The Role of Interleukin‐8 in the Estimation of Responsiveness to Steps 1 and 2 of Periodontal Therapy

Objective To investigate the association between interleukin‐8 (IL‐8) levels in gingival crevicular fluid (GCF) and total oral fluid (TOF) and the responsiveness to steps 1 and 2 of periodontal therapy. Materials and Methods One‐hundred and fifty‐nine patients affected by periodontitis received steps 1 and 2 of periodontal therapy. At baseline, TOF and GCF samples were collected and analysed for IL‐8 (Il‐8 TOF /IL‐8 GCF ) using flow cytometry. Therapy outcomes were relative proportions of residual periodontal pockets (PPD%), pocket closure (PC) rates and pocket probing depth (PPD) reductions; these were associated with IL‐8 TOF /IL‐8 GCF . Results High IL‐8 TOF was significantly associated with higher residual PPD% ( p = 0.044) and lower PPD reduction compared to low IL‐8 TOF (high 0.79 ± 1.20 mm vs. low 1.20 ± 1.20 mm, p < 0.001) in non‐smokers, while in smokers high IL‐8 GCF was related to lower PPD reduction (high 0.62 ± 1.22 mm vs. low 0.84 ± 1.12 mm, p = 0.009). Furthermore, high baseline IL‐8 TOF was significantly associated with poorer PC rates compared to medium and low concentrations in both non‐smokers (high 41% vs. medium 55% vs. low 58%, p < 0.001) and smokers (high 34% vs. medium 44% vs. low 46%, p < 0.001). Conclusion High IL‐8 concentrations at baseline had a significant impact on residual PPD%, PC rates and PPD reduction. The findings suggest that, especially in non‐smokers, baseline IL‐8 levels collected from the TOF could serve as a component in the estimation of responsiveness to steps 1 and 2 of periodontal therapy.