Periodontal diseases are complex chronic pathologies presenting a high prevalence worldwide. Etiopathological process involved in initiation and progression of these multifactorial diseases are not well understood, explaining the huge clinical forms variability and the complexity of the currently used classification of periodontal diseases. Recently, the implication of antimicrobial peptides (AMPs) have been suggested as potential track of explanation for periodontal diseases pathogeny. The here presented study explore the level of expression of genes coding those peptides by studying periodontal smears obtained from healthy and periodontitis patients.

This study explore the level of expression of genes coding those peptides by studying Messenger RNA (mRNA) purified from periodontal smears obtained from healthy and periodontitis patients by "Masterpure©" protocol.After reverse transcription (RT-PCR), in-silico design of primers and specificity and efficiency calculation, Complementary DNA (cDNA) are quantified by a semi-quantitative method (delta-delta CT) vs a Housekeeping gene. Wilcoxon-Mann & Whitney tests and Chi² tests are performed to check the significativity of the results between groups.

Inclusion Criteria:

• Patients suffering of moderate to severe chronic periodontitis as described by the classification Armitage-1999, aged 35-65yo

Exclusion Criteria:

• Pregnant females, patients suffered from any other systemic diseases (cardiovascular, pulmonary, liver, cerebral, diseases or diabetes, cancer)
• patients that had received antibiotic treatment in the previous 3 months or who were taking long-term anti-inflammatory drugs; who had received a course of periodontal treatment or orthodontics treatment within the last 6 months; who were heavy smokers (>5 cig/day)