Clinical and Histological Evaluation of Subepithelial Connective Tissue Graft Maturation at Different Healing Timepoints, With and Without Topical Application of a Polynucleotide- and Hyaluronic Acid-Based Gel

Surgical procedures and sample collections will be performed at Instituto Kahn Odontologia (Rio de Janeiro, Brazil). Laboratory analyses will be conducted at the Histology Laboratory of the School of Dentistry of Ribeirao Preto, University of Sao Paulo (FORP-USP).

SCTG removal will be performed using the double incision technique (Harris, 2003) with a standardized 1.5 mm guide scalpel, under local anesthesia (2% lidocaine, 1:100,000 epinephrine). From each graft, a standardized fragment (3×3 mm, 1.5 mm thickness) will be collected from the distal portion and immediately fixed in 10% buffered formalin for 24-48 hours, then transferred to 70% alcohol.

Laboratory analyses will include: (1) Hematoxylin-eosin (HE) for general morphological assessment; (2) Picrosirius Red under polarized light for quantification of collagen density and proportion of type I and type III collagen fibers; (3) Immunohistochemistry for vascularization assessment, measuring microvessel density (n/mm²) and vascular area (%).

Statistical analysis will use paired Student's t-test or Wilcoxon test for paired samples, depending on data distribution (Shapiro-Wilk test), with significance level of 5% (p<0.05).