Efficacy of Collagen Matrix for Peri-implant Soft Tissue Phenotype Modification

A stable band of keratinized mucosa (KM) around dental implants is thought to minimize tissue recession and provide resistance against mechanical, chemical, and microbial challenges, thereby preserving peri-implant tissue health. Soft tissue augmentation is often employed to enhance the soft tissue phenotype in such cases. While autogenous grafts such as free gingival grafts (FGG) remain the gold standard, xenogeneic collagen matrices (XCM) have emerged as promising alternatives, offering reduced patient morbidity and surgical time. This randomized controlled clinical trial aims to compare the clinical efficacy and patient-reported outcome measures (PROMs) of XCM versus FGG for soft tissue phenotype modification when performed during healing abutment connection around dental implants, with evaluations at both short-term (6 months) and long-term (1 and 2 years) intervals. Thirty participants will be recruited at Dubai Health Dental Hospital and randomly assigned to receive either XCM (test) or FGG (control) augmentation. Clinical assessments will be conducted at baseline (T0), 2 weeks (T2w), and at 1 (T1), 3 (T3), 6 (T6), 12 (T12), and 24 (T24) months post-surgery. The primary outcome is the change in KM width, measured from the mucosal margin to the mucogingival junction. Secondary outcomes include KM thickness, supracrestal tissue height, and soft tissue dimensional changes, assessed using intraoral scans (Trios 5) and superimposed STL files. Additional measurements include peri-implant soft tissue level and phenotype. PROMs will be recorded in the first postoperative week and at the 3-year mark using a visual analog scale (VAS). Clinical indices such as plaque index, bleeding index, and probing depth will be evaluated at 6 months, 1 year, and 2 years. Marginal bone level changes and implant survival rates will also be tracked throughout the study period.