Peri-implant Soft Tissue Thickness in the Aesthetic Zone: A Randomized Controlled Clinical Trial Comparing Connective Tissue Grafts and a Volume-Stable Collagen Matrix

This investigator-initiated, single-center, randomized controlled clinical trial was designed to assess the effectiveness of two different soft tissue augmentation approaches on peri-implant soft tissue thickness in the aesthetic zone. The study compared the use of an autogenous connective tissue graft (CTG) with a volume-stable collagen matrix (VCMX) in patients undergoing single-tooth implant therapy.

Eligible adult patients presenting with an indication for peri-implant soft tissue augmentation in the aesthetic zone were enrolled and randomly allocated in a 1:1 ratio to one of the two intervention groups. In the CTG group, a subepithelial connective tissue graft was harvested from the palate and placed at the peri-implant site. In the VCMX group, a commercially available volume-stable collagen matrix was used for soft tissue augmentation according to the manufacturer's instructions.

Standardized surgical and prosthetic protocols were applied in both groups. Clinical examinations and outcome assessments were performed at predefined follow-up visits. The primary outcome measure was the change in peri-implant soft tissue thickness measured at the implant site over time. Secondary outcome measures included additional clinical parameters, aesthetic outcomes, patient-reported outcomes, and the incidence of adverse events or complications.

The study protocol, patient information sheet, and informed consent form were approved by the Bioethics Committee of Wroclaw Medical University prior to study initiation. The study was conducted in compliance with Good Clinical Practice guidelines, ISO 14155, and the principles of the Declaration of Helsinki. All participants provided written informed consent before any study-related procedures were performed.