Subperiosteal tunnel assisted graft (STAG) technique: Report of two cases

Abstract Background This case report describes the clinical application of the subperiosteal tunnel‐assisted graft (STAG) technique, a novel approach for peri‐implant phenotype modification and keratinized tissue augmentation. Although free gingival grafts remain the gold standard for increasing keratinized tissue width, their effectiveness may be compromised by postoperative graft shrinkage or partial graft loss, often resulting from limited vascular supply, inadequate adaptation to the recipient bed, and insufficient graft stability—particularly in posterior regions or sites with shallow vestibules where surgical access and tension control are more challenging. Methods The STAG technique was developed to overcome these limitations through the creation of a subperiosteal tunnel that enables bilateral graft insertion and stabilization using lasso sutures at both ends of the graft. This approach facilitates simultaneous augmentation of keratinized tissue, vestibular depth, and soft tissue thickness while minimizing graft mobility and enhancing adaptation to the recipient site. Results The presented cases demonstrated successful augmentation of keratinized mucosa and vestibular depth, along with increased peri‐implant mucosal thickness and stable soft tissue integration at the treated sites. Conclusion The STAG technique may provide a predictable approach for the management of complex peri‐implant mucogingival deficiencies and peri‐implant phenotype enhancement. Key points Subperiosteal tunnel‐assisted graft (STAG) technique offers a predictable alternative to conventional free gingival grafts for peri‐implant mucosal augmentation. By maintaining close adaptation between the donor graft and recipient bed, the STAG approach enhances vascular integration and reduces the risk of graft contraction or failure. This method enables peri‐implant mucosa phenotype modification therapy, including mucosal thickness gain, keratinized mucosa gain, vestibular depth, and frenum pull elimination in a single procedure, optimizing both function and patient comfort. Plain language summary The subperiosteal tunnel‐assisted graft (STAG) technique provides a predictable and effective alternative to conventional free gingival graft by enabling superior graft adaptation between the donor tissue and recipient bed.