FGG vs. collagen matrix for peri-implant keratinized tissue: autograft wins at 6 months

Around dental implants, the presence of an adequate band of keratinized tissue is widely regarded as a protective factor for long-term peri-implant health. Yet the clinical community has not reached consensus on which augmentation technique delivers the most reliable and durable soft tissue outcomes. This randomized clinical study by Engla et al. addresses that gap directly, comparing two established approaches: the free gingival graft (FGG) and a xenogenic collagen matrix (XCM).

The study enrolled patients with insufficient keratinized tissue around dental implants and randomized them to receive either FGG or XCM augmentation. Outcomes were assessed at three time points — 1, 3, and 6 months post-surgery — focusing on keratinized tissue width (KTW), soft tissue thickness (STT), probing depth (PD), and bleeding on probing (BOP). This longitudinal design allowed the investigators to track not only the magnitude of tissue gain but also its stability over time.

The results were unambiguous in favor of FGG. Patients treated with the autogenous graft showed significantly greater gains in keratinized tissue width and soft tissue thickness compared to those receiving the collagen matrix. Critically, improvements in peri-implant clinical parameters — including reduced probing depth and lower rates of bleeding on probing — were also more pronounced in the FGG group. Both interventions produced measurable improvements over baseline, confirming that XCM is not without clinical utility, but the magnitude and consistency of outcomes favored the autogenous approach at every assessed time point.

For the practicing implantologist and oral surgeon, these findings reinforce a familiar hierarchy: autogenous tissue remains the benchmark for keratinized tissue augmentation. FGG continues to deliver superior biological integration and greater volume stability, likely reflecting the inherent advantages of host-derived connective tissue and epithelium over acellular scaffold materials. The XCM, while a viable option in cases where donor site morbidity must be minimized or tissue availability is limited, should be selected with realistic expectations regarding the degree of keratinization and tissue thickness achievable.

The clinical take-home message is clear: when the primary objective is maximizing keratinized tissue width and optimizing peri-implant clinical health — particularly probing depth control and bleeding suppression — FGG should remain the first-choice technique. XCM offers a legitimate alternative but does not yet match the autogenous graft in therapeutic efficacy. Future studies with longer follow-up periods and larger sample sizes will be needed to determine whether the gap between these techniques narrows over time.