Clinical Effects of Keratinized Mucosa Augmentation Around Dental Implant With Free Gingival Graft in Different Surgical Timing at Mandibular Posterior Sites

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.