Periodontitis and Inflammation: Study on Biological Samples

Periodontitis is a major public health problem because it is widespread in the adult population. It leads to the irreversible destruction of the anchoring tissues of the teeth, and represents a modifiable risk factor for systemic inflammatory pathologies. This chronic inflammatory disease, which is associated with oral dysbiosis involving Porphyromonas gingivalis, is triggered by a permissive immune response. It is preceded by a reversible clinical phase, during which there is no bone resorption process: gingivitis. The understanding of the key mechanisms involved in the evolution from gingivitis to periodontitis, which will allow to early identify patient at risk of periodontitis, remain unclear at this time. Neutrophils are the main cells of inflammation present within the periodontal pockets. The excess of certain neutrophils or the alteration of their functions is associated with the triggering of periodontitis, whereas their activity, finely orchestrated, would be a key to periodontal homeostasis. It is likely that some periodontal bacteria, including P. gingivalis, but also products of matrix catabolism could deregulate the physiological functions of neutrophils towards pro-inflammatory and catabolic profiles. Moreover, to date, the differentiation and role of neutrophil subsets in periodontal homeostasis as well as in gingivitis and its evolution into periodontitis remain poorly studied. The investigators hypothesize that various subsets of neutrophils may play different roles during the development of periodontitis (evolution of gingivitis to periodontitis). The primary objective is to characterize neutrophil subtypes associated with periodontal destruction during periodontitis. Secondary objectives are : 1. Identify specific interactions of tissue-activated neutrophils with the matrix microenvironment during periodontitis 2. Identify specific interactions of tissue or oral (salivary) activated neutrophils with the oral microbiota during periodontitis 3. Identify specific oral (salivary) neutrophil subtypes in periodontal health, gingivitis and periodontitis 4. Evaluate the function, including pro-osteoclastogenic function, of oral neutrophils compared to blood neutrophils stimulated by infection