The Impact of Cytokines Expression in Peri-implant Crevicular Fluid Associated with Keratinized Tissue Augmentation via Xenogeneic Collagen Matrix: A Pilot Study

The xenogeneic collagen matrix (XCM) is widely used for keratinized mucosa augmentation around natural teeth and dental implants due to its consistent efficacy and the advantage of avoiding a second surgical site. However, the shrinkage rate of XCM after surgery exceeds 50%, which is not conducive to accurate preoperative design. This study aimed to investigate factors influencing XCM shrinkage.Fifteen participants with buccal keratinized tissue width (KTW) <2 mm around mandibular single implants underwent XCM-based KTW augmentation. Clinical parameters were recorded, and peri-implant crevicular fluid (PICF) was collected preoperatively and at 3-month follow-ups. Twenty cytokines in PICF were assessed using a commercial kit, with Spearman tests evaluating correlations between cytokines, clinical parameters, and shrinkage predictors.XCM significantly increased KTW from 1.39 ± 0.26 mm to 4.13 ± 1.19 mm at 3 months (<i>p</i> < 0.001), with a shrinkage rate of 60.12 ± 12%. The PICF showed significant decreases in C-reactive protein (CRP), interleukin-6 (IL-6), calprotectin (CLP), and keratin type II cytoskeletal 1 (K2C1) (<i>p</i> < 0.05) and a significant increase in osteoprotegerin (OPG) at 3 months (<i>p</i> < 0.05). Preoperative keratinized tissue thickness (KTT) and cathepsin K (CTSK), along with K2C1 at 3 months, correlated with XCM shrinkage.KTW augmentation alters cytokine expression. Thin preoperative KTT and high CTSK in PICF may predict high postoperative XCM shrinkage.Gingival phenotype significantly impacts XCM shrinkage after augmentation. PICF cytokine expression could serve as a predictive biomarker.The Chinese Clinical Trial Registry, no. ChiCTR2500100933 (last updated on 17/04/2025).