The effect of the injectable platelet-rich fibrin on peri-implant soft tissue phenotype: a preliminary, prospective, 12-month follow-up clinical study

The aim of this study was to assess the effectiveness of submucosal injectable platelet-rich fibrin(i-PRF) application on the peri-implant soft tissue phenotype and pink esthetic outcomes in thin and thick phenotypes. The present study comprised 36 implants from 10 patients. Based on the probe visibility method, implants were classified into Group I (thin phenotype) or Group II (thick phenotype). i-PRF applications were performed three times at one-month intervals into the peri-implant keratinized submucosal and mucogingival junction region. Keratinized mucosal width (KMW), mucosal thickness (MT), and marginal soft tissue recession height (REC-H) and width (REC-W) were measured at baseline (T0), 1 (T1), 3(T3), 6 (T6), and 12 months (T12). Modified plaque index (mPI), modified gingival index (mGI), probing depth (PD), and pink esthetic score (PES) were recorded at T0 and T12. Statistical analyses were conducted utilizing Generalized Estimating Equations (GEE) in conjunction with Type III Wald Chi-square tests. Intragroup evaluations revealed that PD ​​increased significantly between T0 and T12 in Group I (p = 0.02). Intra-group and inter-group post hoc analyses demonstrated that Group I exhibited statistically significant alterations in MT at all evaluated time points, with the exception of the interval between T6 and T12 (p < 0.05). In contrast, no statistically significant changes were observed in either MT or KTW in Group II (p > 0.05). Furthermore, significant intergroup differences in MT were identified at T0, T1, and T3 (p < 0.001, p < 0.001, and p = 0.005, respectively). Evaluation of the PES across all implants revealed statistically significant enhancements in the total PES, as well as in the soft-tissue colour and contour subcomponents (p = 0.00, p = 0.04, and p = 0.04, respectively). Multiple applications of peri-implant i-PRF may alter the mucosal phenotype, particularly in thin phenotype cases, and consequently may lead to changes in the pink aesthetic score. Further research with larger samples is required. Multiple i-PRF injections applied to peri-implant sites may modify the particularly thin phenotype and may offer a new approach for clinical applications in limited cases.