The research aims to compare the inflammatory status of visceral adipose tissue from obese patients depending on the presence and severity of periodontitis, in order to establish a potential causal link between the severity of the bacterial contamination and insulin resistance.

Recruitment of patients will be achieved in the department of digestive surgery. It will involve 122 patients with severe obesity undergoing bariatric surgery scheduled within the digestive surgery department. Patients recruited will be examined for evaluating the presence and severity of periodontitis, and separated into either group 1: for patients with moderate or severe periodontitis, and or group 2: for patients without or with mild periodontitis. The day before the surgery, blood sample will be collected for the analysis of circulating metabolic and inflammatory markers. Collection of stimulated saliva, periodontal sample and faeces samples (50 g) will also be carried out for bacteria determination. During the surgical procedure, a sample of visceral adipose tissue (50 g) will be collected and used for periodontal bacteria detection and inflammatory markers analyses.

Inclusion Criteria:

• Patient eligible for bariatric surgery scheduled within the digestive surgery
• Patient affiliated to Social Security system or equivalent

Exclusion Criteria:

• Treatment with steroids or anti-inflammatory drugs in progress (or stopped for less than one month)
• Patients who received antibiotics within 3 months prior to the bariatric surgery for whatever duration
• Dental current (or older than 3 months)
• Participation in another research protocol