Inclusion Criteria:  Presence of a minimum of 15 natural teeth. At least four non-adjacent teeth sites in each jaw having CAL ≥ 5 mm and PD > 5 mm in one or more sites. Bleeding on probing (BOP) ≥ 30%. Tooth loss due to periodontitis ≤ 4 teeth. For smoker's patients; study will include patients who regularly smoked at least 10 cigarettes/day for a minimum of 5 years. For non-smokers patients; study will include patients who had never smoked.  Exclusion Criteria:  Individuals with a history of systemic diseases or immunological disorders. Individuals using hormone replacement therapy. Pregnant and lactating women. Individuals that received periodontal treatment within the last 6 months. Individuals with a history of systemic antibiotics and anti-inflammatory drugs within the last 3 months.