Levels of peri-implant sulcular fluid levels of soluble urokinase plasminogen activator receptor and TNF-α among cigarette smokers and non-smokers with peri-implantitis

BACKGROUND: Soluble urokinase plasminogen activator receptor (suPAR) and tumor necrosis factor-alpha (TNF-alpha) are inflammatory biomarkers. No studies have yet assessed the suPAR levels in relation with TNF-alpha in the peri-implant sulcular fluid (PISF) among cigarette smokers and non-smokers with peri-implantitis. OBJECTIVE: The aim was to evaluate PISF levels of suPAR, and TNF-alpha among cigarette smokers and non-smokers with and without peri-implantitis. METHODS: Sixty male patients with peri-implantitis were included. There were 20 cigarette smokers and 20 and non-smokers with peri-implantitis (Groups 1 and 2), and 20 non-smokers without peri-implantitis (Group 3). Demographic data and information related to cigarette smoking was recorded. Peri-implant clinicoradiographic parameters (plaque index [PI], gingival index [GI], probing depth [PD] and crestal bone loss [CBL]) were assessed. The PISF samples were collected and levels of suPAR and TNF-alpha were measured. Sample-size estimation was performed and all parameters were statistically assessed. Level of significance was set at P < 0.05. RESULTS: Sixty individuals were included in Groups 1, 2 and 3 (20 in each). Peri-implant PI (P < 0.01), PD (P < 0.01) and mesial (P < 0.01) and distal (P < 0.01) CBL were significantly higher in Group 1 than in Groups 2 and 3. The PISF volume (P < 0.01) and suPAR (P < 0.01) and TNF-alpha levels (P < 0.01) were significantly higher in Groups 1 and 2 than in Group 3. There was no difference in PISF volume and suPAR and TNF-alpha levels between patients in Groups 1 and 2. In Group 2, there was a statistically significant correlation between peri-implant PD and PISF suPAR and TNF-alpha levels (P < 0.01). The suPAR and TNF-alpha levels are expressed in high concentrations in the PISF of smokers and non-smokers with peri-implantitis compared with non-smokers without peri-implantitis. CONCLUSION: In non-smokers, PISF suPAR and TNF-alpha levels are correlated with peri-implant PD.