Soft Tissue Augmentation Around Dental Implants

The goal of this study is to determine which method better increases the volume of soft tissues (gums) around dental implants: using the patient's own tissues or applying collagen matrices. The study also evaluates the safety of these methods and their impact on smile aesthetics. The main questions it aims to answer: Which method provides greater and more stable increase in gum thickness around the implant? Does the choice of material affect gum color (how well it matches adjacent areas)? What features of healing and cellular tissue structure are observed when using different materials? Researchers will compare: Autogenous connective tissue grafts (CTG) - the patient's own connective tissue grafts harvested from the palate or maxillary tuberosity Xenogeneic collagen matrices (XCM) - bioresorbable materials of animal origin (Fibro-Gide® and FibroMatrix®) that do not require harvesting the patient's own tissue Participants will: Undergo a surgical procedure to increase soft tissue volume in the area of implant placement (using one of four methods assigned randomly) Attend clinic visits for follow-up examinations and assessments: * Before surgery * 3 months after surgery * 6 months after surgery Undergo additional examinations: * 3D intraoral scanning to assess changes in tissue volume * Cone-beam computed tomography (CBCT) to measure gum thickness * Polarized-light photography to evaluate gum color * Collection of a small tissue sample (biopsy) for laboratory analysis of tissue structure and cellular composition