Volume-Stable Collagen Matrix vs. Connective Tissue Graft for Peri-Implant Soft Tissue Defects

Peri-implant soft-tissue defects will be treated with either a volume-stable collagen matrix (VCMX; test group) or an autogenous connective tissue graft (CTG; control group) following implant placement in patients with a single missing tooth. After a mid-crestal incision and full-thickness flap elevation, the graft material will be positioned over the crest beneath the buccal flap and stabilized, followed by tension-free primary closure. Peri-implant soft-tissue thickness, echo intensity, and vascularization will be assessed non-invasively using high-resolution intraoral ultrasonography and Power Doppler imaging. Clinical periodontal parameters and patient-reported outcomes, including pain perception (visual analog scale), swelling, fatigue, analgesic consumption, and wound healing, will be recorded. These outcomes will be evaluated at baseline and on the 1st week, 1st, 3rd, and 6th months. At the 6th month, gingival biopsy samples obtained during healing abutment placement will be evaluated histologically and immunohistochemically (CD11c, CD163, COL1, COL3, MMP-1, TIMP-1) to compare the biological integration of the two graft materials.