The overall objective of this project is to evaluate, over a period of 1 year, the outcomes of either conventional free gingival graft (FGG) or mesh-FGG to increase the width of keratinized mucosa (KM) at implant sites.

The importance of the width of keratinized mucosa (KM) at implant sites remains a subject of ongoing debate. Reduced dimensions of KM (width <2 mm) are associated with mucosal recession, biofilm accumulation, soft-tissue inflammation, marginal bone loss, peri-implantitis and patient discomfort. Surgical options to increase the width of KM include an apically positioned flap, either alone or in combination with an autogenous graft or a xenogeneic collagen matrix. The free gingival graft (FGG) is a well-established technique with a history of successful clinical use. The harvesting procedure for autogenous graft from the palatal mucosa, however, is usually associated with significant patient morbidity, especially when there is a need to graft extensive mucosal areas. To overcome this problem, various graft modifications have been proposed to limit the need for large-area autografts. Examples include the accordion technique, the strip gingival autograft technique, and a vertical modification of the strip gingival graft. The expanded mesh graft, another graft modification, has been used in the field of plastic surgery, especially in the treatment of large burn wounds. Recently, De Greef, Carcuac, De Mars et al. proposed this technique to be used in periodontal plastic surgery, more specifically, in the widening of KM at implant sites by means of a meshed free gingival graft (mesh-FGG). In this case series, initially inadequate width of KM in edentulous areas could be successfully increased prior to implant installation, without the need for any extensive autograft harvesting. Data from trials comparing mesh-FGG to conventional FGG and assessing the long-term efficacy of this novel technique, however, are missing.

The investigators hypothesize that the mesh-FGG technique will demonstrate similar clinical results (non-inferiority: increase in KM width) but improved patient-reported outcomes (superiority: post-surgical morbidity) compared to the FGG.

Inclusion Criteria:

• ≥18 years of age,
• systemically healthy,
• presence of ≥2 adjacent implants in both sides of the mandibles showing <2 mm of KM on the buccal aspects,
• subjects have to present with discomfort from brushing and/or difficulties in maintaining proper home care due to inadequate dimension of KM
• Full-Mouth Plaque Score (FMPS) <20%,
• Full-Mouth Bleeding Score (FMBS) <20%.

Exclusion Criteria:

• pregnancy or lactation,
• tobacco smoking,
• uncontrolled medical condition,
• medication that can affect gingival conditions.