This randomized controlled clinical trial evaluated volumetric changes at recipient and donor sites following free gingival graft (FGG) surgery, comparing two different palatal donor regions. Forty systemically healthy non-smoking adults aged 20-40 years with Miller Class I gingival recession defects at the mandibular anterior teeth (teeth 31, 32, 41, and 42) were randomly allocated using a sealed envelope method into two groups based on the donor site: (1) the anterior palatal region (from the distal of the canine to the first molar), and (2) the posterior palatal/tuberosity region (between the first molar and the tuberosity). All grafts were harvested targeting a standardized size of 8x10 mm (80 mm²). Digital intraoral scans (3Shape TRIOS 5) were obtained preoperatively and at 1, 3, and 6 months postoperatively. Volumetric changes at both recipient and donor sites were measured using STL-based superimposition in Exocad software. The aim was to compare time-dependent volumetric change patterns at both the recipient and donor sites between the two donor groups.
BACKGROUND: Free gingival graft (FGG) is a well-established procedure to augment keratinized tissue width and manage gingival recession defects. Despite widespread clinical use, comparative data on volumetric outcomes from different palatal donor sites remain limited, and most existing studies rely on one-dimensional clinical measurements rather than volumetric analysis. Emerging evidence suggests that donor tissue composition may differ between anterior palatal and posterior palatal/tuberosity regions, potentially influencing graft behavior at the recipient site. STUDY DESIGN: Single-center, parallel-group, randomized controlled clinical trial with 1:1 allocation via sealed envelope randomization. INTERVENTION: All surgical procedures were performed by a single operator under local infiltration anesthesia (Ultracain DS, epinephrine 1:200,000). At the recipient site, a split-thickness recipient bed was prepared and the autogenous free gingival graft was stabilized using five 7-0 polypropylene monofilament sutures. Sutures were removed between days 10-14. At the donor site, no sutures were placed and the wound was left to heal by secondary intention. Grafts were harvested aiming for 8x10 mm dimensions. OUTCOME ASSESSMENT: Intraoral scans were acquired at T0 (preoperative baseline), T1 (1 month), T2 (3 months), and T3 (6 months) using a 3Shape TRIOS 5 intraoral scanner and saved as STL files. STL files were superimposed in Exocad using automatic alignment algorithms. Recipient and donor regions of interest were isolated. MeshMixer was used for STL preparation, while final volumetric calculations were performed in Exocad and recorded in mm³. To account for unavoidable minor variations in graft dimensions, volumetric data were mathematically normalized to a theoretical standard graft surface area of 80 mm² (8x10 mm). STATISTICAL ANALYSIS: Sample size was calculated a priori using G\*Power 3.1 (α=0.05, power=0.80, effect size=0.68), yielding 20 patients per group (40 total). Analyses were conducted in SPSS v22.0 with significance set at p\<0.05. Data distribution was assessed using the Shapiro-Wilk test. Within-group time effects were evaluated using Repeated Measures ANOVA; between-group comparisons at each time point were performed using independent samples t-test. Time × donor-site interaction was analyzed to determine whether volumetric change patterns differed between groups over time.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
40
Free gingival graft (FGG) surgery was performed under local infiltration anesthesia (Ultracain DS, epinephrine 1:200,000) by a single experienced operator. At the recipient site, a split-thickness recipient bed was prepared at the buccal aspect of mandibular anterior teeth presenting Miller Class I gingival recession. The autogenous free gingival graft was harvested from the anterior palatal region, defined as the area between the distal aspect of the maxillary canine and the first molar, targeting dimensions of 8 × 10 mm. The graft was secured at the recipient site using five 7-0 polypropylene monofilament sutures. No sutures were placed at the donor site; the wound was left to heal by secondary intention. Sutures at the recipient site were removed between postoperative days 10 and 14. All patients received standardized postoperative instructions and analgesic recommendations.
Free gingival graft (FGG) surgery was performed under local infiltration anesthesia (Ultracain DS, epinephrine 1:200,000) by a single experienced operator. At the recipient site, a split-thickness recipient bed was prepared at the buccal aspect of mandibular anterior teeth presenting Miller Class I gingival recession. The autogenous free gingival graft was harvested from the maxillary tuberosity / posterior palatal region, targeting dimensions of 8 × 10 mm. The graft was secured at the recipient site using five 7-0 polypropylene monofilament sutures. No sutures were placed at the donor site; the wound was left to heal by secondary intention. Sutures at the recipient site were removed between postoperative days 10 and 14. All patients received standardized postoperative instructions and analgesic recommendations.
Ondokuz Mayis University, Faculty of Dentistry, Department of Periodontology
Samsun, Samsun, Turkey (Türkiye)
Volumetric change at the recipient site
Standardized volumetric change (mm³) at the recipient site compared with preoperative baseline (T0), measured via three-dimensional STL-based superimposition of intraoral scans (3Shape TRIOS 5) using Exocad software. Volumetric data were mathematically normalized to a theoretical standard graft surface area of 80 mm² (8x10 mm) to account for minor graft size variations. Negative values indicate volume loss; positive values indicate volume gain relative to baseline.
Time frame: 1, 3, and 6 months postoperatively
Volumetric change at the donor site
Standardized volumetric change (mm³) at the palatal donor site (either anterior palatal or posterior palatal/tuberosity, as per group allocation) compared with preoperative baseline (T0), measured via three-dimensional STL-based superimposition of intraoral scans (3Shape TRIOS 5) using Exocad software. Negative values indicate volume loss relative to baseline; positive values indicate volume gain relative to baseline.
Time frame: 1, 3, and 6 months postoperatively
Time × donor-site interaction effect on volumetric change at the recipient site
Repeated Measures ANOVA interaction term evaluating whether time-dependent volumetric change patterns at the recipient site differ between the two donor groups (anterior palatal versus posterior palatal/tuberosity). A significant interaction (p\<0.05) indicates that volumetric change trajectories across time differ between donor groups.
Time frame: Across 1, 3, and 6 months postoperatively
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