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.