accumulate inflammatory cells. These two effects cooperate with each other to elicit the ultimate inflammatory response. Detected differences between periodontal diseases and peri-implant diseases in histological structure and inflammatory response might indicate the specific pathogenesis of Fusobacterium nucleatum in these two diseases individually between the host infection and host response.