Inclusion Criteria:  Presence of periodontitis Good general health At least 19 remaining teeth Written informed consent forms  Exclusion Criteria:  Antibiotics or anti-inflammatory medications use within the preceding 3 months Periodontal therapy within the previous 6 months Purulent exudation from periodontal pockets Pregnancy and breastfeeding Presence of severe, uncontrolled (decompensated) diseases of the internal organs, or neuropsychiatric disorders Presence of other conditions that determined the inability of the patient to understand the nature and possible consequences of the study