Clinical outcomes of free gingival graft, xenogeneic collagen matrix, and acellular dermal matrix for peri-implant keratinized mucosa augmentation: a randomized controlled trial.

چکیده اصلی

OBJECTIVES: To evaluate the effects of autologous free gingival graft (FGG), xenogeneic collagen matrix (XCM), and acellular dermal matrix (ADM) combined with apically positioned flap (APF) on buccal soft-tissue volume change and keratinized mucosa augmentation around dental implants. MATERIALS AND METHODS: Forty-four implants with buccal keratinized mucosa width (KMW) < 2 mm were randomly allocated to the FGG group, XCM group, or ADM group. The primary outcome was buccal soft-tissue volume change over a 12-month follow-up. Secondary outcomes included KMW, KMW shrinkage rate, mucosa thickness (MT), and peri-implant soft tissue health. Esthetic outcomes, postoperative pain, and patient satisfaction were further evaluated. RESULTS: Net buccal soft-tissue volume change decreased over time in all groups but remained significantly greater in the FGG group throughout follow-up. At 12 months, model-estimated net volume changes were 24.10 mm³ (95% CI: 2.69, 45.51) for FGG, 3.34 mm³ (- 19.77, 26.45) for XCM, and - 17.34 mm³ (- 40.45, 5.77) for ADM (P = 0.041), with FGG significantly exceeding ADM after Bonferroni adjustment. KMW decreased progressively in all groups, with no significant between-group differences at any time point. At 12 months, observed KMW was 2.93 ± 1.29 mm (FGG), 2.52 ± 0.51 mm (XCM), and 1.86 ± 0.82 mm (ADM). Using the immediately postoperative KMW as the reference, the 12-month KMW shrinkage rates were 56.25%, 61.44%, and 74.07%, respectively. FGG showed significantly greater mucosal thickness gain than ADM at 6 and 12 months (P < 0.05), while XCM did not differ significantly from either group. Esthetic outcomes, peri-implant parameters, patient satisfaction, and postoperative pain were comparable among groups (P > 0.05). CONCLUSIONS: FGG plus APF provided the most favorable maintenance of peri-implant buccal soft-tissue volume and thickness over 12 months. XCM showed intermediate performance, whereas ADM showed the greatest dimensional reduction. All three grafts showed stable peri-implant clinical parameters over 12 months, achieved acceptable esthetic outcomes, and yielded high patient satisfaction. CLINICAL RELEVANCE: For peri-implant soft-tissue augmentation with APF, FGG showed better maintenance of buccal soft-tissue volume and thickness than ADM over 12 months, while XCM showed intermediate performance. Graft selection should therefore consider the expected need for long-term dimensional stability. TRIAL REGISTRATION: This trial was registered in the Chinese Clinical Trial Registry with the registration number ChiCTR2100041688 ( https://www.chictr.org.cn/showproj.html?proj=66722 ) on January 1, 2021.

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