Population (P) Adult patients aged 18 years or older undergo single-tooth implant therapy in the maxilla or mandible who present with a peri-implant soft-tissue deficiency, defined as a thin soft-tissue phenotype, reduced peri-implant mucosal thickness, or inadequate buccal soft-tissue volume, and who therefore require surgical peri-implant soft-tissue augmentation
Intervention (I) Peri-implant soft-tissue augmentation performed using a xenogeneic collagen matrix, including volume-stable collagen matrices, or other porcine-derived collagen matrices, applied simultaneously with implant placement (immediate or early), at delayed implant placement, or at the time of abutment connection
Comparison (C) Peri-implant soft-tissue augmentation using an autogenous subepithelial connective tissue grafts harvested from the palate or maxillary tuberosity
Outcomes (O) Primary outcome: marginal bone loss.
Secondary outcomes: mid-buccal recession, soft tissue thickness gain, pink aesthetic score
Study design (S) Randomized controlled trials, cross sectional studies, clinical trials, cohort studies