Evaluation of the Effects of Injectable Platelet-Rich Fibrin and Hyaluronic Acid Treatments, Administered in Addition to Free Gingival Graft Therapy, on Clinical Healing.

Gingival recession and inadequate keratinized tissue are common mucogingival problems that can compromise periodontal health. Free gingival graft (FGG) therapy is considered the gold standard for increasing keratinized tissue; however, dimensional shrinkage of the graft during the healing process remains a significant clinical challenge. The survival and success of the graft depend heavily on rapid revascularization.

This randomized controlled clinical trial aims to investigate whether the adjunctive use of biological agents can minimize graft shrinkage and enhance soft tissue healing.

All eligible patients will initially receive non-surgical Phase 1 periodontal therapy, including professional plaque removal and oral hygiene instructions.

During the surgical phase, a partial-thickness recipient bed will be prepared in the mandibular incisor region. A free gingival graft of approximately 1 to 1.5 mm thickness will be harvested from the palatal donor site.

Depending on the randomization assignment:

In the first experimental group, the harvested FGG will be hydrated in injectable platelet-rich fibrin (i-PRF), which is obtained from the patient's own venous blood via centrifugation, prior to being sutured to the recipient bed.

In the second experimental group, the FGG will be hydrated in a 0.8% hyaluronic acid (HA) gel before fixation.

In the control group, the FGG will be applied and sutured conventionally without the use of any additional biological agents.

Following graft fixation, a periodontal dressing will be applied to protect the recipient site, and a custom surgical stent combined with a hemostatic sponge will be used to stabilize the palatal donor site. Patients will be prescribed postoperative medications (antibiotics, analgesics, and antibacterial mouthwash) and advised on a soft diet. Standardized clinical photographs and digital image analysis software will be utilized to accurately measure graft dimensional changes during the follow-up period.

• Free gingival graft (Procedure), also known as Conventional FGG: The free gingival graft is obtained from the palatal donor site (1-1.5 mm thickness) and directly applied and sutured to the recipient site without any additional biological agents.
• Free Gingival Graft with i-PRF (Procedure), also known as FGG + injectable platelet-rich fibrin: The free gingival graft is obtained from the palatal donor site (1-1.5 mm thickness) and hydrated in injectable platelet-rich fibrin (i-PRF) before fixation at the recipient site. i-PRF is prepared by centrifuging the patient's venous blood at 2500 rpm for 3 minutes.
• Free Gingival Graft with Hyaluronic Acid (Procedure), also known as FGG with 0.8% HA gel, Gingigel: The free gingival graft is obtained from the palatal donor site (1-1.5 mm thickness) and soaked in 0.8% hyaluronic acid (HA) gel before fixation at the recipient site.

Primary outcomes

• Percentage of Graft Shrinkage [Baseline, 1 month, and 3 months post-operation]: Graft shrinkage will be evaluated by calculating the surface area of the graft in square millimeters using standardized clinical photographs and ImageJ software. The percentage of shrinkage is calculated with the formula: ((Immediate post-operative graft area - Follow-up graft area ) / Immediate post-operative graft area) x 100.

