Study the effect of non-surgical periodontal therapy on cystatin C levels in gingival crevicular fluid and serum in both healthy patients and patients with renal impairment. The number of participants is 30 individuals, divided into three groups receiving conservative periodontal treatment (scaling and root planing):Systemically and periodontally healthy patients, Patients with periodontitis without systemic diseases, and Patients with periodontitis and chronic kidney disease. The study also aims to determine the relationship between the severity of periodontal disease and kidney function by measuring cystatin C levels, which is an important biomarker for both conditions. Additionally, it seeks to assess whether non-surgical periodontal therapy can be included in the treatment protocols for kidney patients to improve their quality of life.

Periodontal diseases, particularly gingivitis and periodontitis, are common inflammatory conditions affecting the tooth-supporting tissues. These diseases induce both local and systemic inflammatory responses, which may impact other organs, including the kidneys. Cystatin C (CSTC) is an inhibitor of cysteine proteases and is considered an important biomarker for kidney function, as its serum levels rise in cases of renal impairment. Periodontal diseases may contribute to elevated serum cystatin C levels due to systemic inflammation caused by bacterial infection and inflammatory mediators circulating in the bloodstream. On the other hand, non-surgical periodontal therapy (e.g., scaling and root planing) may reduce both local and systemic inflammation, potentially improving cystatin C levels and kidney function. This study aims to: Assess and compare cystatin C levels in serum and gingival crevicular fluid (GCF) among healthy individuals and patients with periodontitis، Examine the effect of non-surgical periodontal therapy on serum and GCF cystatin C levels in patients with renal impairment compared to healthy controls، and Analyze the relationship between periodontitis severity and kidney function by correlating cystatin C levels with other renal markers (e.g., glomerular filtration rate).

Inclusion Criteria:

• Patients with Stage II (Grade A or B) periodontitis (according to AAP 2017 classification).
• Age range: 20 to 70 years.
• No pathological tooth mobility.
• No furcation involvement caused by periodontal disease.
• No systemic diseases affecting periodontal or renal health.
• No systemic antibiotic use within the previous 3 months.
• No periodontal treatment within the previous 6 months

For Chronic Kidney Disease (CKD) Patients:

• Confirmed CKD diagnosis for at least 3 years (by a consultant nephrologist).
• Receiving conservative management (pre-dialysis).

Exclusion Criteria:

- Stage III or IV periodontitis.

• Grade C periodontal disease.
• Bone loss in more than 10 sites.
• Pathological tooth mobility (Grade II or III).
• Furcation involvement due to periodontal disease.
• Tooth loss due to periodontal disease.
• Heavy smoking (>10 cigarettes/day).
• Pregnancy or lactation.
• Patients undergoing dialysis.