This study aims to compare clinical outcomes and tissue stability at implant sites in the mandibular posterior region with insufficient buccal keratinized gingiva. It will assess the use of free gingival grafts either before or during the second stage of implant surgery.

To compare the clinical outcomes and the differences in hard and soft tissue stability at implant sites with insufficient buccal keratinized gingiva in the mandibular posterior region, where free gingival grafts are applied either before implant surgery or concurrently during the second stage of implant surgery.

Inclusion Criteria:

• Age ≥ 18 years, gender unrestricted;
• partially edentulous in the mandible posterior area, planned for implant-supported fixed restoration;
• Buccal keratinized mucosa width at the implant site is less than 2mm, with the transplantation area not exceeding 2 teeth;
• No soft tissue augmentation performed at the site prior to surgery;
• Overall health is good, with no systemic diseases that may affect bone metabolism or wound healing;
• Good periodontal condition, no progressive alveolar bone resorption, no periodontal abscess;
• Smoking ≤ 10 cigarettes per day.

Exclusion Criteria:

• Uncontrolled metabolic diseases;
• Severe periodontal disease, with unstable periodontal condition;
• Smoking > 10 cigarettes per day;
• Unwilling to participate in the follow-up of this study;
• Other conditions that do not meet the requirements for implant treatment.