Augmentation of Peri-implant Keratinized Mucosa Using a Combination of Free Gingival Graft Strip with Xenogeneic Collagen Matrix or Free Gingival Graft Alone: A Randomized Controlled Study

Purpose: To evaluate the gain in peri-implant keratinized mucosa (KM) using a combination of a free gingival graft (FGG) strip with a xenogeneic collagen matrix (XCM) and compare it to that of an FGG alone. Materials and Methods: This randomized controlled clinical study included a total of 30 patients with a minimal amount of peri-implant KM (≤ 1 mm) in the maxillary and mandibular anterior regions (including the premolars). The study population was divided into two groups using a randomization protocol; group A (n = 15) received a combination of FGG strip and XCM, and group B (n = 15) received FGG only to augment the KM. Clinical parameters included width of KM (WKM) measured at baseline, 1 month, and 6 months; a customized pink esthetic score (PES) measured at baseline and 6 months; and patient morbidity using visual analog scale (VAS) at days 1, 7, and 14 postoperatively. Results: After 1 month, both groups showed statistically significant gain in KM that reduced slightly by the 6-month follow-up but remained statistically significant when compared to baseline. When the gain was compared between the two groups, the difference was not statistically significant. Better esthetic outcomes and lower morbidity were reported in group A compared to group B, and this difference was statistically significant. Conclusions: Within the limitations of the study, it can be concluded that the combination of FGG strip with XCM is a viable alternative to the use of FGG in augmenting peri-implant KM.