Background <p>Vertical bone augmentation in the posterior mandible presents significant challenges due to anatomical constraints and frequent deficiencies in soft tissue. Optimizing the soft-tissue phenotype prior to augmentation is critical to ensure stable wound closure and to provide the vascular support necessary for successful graft integration. This article introduces the pedicled masseter-buccinator periosteal flap, a novel technique that uses highly vascularized tissue to improve the quality and quantity of soft-tissue covering while also promoting graft survival.</p> Case presentation <p>A patient presented with an edentulous site in the left mandibular molar region, exhibiting a severe combined vertical and horizontal ridge deficiency. Panoramic radiography revealed a non-restorable implant and a hopeless tooth in the premolar area, resulting in an extensive defect at this site. Following removal of the implant and tooth, a large three-dimensional ridge defect was confirmed intraoperatively. After local decontamination, a pedicled masseter-buccinator periosteal flap was dissected from the inner aspect of the cheek. A partial-thickness flap, which included limited buccinator and masseter muscle fibers along with the periosteal layer was elevated. The flap was rotated mesially and sutured to the lingual periosteum to achieve stable soft tissue augmentation. Finally, the overlying primary mucoperiosteal flap was sutured, resulting in a double-layered tissue closure. Two months later, three-dimensional ridge augmentation in the left mandibular premolar-molar region was performed using the split-bone block technique with autogenous graft harvested from the ipsilateral mandibular retromolar area. After three months, two implants were inserted in combination with a Kazanjian vestibuloplasty. After three months of healing, the implants were uncovered, allowing completion of the prosthetic rehabilitation. Radiographic follow-up at two years showed stable peri-implant bone levels and clinical examination confirmed healthy and stable soft-tissue conditions.</p> Conclusion <p>The pedicled masseter-buccinator periosteal flap demonstrated to be a reliable and effective approach for soft tissue augmentation in the posterior mandible and support vertical bone grafting. Early clinical results indicate a high level of predictability with few complications making this technique a promising option in anatomically challenging cases.</p> Graphical abstract <p></p>