Inclusion Criteria:  Age > 18 years. Smoker patients (> 9 cigarettes per day). At least 10 years of continued periodontal maintenance therapy. Diagnosis of generalized chronic periodontitis or gingivitis. Patient had undergone active periodontal therapy comprised of non-surgical and/or surgical therapy.  Exclusion Criteria:  Patients with bisphosphonate therapy. Patients with chemo or radiotherapy. Patients with hormonal therapy. Patients with a history of refractory periodontitis or repeated abscess formation. Patients with debilitating diseases that could impair the immune system (HIV/AIDS, cancer, or autoimmune diseases).