Dimensional and Colorimetric Changes of Keratinized Tissue following Free Gingival Grafts Around Teeth: A Prospective Clinical Study

Objectives : To assess the three-dimensional and colorimetric changes of keratinized tissue following free gingival grafting to widen the band of keratinized gingiva over a one-year follow-up period. Material & Methods: 20 subjects with insufficient keratinized tissue width (KTW<2 mm) underwent FGG procedures. Intraoral scans were obtained at baseline, immediately after surgery, and at 6 weeks and 3, 6, and 12 months. Linear and volumetric changes were assessed through the superimposition of standard tessellation language (STL) files. Gingival color was evaluated using spectrophotometry, and color differences (ΔE values) were calculated. Patient-reported outcomes were recorded to assess perceptions of the procedure. Results : Graft volume decreased by 39.3% at 6 weeks (p < 0.001), primarily due to vertical shrinkage (28.3%). All dimensional parameters decreased reaching stability at 6 weeks. Greater volumetric loss was significantly associated with wider baseline KTW (95%CI: -43.0 to -2.52, p =0.027) and a greater clinical attachment level (95%CI: -10.2 to -0.44, p=0.033). While KTW increased significantly from baseline to immediately after surgery, it decreased by 23.9% at 6 weeks (mean difference = 1.33 ± 1.13 mm, p < 0.001) and remained stable through 12 months. Color differences (ΔE) between the graft and adjacent tissue remained above the perceptibility threshold in nearly all cases throughout follow-up; however, improved color match was associated with greater initial root coverage. Patient-reported outcomes indicated low pain (VAS 3.8 ± 2.3) and high satisfaction (VAS 8.7 ± 1.2) at 12 months. Conclusions : Keratinized tissue undergoes significant dimensional alterations following FGG; however, color mismatch does not interfere with patient satisfaction (Clinical trials.gov Identifier: NCT05729919). Clinical Relevance: Free gingival grafts used to augment keratinized tissue around teeth undergo significant dimensional and colorimetric changes. Anticipating graft shrinkage and potential color differences is essential for optimal graft placement and predictable clinical outcomes.