Which gum graft technique wins for implant health?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Men or women aged 18 years or older who voluntarily agree to sign the informed consent form before any study-related procedure is performed. * Single or multiple edentulous spaces (≤3 units) located in the posterior maxilla or mandible, presenting osseointegrated implants in first-stage surgery with a -healing period of more than 8 weeks. * ASA classification I or II. * Periodontal and peri-implant health. * O'Leary plaque index ≤15%. * Keratinized mucosa width ≤2 mm and/or vestibular depth \<4 mm at at least one site. * Commitment to attend all follow-up visits over 6 months. Exclusion Criteria: * Systemic diseases that may interfere with performing FGG (free gingival graft), including but not limited to: poorly controlled diabetes mellitus (HbA1c \> 8% or per clinical judgment), immunodeficiencies or immunosuppressive treatment, uncontrolled hematological diseases or coagulation disorders, anticoagulant or antiplatelet treatment that cannot be adjusted according to standard clinical practice, active neoplasms under treatment, severe renal or hepatic insufficiency, decompensated cardiovascular diseases, and any other medical condition that, in the investigator's judgment, could compromise participant safety or proper tissue healing. * Any contraindication to oral surgical procedures. * Periodontal and peri-implant health as defined by the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. * Patients who smoke tobacco or equivalent products, as well as former smokers with an abstinence period ≤12 months. * History of substance abuse (drugs or alcohol) or any other factor (e.g., severe psychiatric illness) that, in the investigator's opinion, could interfere with the patient's ability to cooperate and comply with the study. * Patients who have participated in a clinical trial within the last 30 days. * Pregnant or breastfeeding women.