Evaluation of the Clinical and Biochemical Efficacy of Repeated Injectable Platelet-Rich Fibrin Application Following Scaling and Root Planing in Patients With Periodontitis

A total of 20 patients diagnosed with Stage 3 Grade B Periodontitis based on clinical and radiographic findings will be included in this study at the Department of Periodontology, Faculty of Dentistry, Gülhane University. Eligible participants will be systemically healthy, non-smokers, not pregnant or breastfeeding, not on any medications, and must not have received any periodontal treatment or antibiotics within the past six months.

All participants will be informed about the study in detail, and written and verbal informed consent will be obtained from those who voluntarily agree to participate.

The study will be designed as a randomized controlled split-mouth clinical trial, in which the periodontal pockets in one half of the mouth will serve as the test site, and those in the other half will serve as the control site. Allocation of test and control sides will be determined by coin toss. Baseline and 3-month clinical periodontal parameters - including Plaque Index (PI), Gingival Index (GI), Bleeding on Probing (BOP), Probing Pocket Depth (PPD) and Clinical Attachment Level (CAL) will be recorded using a Williams periodontal probe.

For biochemical analysis, gingival crevicular fluid (GCF) samples will be collected from the deepest periodontal pockets at the test and control sites at four time points: baseline, 7 days after the first application of injectable platelet-rich fibrin (i-PRF), 7 days after the second application, and at 3 months. GCF collection will be performed using Periopaper strips after isolating the area with cotton rolls and gently removing supragingival plaque. Strips will be inserted into the pocket until resistance is felt, held in place for 15 seconds, and then analyzed for volume using a Periotron device. Samples will then be stored in Eppendorf tubes at -80°C until biochemical analysis. Levels of Platelet Factor-4 (PF-4), Myeloperoxidase (MPO), Transforming Growth Factor Beta (TGF-β), and Platelet-Derived Growth Factor (PDGF) in GCF will be analyzed using ELISA.

Following baseline measurements and GCF sampling, scaling and root planing (SRP) will be performed in two sessions, spaced one week apart, using standard ultrasonic and hand instruments (curettes and Gracey curettes).Venous blood samples (15 ml) will be drawn from the antecubital vein using sterile syringes and transferred into two plain tubes. The samples will be centrifuged at 1000 rpm for 3 minutes. The injectable platelet-rich fibrin (i-PRF) from the upper layer will be collected using a 5 ml syringe and administered into all deep periodontal pockets (≥4 mm) in the test quadrant. The application will be followed by gentle digital compression with a gauze sponge for 1 minute to allow polymerization and retention of the material.