The primary objective of this case-control intervention study to explore the effectiveness of non surgical periodontal therapy on the gingival crevicular fluid (GCF) levels of sclerostin in patients with chronic periodontitis (CP) so as to get a more detailed insight into its diagnostic and prognostic potential as a biomarker of periodontal disease.

All individuals underwent a full-mouth periodontal examination, which included probing pocket depth (PPD), clinical attachment level (CAL), plaque index (PI), gingival index (GI), bleeding on probing (BOP). Individuals were categorized into three groups: individuals with clinically healthy periodontium (group 1), patients with chronic periodontitis (group 2), and group 3 consisted of the patients with chronic periodontitis (group 2), treated by scaling and root planning. GCF samples in grup 1 were taken at baseline. In group 2, GCF samples were taken before and after non- surgical periodontal treatment. Sclerostin, OPG and RANKL levels were determined using the enzyme-linked immunosorbent assay.

Inclusion Criteria:

• Criteria for the healthy group were GI = 0, PPD and CAL ≤ 3 mm, and no signs of attachment and bone loss
• Criteria for the chronic periodontitis group were clinical signs of inflammation, such as red color and swelling of the gingival margin, GI ≥ 2, PPD and CAL ≥ 5 mm with bone loss (>30% of the existing teeth)

Exclusion Criteria:

• Aggressive periodontitis, systemic diseases (i.e., diabetes mellitus, cancer, human immunodeficiency virus, bone-related diseases that compromise sclerostin, OPG or RANKL levels and collagen-metabolic diseases, or disorders), chronic high-dose steroid therapy, radiation or immunosuppressive therapy, allergy or sensitivity to any drug, pregnancy, lactation, and current smoking, smoking within the past 5 years. The individuals had no history of periodontal therapy or drug therapy (e.g. anti-inflammatory, antibiotic treatment or any other pharmacological treatment) for at least six months.