Etiopathology of periodontitis is complex and various risk factors are known :

• Bacterial factors: major risk factor. Although the presence of periodontopathogen bacteria is necessary for the onset of periodontitis, these microorganisms are not sufficient for progression of all periodontal disease.
• Immune factor: host immune response modulates the disease evolution to destruction or recovery. The most studied cytokine in periodontology is IL-1 that induces various immune reactions and bone resorption directly or indirectly through the stimulation of prostaglandin E2 (PGE2) release. PGE2 activates the matrix metalloproteinases that are responsible of the degradation of bone extracellular matrix.

Cytokine production, especially TNFα, IL-1β, IL-6 and IL-8, by some immune cells is modulated by new identified molecules such as Triggering Receptor Expressed on Myeloid cells (TREM) whose role in periodontitis is unknown.

The purpose of this study is to compare concentrations of soluble TREM-1 and TREM-2 markers in infected sites and in healthy sites in patients affected by periodontitis.

Other purposes are

1. Comparison of soluble TREM-1 and TREM-2 concentrations in healthy sites in patients affected by periodontitis and in healthy patients
2. Comparison of soluble TREM-1 and TREM-2 concentrations before and after etiologic periodontitis treatment
3. Estimation of the correlation between soluble TREM-1 and TREM-2 concentrations and clinical signs of periodontitis
4. Description of soluble TREM-1/TREM-2 ratio before and after etiologic treatment
5. Description of presence of some bacteria in sites analyzed for soluble TREM-1 and TREM-2
6. Search for the most observed bacteria in presence of high concentrations of soluble TREM-1 and TREM-2 before and after etiologic treatment
7. Evaluation of the impact of psychological stress measured through salivary cortisol level in saliva on TREM-1 and -2 expression
8. Evaluation of the impact of psychological stress through stress and anxiety auto-questionnaires (Spielberger and Cohen) on soluble TREM-1 and TREM-2 concentrations in crevicular fluid of healthy and pathologic teeth.

Inclusion Criteria:

All:

• Affiliation to social security plan
• Absence of refusal of patient

Group 1. Periodontal patients:

• Affected by moderate to severe chronic periodontitis
• At least 2 distinct infected sites with periodontal pocket depth ≥ 5mm
• Having not received any root planing during last 6 months before visit

Group 2. Control:

• No periodontitis
• Consulting for dental checkup and eventually scaling

Exclusion Criteria:

All:

• Pregnant women (change in bacterial flora) and breast-feeding
• Administration of systemic antibiotherapy or any treatment influencing periodontal environment (anti-inflammatory, anti-epileptic, immune-suppressor, calcium inhibitor) during 6 months before sample collection
• Patients having a pathology needing a prophylactic antibiotherapy (possibly influencing the treatment)
• Teeth with periapical inflammatory lesions of endodontic origin
• Person under guardianship

Group 1. Periodontal patients:

- Root planing during last 6 months before visit

Group 2. Control:

- Periodontitis