Peri-implant Soft Tissue Augmentation Using Microneedling With i-PRF vs. Connective Tissue Graft: A Randomized Controlled Clinical Trial

Peri-implant soft tissue quality is a key determinant of implant health, long-term stability, and esthetic outcomes. Adequate peri-implant mucosal thickness and keratinized tissue width contribute to the maintenance of peri-implant health, while thin soft tissue phenotypes have been associated with increased risk of recession, discomfort during oral hygiene procedures, and peri-implant tissue complications. Connective tissue grafting (CTG) remains the gold standard for peri-implant soft tissue augmentation; however, it requires harvesting autogenous tissue from a secondary donor site, resulting in increased surgical morbidity, postoperative discomfort, and longer treatment time.

Recent regenerative approaches have focused on the use of injectable platelet-rich fibrin (i-PRF), an autologous blood-derived concentrate rich in platelets, leukocytes, fibrin, and growth factors that promote angiogenesis, collagen formation, and soft tissue healing. Microneedling is a minimally invasive technique that creates controlled micro-injuries within the soft tissues, stimulating collagen production and enhancing the penetration and biological effects of regenerative agents. Preliminary evidence suggests that combining microneedling with i-PRF may enhance peri-implant soft tissue thickness and quality while minimizing patient morbidity.

This study is designed as a prospective, parallel-arm randomized controlled clinical trial comparing microneedling combined with injectable platelet-rich fibrin (MN+i-PRF) with connective tissue grafting (CTG) for peri-implant soft tissue augmentation during implant second-stage surgery. Approximately 24 eligible participants presenting with thin peri-implant soft tissue phenotype in the esthetic zone will be randomly allocated in a 1:1 ratio to either the test or control group. Allocation concealment will be performed using computer-generated randomization and sealed opaque envelopes. Outcome assessors will be blinded to treatment allocation.

Participants in the control group will undergo peri-implant soft tissue augmentation using a subepithelial connective tissue graft harvested from the palate and stabilized at the buccal aspect of the implant site. Participants in the test group will receive microneedling using a sterile automated microneedling device followed by injection of autologous i-PRF into the peri-implant mucosa. The test intervention will be performed at implant uncovery and repeated at 2-week and 4-week follow-up visits to maximize regenerative effects.

The primary outcome measure will be the change in peri-implant mucosal thickness from baseline. Secondary outcome measures will include keratinized tissue width, peri-implant probing depth, bleeding on probing, volumetric soft tissue contour changes assessed through intraoral scanning, Pink Esthetic Score (PES), and patient-reported outcome measures including postoperative pain and treatment satisfaction. Clinical and patient-centered outcomes will be evaluated at predefined follow-up intervals extending up to 9 months after treatment.