Periodontitis and Inflammation

Today, to understand pathogenic mechanisms involved in periodontitis and peri-implantitis remains a challenge to identify biomarkers or therapeutic targets to improve prevention and screening, as well as the effectiveness of periodontitis and peri-implantitis treatments. The aim is to characterize, in vivo, specific molecular markers reflecting the activity of the pathology, which could lead to * improve the knowledge of the pathogenesis of periodontitis and peri-implantitis; * determine target molecules involved in tissue destruction; * determine molecular profiles of patients at local and systemic risk; * determine therapeutic targets For this purpose, biological samples will be collected (plaque, saliva, crevicular fluid) from patients with periodontitis or peri-implantitis stage 3 or 4 versus patients with a healthy periodontium. Biological samples will be collected before and all along the periodontal or peri-implantal treatment. Gingiva explants collection will be sampling within the surgical procedures (if they are needed). The primary objective is to investigate tissue and cellular expression of molecular markers associated with periodontal destruction during periodontitis or peri-implantitis in relation to periodontal infection and systemic changes in host response. A characterization of the cytokines in gingival fluid and unstimulated saliva (Luminex® technique) of patients with periodontitis or peri-implantitis versus without periodontitis or peri-implantitis will be done. The secondary objective is to study the influence of periodontitis on systemic pathologies via serum analysis of molecules and bacteria involved in periodontal destruction. Immunofluorescence evaluation of protein expression and distribution (inflammatory mediators, inflammatory pathway signaling proteins) in gingival explants, characterization of proteases (MMP) present in gingival fluid and unstimulated saliva (Luminex® technique) and microbiological analysis of the subgingival biofilm (by quantitative PCR).