Comparison of root coverage by injectable-platelet rich fibrin in thick and thin phenotypes: a parallel-armed, prospective, preliminary clinical study with up to 48 months of follow-up.

OBJECTIVE

This study aimed to compare the effectiveness of injectable platelet-rich fibrin (I-PRF) using a submucosal injection technique for creeping attachment in thin and thick phenotypes with gingival recession.

METHODOLOGY: The study was designed as a prospective clinical trial. Participants were divided into two groups based on gingival thickness (GT): thin phenotype group (≤1.0 mm) and thick phenotype group (>1.0 mm). I-PRF was applied once a month to each gingival site using the submucosal injection technique, for a total of three applications. Periodontal parameters were measured at baseline (T0), nine months after treatment (T1), and 12-48 months after treatment (T2). Root coverage percentage (RC%) was calculated.

RESULTS

Twelve systemically healthy, non-smoking patients (seven males and five females; mean age: 36.5±9.4), comprising 66 teeth, were analyzed. The primary outcome, RC%, demonstrated a statistically significant intergroup difference at T1 (p=0.032); however, this difference was not statistically significant at T2. In the thick phenotype group, RC% was 20.91±30.80% in T1 and increased to 31.40±30.92% in T2 (p=0.040). Conversely, the thin phenotype group showed higher RC% values at T1 (35.04±29.76%), which were not sustained at T2 (30.70±28.46%; p=0.355). Recession depth decreased in both groups at all time points, but this difference was not statistically significant. Keratinized tissue width showed a significant increase in both groups, from 2.34±1.08 and 2.73±0.95 at T0, respectively, to 2.89±1.17 and 3.28±1.12 at T1 (p<0.05). In the intergroup comparison, GT values were significantly higher in the thick phenotype group than in the thin phenotype group at T0 and T2, while no significant difference was observed at T1.

CONCLUSION

I-PRF application was shown to enhance RC% in both phenotypes. A significant increase in GT was observed in the thin phenotype; however, these increases in GT and RC% were not fully sustained during long-term follow-up in this sample.Clinical Trial registration: NCT05591326.