Free Gingival Grafts With or Without Xenogeneic Collagen Matrix Increase Peri-Implant Keratinised Mucosa in Reconstructed Maxillae: A 1-Year Prospective Cohort Study.

AIM: To evaluate peri-implant keratinised mucosa augmentation using free gingival grafts (FGG) versus a combined FGG/xenogeneic collagen matrix (XCM) approach in reconstructed maxillae.

MATERIALS AND

METHODS

This prospective, non-randomised cohort study included patients with vascularised bone flap reconstructed maxillae. Keratinised mucosa width (KMW) was measured pre-operatively (baseline), immediately after operation and at 1 year. The primary outcome was buccal KMW gain, which was analysed using adjusted mixed-effects models with random intercepts. Exploratory histological evaluation was performed.

RESULTS

Twenty-five patients (76 implants) were included. Baseline buccal KMW was 0.00 ± 0.00 mm (FGG) and 0.02 ± 0.15 mm (FGG/XCM). At 1 year, it increased to 4.00 ± 1.60 mm (FGG) and 2.51 ± 1.22 mm (FGG/XCM). The adjusted mean difference in buccal KMW gain was 0.84 mm (95% CI: -0.09 to 1.77 mm; p = 0.074); 97% and 93% of implants achieved palatal KMW ≥ 2 mm, respectively (adjusted p = 0.803). Vestibular depth positively predicted buccal KMW gain. Histologically, FGG sites exhibited features of orthokeratinised epithelium, whereas XCM sites resembled parakeratinised epithelium.

CONCLUSIONS

KMW increased in both approaches. Although buccal KMW gain tended to be greater with the FGG approach, the non-randomised design and potential residual confounding limit definitive comparisons.

TRIAL REGISTRATION: ChiCTR2000041104.