This study is designed to evaluate a new method to improve healing in patients with gum disease (periodontitis). A total of 42 adults with gum pockets deeper than 5 millimeters will take part. All patients will undergo flap surgery, which is a standard treatment for gum disease. Half of the patients will also receive an additional treatment with injectable platelet-rich fibrin (i-PRF), made from their own blood, together with root surface cleaning using EDTA gel. Patients will be followed for 6 months. The study will measure changes in gum pocket depth, gum attachment to teeth, and healing.

Periodontitis is a chronic inflammatory disease of the tooth-supporting tissues. Open flap debridement (OFD) is a standard surgical approach for the management of deep periodontal pockets. Injectable platelet-rich fibrin (i-PRF) is an autologous, anticoagulant-free platelet concentrate prepared with low-speed centrifugation and characterized by a fibrin network that gradually releases growth factors. Neutral-pH 24% EDTA root-surface conditioning is used to remove the smear layer and expose collagen, which may support early cell attachment and the adsorption of bioactive molecules.

This single-center, randomized, parallel-group, open-label clinical trial is designed to evaluate whether the adjunctive use of i-PRF after EDTA root conditioning provides additional benefits compared with EDTA conditioning alone. Adults with periodontitis will be enrolled at a university periodontal clinic and randomized to one of two groups:

Control group: OFD with 24% EDTA gel conditioning (3 minutes)

Test group: OFD with 24% EDTA gel conditioning (3 minutes) followed by application of i-PRF retained on defect surfaces for 5 minutes

A mixed defect model (sites with both intrabony and horizontal components) will be included to reflect real-world clinical presentations.

All participants will receive standardized Phase I therapy before surgery. On the day of surgery, an antiseptic rinse will be performed, local anesthesia will be administered, full-thickness flaps will be elevated, and meticulous debridement/root planing will be completed. In the test arm, i-PRF will be prepared from venous blood collected into plain glass tubes and centrifuged at ~700 rpm (60 g) for 3 minutes; the platelet-rich upper layer (~1-1.5 mL per tube) will be aspirated and applied to the defect for 5 minutes before primary closure with 4-0 monofilament sutures. Postoperative care will include analgesic and/or anti-inflammatory medication as needed and an antiseptic mouthwash; systemic antibiotics will not be routinely prescribed. Sutures will be removed at approximately 1 week. A planned follow-up schedule will include weekly visits during the first month and monthly visits thereafter through month 6.

The primary outcome will be the change in probing pocket depth (PPD) at surgical sites at 6 months. Key secondary outcomes will include clinical attachment level (CAL), plaque and gingival indices, bleeding on probing, gingival recession depth and width, patient-reported pain and sensitivity (VAS), and postoperative clinical healing parameters such as edema, erythema, and necrosis, assessed at prespecified time points. Randomization will be computer-generated; surgeries and measurements will be performed by an experienced periodontist using calibrated probes.

The study has been approved by an institutional ethics committee and will be conducted in accordance with the Declaration of Helsinki and good clinical practice principles. The trial does not involve any U.S. FDA-regulated drug or device. An independent data monitoring committee will not be convened given the low-risk, single-center nature of the interventions; adverse events will be actively assessed at follow-up visits, and participants may withdraw at any time without penalty.

Inclusion Criteria:

• Adults aged 18 years and older
• Diagnosis of Stage II-IV periodontitis
• Presence of ≥3 adjacent teeth with probing pocket depth (PPD) ≥5 mm
• Systemically healthy individuals
• Non-smokers
• Ability and willingness to comply with oral hygiene instructions and study follow-up visits

Exclusion Criteria:

• Systemic diseases or conditions affecting periodontal healing (e.g., uncontrolled diabetes, immunodeficiency)
• Pregnancy or lactation
• Current or previous smokers
• Use of medications that may affect periodontal status (e.g., immunosuppressants, bisphosphonates)
• Previous periodontal treatment within the last 6 months

Individual participant data (IPD) will not be shared due to patient privacy considerations and institutional restrictions.

Participants were blinded to group allocation; however, investigators and outcome assessors were not blinded due to the surgical nature of the interventions.