The aim of this randomized controlled clinical trial is to evaluate the effects of conventional free gingival graft (FGG) and modified free gingival graft (ModFGG) techniques on soft tissue thickness, volumetric change, and creeping attachment in mandibular incisors using three-dimensional direct digital analysis. The study will include a total of 34 systemically healthy, non-smoking individuals with localized Cairo Class II gingival recession. Participants will be randomly assigned to the FGG (control) and ModFGG (test) groups. Clinical measurements will be performed before surgery and at 1, 3, and 6 months post-surgery. Soft tissue thickness and volumetric changes will be analyzed three-dimensionally by overlaying digital models obtained with an intraoral scanner. Gingival recession depth, keratinized tissue height, and creeping attachment will also be assessed. The aim is to provide clinical evidence regarding the effects of the modified free gingival graft technique on soft tissue stability and volumetric gains.

Keratinized tissue deficiency and gingival recession are common mucogingival problems that may compromise periodontal health, esthetics, and patient comfort. Soft tissue grafting procedures are widely used to increase tissue thickness and volume and to achieve keratinized tissue augmentation. Among autogenous grafting techniques, free gingival grafts (FGG) are considered a predictable and reliable approach for enhancing soft tissue stability and long-term marginal tissue outcomes.

Despite their effectiveness, conventional FGG procedures may exhibit postoperative shrinkage and volume reduction due to limited vascularization at the recipient site. To overcome this limitation, a modified free gingival graft (ModFGG) technique has recently been introduced. In this technique, a connective tissue pedicle flap harvested from the apical region of the recession defect is used to cover the exposed root surface prior to placement of the free gingival graft, with the aim of improving graft vascularization and enhancing wound healing. Although previous studies have reported favorable outcomes for ModFGG in terms of root coverage, keratinized tissue gain, and patient satisfaction, available evidence is largely based on two-dimensional clinical measurements.

Conventional methods used to assess soft tissue changes, such as periodontal probing, needles, and ultrasonic devices, are either invasive or limited to linear measurements, thereby restricting the evaluation of volumetric tissue alterations. Recent advances in three-dimensional digital analysis techniques allow for reliable, non-invasive, and reproducible assessment of both linear and volumetric soft tissue changes. However, to date, no clinical study has evaluated soft tissue thickness, volumetric changes, and creeping attachment following conventional FGG and ModFGG procedures in mandibular incisors using direct three-dimensional digital analysis.

This randomized controlled clinical trial aims to compare the effects of conventional free gingival graft and modified free gingival graft techniques on soft tissue thickness, volumetric changes, and creeping attachment in mandibular incisors using a direct three-dimensional digital evaluation method. Systemically healthy, non-smoking adult patients presenting with localized Cairo Class II gingival recession will be enrolled and randomly allocated to either the FGG (control) group or the ModFGG (test) group.

Clinical and digital assessments will be performed at baseline and at 1, 3, and 6 months postoperatively. Soft tissue thickness and volumetric changes will be analyzed by superimposing digital models obtained using an intraoral scanner. Additional clinical parameters, including gingival recession depth, width of keratinized tissue, and probing depth, will also be recorded. The results of this study are expected to provide high-quality evidence regarding the effectiveness of the modified free gingival graft technique in enhancing soft tissue stability and volumetric outcomes in periodontal plastic surgery.

Inclusion Criteria:

• Age 18 years or older
• Systemically healthy individuals
• Non-smokers
• Presence of localized Cairo Class II gingival recession with a vertical recession depth of ≥3 mm on the buccal surfaces of mandibular incisors
• Probing pocket depth of ≤3 mm at the tooth/teeth to be treated
• No tooth mobility (mobility grade ≤1)
• Absence of cervical composite restorations or non-carious cervical lesions
• Presence of a shallow vestibule (<5 mm)

Exclusion Criteria:

• Pregnancy or lactation
• Untreated periodontal disease
• Presence of parafunctional habits
• Poor oral hygiene, defined as a full-mouth plaque score >20%
• Malpositioned, rotated, or crowded teeth in the buccal position
• Known systemic diseases (e.g., acquired immunodeficiency syndrome, diabetes mellitus)
• Any condition or medication that may affect gingival wound healing
• ASA physical status classification III or higher

The collected data include detailed clinical and digital intraoral scan records that may compromise participant privacy and confidentiality. In addition, informed consent for public data sharing was not obtained from participants.