IL-1β and S1P Levels After Periodontal Therapy: A Split-Mouth Study

Gingival Crevicular Fluid Sphingosine-1-phosphate and Interleukin-1 Beta Levels After Non-surgical Periodontal Therapy: a Split-mouth Randomized Trial

This randomized split-mouth clinical trial aimed to evaluate the changes in interleukin-1 beta (IL-1β) and sphingosine-1-phosphate (S1P) levels in gingival crevicular fluid (GCF) following non-surgical periodontal therapy (NSPT) in patients with stage III periodontitis. A total of 17 systemically healthy, non-smoking individuals were included. For each patient, three diseased and three healthy periodontal sites were selected, totaling 51 diseased and 51 healthy sites for biochemical and clinical evaluation.

GCF samples and clinical periodontal parameters were collected at baseline, one month, and three months after NSPT. The levels of IL-1β and S1P were quantified using enzyme-linked immunosorbent assay (ELISA). The study also investigated the correlation between biomarker levels and clinical indicators of periodontal disease severity, such as probing depth and clinical attachment level.

Diseased sites were selected based on the most severe clinical findings, including probing depth (PD) of ≥6 mm, clinical attachment level (CAL) of ≥5 mm, and the presence of bleeding on probing (BOP). Healthy sites were defined by PD ≤3 mm, no clinical attachment loss, absence of radiographic bone loss, and BOP negativity. All selected sites were non-adjacent and distributed throughout the oral cavity to reduce regional bias.

This study also aimed to explore site-specific changes in biomarker expression over time and assess the correlation between GCF IL-1β/S1P levels and clinical indicators of periodontal disease severity and healing response. All GCF sampling was repeated from the same sites at each time point. Control (healthy) site sampling was done at baseline and 3 months, while diseased site sampling was conducted at baseline, 1 month, and 3 months.

Inclusion Criteria:

• Aged between 45 and 60 years
• Systemically healthy individuals with no known systemic conditions
• Non-smokers or former smokers who had quit at least two years prior
• Diagnosed with Stage III periodontitis according to the 2017 World Workshop Classification
• Presence of at least three diseased sites with probing depth (PD) ≥ 6 mm, clinical attachment level (CAL) ≥ 5 mm, and bleeding on probing (BOP [+])
• Presence of at least three periodontally healthy sites with PD ≤ 3 mm, no CAL, and no BOP
• No periodontal treatment within the last 6 months
• Provided written informed consent

Exclusion Criteria:

• Presence of systemic diseases known to affect periodontal status (e.g., diabetes mellitus, cardiovascular disease, autoimmune disorders)
• Use of antibiotics or anti-inflammatory medications within the last 6 months
• History of periodontal surgery within the past 12 months
• Pregnant or lactating women
• Current smokers or individuals who quit less than two years ago
• Sites with endodontic lesions, caries extending to the cervical area, trauma-related gingival recession, or bone loss due to non-periodontal causes
• Undergoing orthodontic treatment during the study period