Clinical Research Directory

Inclusion Criteria: * Individuals aged 18 to 65 years * Presence of at least 20 natural teeth, excluding third molars * Being systemically healthy * Provision of written informed consent * For the periodontitis group, diagnosis of generalized Stage III Grade B periodontitis according to the 2017 AAP/EFP classification * Clinical attachment loss of at least 2 mm at two or more non-adjacent teeth for the periodontitis group * Interdental clinical attachment loss of at least 5 mm and periodontitis-related loss of no more than four teeth for Stage III periodontitis * A radiographic bone loss-to-age ratio between 0.25 and 1.00 for Grade B periodontitis * For the healthy control group, an intact periodontium, probing depth of 3 mm or less, and bleeding on probing at less than 10% of sites Exclusion Criteria: * Use of antibiotics, antimicrobial agents, nonsteroidal anti-inflammatory drugs, steroids, immunosuppressants, beta-blockers, calcium channel blockers, anticoagulants, or hormonal contraceptives within the previous 3 months * Periodontal treatment within the previous 6 months * Surgical periodontal treatment within the previous 12 months * Current smoking * Pregnancy or breastfeeding * Presence of any neurological, autoimmune, metabolic, inflammatory, or other systemic condition that could affect the immune response * Use of an orthodontic appliance