About this trial
This single-center prospective clinical study investigates how smoking affects palatal donor site tissue biology and, in turn, the success of connective tissue grafts used in root coverage surgery. A total of 24 systemically healthy patients with Cairo Type 1 (recession type 1 \[RT1\]) gingival recession will be enrolled: 12 smokers and 12 non-smokers. All participants will receive a coronally advanced flap combined with a subepithelial connective tissue graft (CAF + CTG) harvested from the palatal donor site.
Both donor and recipient sites will be assessed at baseline and postoperatively (2 weeks, 1 month, and 3 months) using ultra-high frequency ultrasonography (UHFUS) to measure tissue thickness, echogenicity, structural integrity, and vascularization. Residual connective tissue fragments obtained during routine graft preparation will undergo histological, histochemical, and immunohistochemical analysis (including COL1A1, COL1A2, COL3A1, α-SMA, CD31, Factor XIIIa, and IL-33). Smoking status will be biochemically confirmed via salivary cotinine enzyme-linked immunosorbent assay (ELISA). Clinical outcomes (recession depth, clinical attachment level, keratinized tissue height, percentage of root coverage) and patient-reported outcome measures (PROMs) will be compared between groups.
Primary Hypothesis: Smoking negatively affects palatal donor site biology, impairing the clinical and ultrasonographic healing outcomes of CAF + CTG procedures.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Aged 18 years or older.
Systemically healthy, with no systemic disease that could directly affect status or wound healing.
Recession classified as Cairo Type 1 (RT1 = Miller Class I and II), meaning gingival recession without interproximal attachment loss.
No previous soft tissue surgery at the surgical site.
Disqualifiers
Untreated periodontitis or peri-implantitis.
Any systemic disease that could potentially impair wound healing, such as diabetes or connective tissue disorders.
Pregnancy or breastfeeding.
Previous or concurrent use of medications affecting mucosal healing (e.g., steroids or high-dose anti-inflammatory drugs).
Trial design
Parallel
Treatments tested in this trial
Coronally Advanced Flap with Subepithelial Connective Tissue Graft (CAF + CTG)
Procedure/SurgeryAll defects are treated by a single experienced periodontist using microsurgical All defects are treated by a single experienced periodontist following the technique of Cairo et al. (2012). After local anesthesia, root surfaces are debrided, conditioned with 24% EDTA for 2 minutes, and rinsed. Vertical releasing and intrasulcular incisions are made; a full-thickness flap is raised to the mucogingival junction, then split-thickness dissection allows coronal advancement. A subepithelial connective tissue graft (0.5-1 mm) is harvested from the palate, adapted to the root surface, and secured with sutures, and the flap is positioned 1-2 mm coronal to the cemento-enamel junction.
Treatment groups
Trial outcomes
Primary outcomes
Percentage of Root Coverage
The percentage of root coverage achieved at the treated site, calculated as \[(preoperative recession depth - postoperative recession depth) / preoperative recession depth\] × 100. Recession depth is measured with a calibrated UNC-15 periodontal probe as the distance from the cemento-enamel junction to the gingival margin. This is the principal clinical measure of treatment success and allows direct comparison of graft effectiveness between smokers and non-smokers.
Secondary outcomes
Ultrasonographic Soft Tissue Thickness at the Donor and Recipient Sites
Quantitative change in soft tissue thickness measured non-invasively with ultra-high frequency ultrasonography (UHFUS), including epithelial thickness, lamina propria thickness, and total soft tissue thickness at the palatal donor site, and marginal mucosal, flap, and graft thickness at the recipient site. Measurements are standardized using custom 3D-printed surgical stents. This outcome captures tissue healing dynamics and volumetric stability over time.
Donor Site Tissue Vascularization
Quantitative assessment of blood flow and microvascularization at the palatal donor site using Color Doppler / B-Flow ultrasonography, analyzed with integrated Color Quantification software within a standardized region of interest. Vascularization is a key indicator of donor site healing capacity and is expected to be reduced in smokers.
Donor Site Histological and Immunohistochemical Tissue Profile
Characterization of the palatal donor tissue obtained from residual connective tissue fragments trimmed during routine graft preparation. This includes collagen organization and Type I/Type III collagen ratio (Picrosirius Red under polarized light), extracellular matrix organization (Masson's Trichrome), microvascular density (CD31), fibroblast/myofibroblast activity (α-SMA), matrix stabilization (Factor XIIIa), collagen expression (COL1A1, COL1A2, COL3A1), and inflammatory signaling (IL-33). This outcome defines how donor site biology differs between smokers and non-smokers.
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