Reharvested Free Gingival Grafts: 3D Shrinkage and Histological Changes

The purpose of this study is to evaluate the dimensional stability of free gingival grafts (FGG) and to investigate the relationship between graft shrinkage (GS) and the histological and biochemical characteristics of grafts reharvested from the same palatal donor site. The primary objective is to investigate the relationship between histological alterations in grafts reharvested from the same donor site and graft shrinkage at the recipient site.

This study is designed as a split-mouth study in which FGGs are applied to contralateral recipient sites within the same patient. Each participant will receive two grafts: an initial graft harvested from the palatal donor site and a second graft reharvested from the same donor site 63 days after the initial procedure.

Graft dimensional changes will be evaluated using three-dimensional digital measurements. Intraoral digital scans will be obtained at baseline, immediately after surgery, and at 1 and 3 months postoperatively. GS will be assessed through superimposition of digital models.

In addition, histological, histomorphometric, and immunohistochemical analyses will be performed on tissue samples obtained from the donor site to evaluate collagen characteristics and epithelial structure. Furthermore, protein expression levels of specific markers, including collagen type I, collagen type III, and alpha-smooth muscle actin (α-SMA), will be assessed. Early wound healing at the recipient site will be evaluated using the Landry healing index at postoperative days 7, 14, and 28. In addition, biological mediators, including transforming growth factor beta 1 (TGF-β1), vascular endothelial growth factor A (VEGF-A), and platelet-derived growth factor (PDGF), will be analyzed in wound exudate samples obtained from the recipient site to biochemically assess the early healing process.