Secondary outcomes

• Probing Depth (PD) [Baseline, 1 month, and 3 months post-operation]: Measurement of Probing Depth (PD) in millimeters using a UNC-15 periodontal probe.
• Wound Healing Index [7 days, 14 days, 21 days, 1 month, and 3 months post-operation]: Soft tissue healing will be assessed using the Landry, Turnbull, and Howley Index. Scores range from 1 (very poor) to 5 (excellent) based on parameters such as tissue color, bleeding on palpation, presence of granulation tissue, and incision margins.
• Root Coverage Esthetic Score (RES) [3 months post-operation]: Objective evaluation of the esthetic outcomes using the Root Coverage Esthetic Score (RES). The system evaluates five anatomical variables (gingival margin, marginal tissue contour, soft tissue texture, mucogingival junction alignment, and gingival color). The total score ranges from 0 to 10, with 10 representing a perfect esthetic outcome. Gingival Margin (GM): Scored as 0, 3, or 6 points depending on the amount of root coverage. Marginal Tissue Contour (MTC): 1 point if regular/proper, 0 points if irregular. Soft Tissue Texture (STT): 1 point if harmonious with the adjacent tissue, 0 points if not. Mucogingival Junction Alignment (MGJ): 1 point if aligned with the adjacent MGJ, 0 points if not. Gingival Color (GC): 1 point if there is a color match with the adjacent tissue, 0 points if not. The total score ranges from a minimum of 0 to a maximum of 10, where higher scores mean a better esthetic outcome.
• Clinical Attachment Level (CAL) [Baseline, 1 month, and 3 months post-operation]: Measurement of clinical attachment level in millimeters using a UNC-15 periodontal probe.
• Gingival Recession Height [Baseline, 1 month, and 3 months post-operation.]: Measurement of gingival recession height in millimeters using a UNC-15 periodontal probe.
• Keratinized Tissue Height [Baseline, 1 month, and 3 months post-operation.]: Measurement of keratinized tissue height in millimeters using a UNC-15 periodontal probe.
• Keratinized Tissue Thickness [Baseline and 3 months post-operation.]: Keratinized tissue thickness was measured using a size 25 endodontic spreader equipped with a silicone stopper. Following tissue penetration, the distance from the tip of the spreader to the stopper was measured using a digital electronic caliper in millimeters.

Other outcomes

• Postoperative Pain [Up to 7 days post-operation]: Postoperative pain intensity will be evaluated daily by the patients using a 10 cm Visual Analogue Scale (VAS), where 0 indicates no pain and 10 indicates the worst imaginable pain.
• Patient-Reported Comfort Level: Postoperative Bleeding [Up to 14 days post-operation]: Patient-reported comfort levels regarding postoperative bleeding will be assessed daily using a 5-point Likert scale. The scale ranges from 1 to 5 (1 = Very dissatisfied, 5 = Very satisfied), where higher scores indicate greater aesthetic satisfaction. minimum 1 to a maximum of 5, where higher scores mean a better outcome.
• Patient-Reported Comfort Level: Postoperative Edema [Up to 14 days post-operation]: Patient-reported comfort levels regarding postoperative edema will be assessed daily using a 5-point Likert scale. The scale ranges from 1 to 5 (1 = Very dissatisfied, 5 = Very satisfied), where higher scores indicate greater aesthetic satisfaction. minimum 1 to a maximum of 5, where higher scores mean a better outcome.
• Patient-Reported Comfort Level: Difficulty Speaking [Up to 14 days post-operation]: Patient-reported comfort level regarding difficulty speaking will be assessed daily using a 5-point Likert scale. The score ranges from a minimum of 1 to a maximum of 5 (1 = Very dissatisfied/Severe discomfort, 5 = Very satisfied/No discomfort), where higher scores mean a better outcome (greater patient comfort).
• Patient-Reported Comfort Level: Difficulty Eating [Up to 14 days post-operation]: Patient-reported comfort level regarding difficulty eating will be assessed daily using a 5-point Likert scale. The score ranges from a minimum of 1 to a maximum of 5 (1 = Very dissatisfied/Severe discomfort, 5 = Very satisfied/No discomfort), where higher scores mean a better outcome (greater patient comfort). minimum 1 to a maximum of 5, where higher scores mean a better outcome

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Individuals aged 18 years or older.
* Systemically healthy patients with no contraindications for periodontal surgery.
* Patients presenting with gingival recession and/or inadequate width of keratinized tissue requiring Free Gingival Graft (FGG) therapy.
* Non-smokers.
* Patients who provide written informed consent to participate in the study.

Exclusion Criteria:

* Patients with systemic diseases that may affect wound healing (e.g., uncontrolled diabetes mellitus, autoimmune disorders).
* Pregnant or lactating individuals.
* Patients with poor oral hygiene.
* Current smokers or tobacco users.
* Patients who have received periodontal surgery in the designated surgical area within the last 6 months.

• Gülbahar USTAOĞLU, Professor, Principal investigator, University of Health Sciences, Gülhane Faculty of Dentistry