Impact of a chronic smoking habit on the osteo-immunoinflammatory mediators in the peri-implant fluid of clinically healthy dental implants

Objective The aim of this study was to evaluate the influence of chronic cigarette smoking on the profile of osteo-immunoinflammatory markers in the peri-implant crevicular fluid (PICF) from clinically healthy implants Designs Twenty-five smokers and 23 non-smoker subjects with a unitary screwed implant-supported crown in the molar or pre-molar region were enrolled in this study. The implants should have been in functioning for at least 12 months, and the peri-implant tissue should be clinically healthy [probing depth (PD) < 4 mm with no bleeding on probing (BoP) and no evidence of radiographic bone loss beyond bone remodeling]. The levels of interferon (INF)-γ, interleukin (IL)-4, IL-17, IL-1β, IL-10, IL-6, IL-8, tumor necrosis factor (TNF)-α, matrix metalloproteinase (MMP)-2, MMP-9, osteoprotegerin (OPG), soluble receptor activator of nuclear factor-κβ ligand (RANKL), osteocalcin (OC), osteopontin (OPN), transforming growth factor (TGF)-β, and cross-linked telopeptide of type I collagen (ICTP) in the PICF were quantified by a multiplexed bead immunoassay. Results The smokers presented reduced levels of IL-4, IL-8, and TNF-α compared with the non-smoker individuals (p < 0.05). In addition, although lower OPG levels were detected in the PICF of the smokers, the RANKL/OPG ratio did not show a significant difference (p > 0.05). Moreover, higher ICTP concentrations and a higher TH1/TH2 ratio were observed in the PICF of the smoker patients (p < 0.05). No differences between the groups were observed for the other markers evaluated (p > 0.05). Conclusions Smoking habit modulate peri-implant cytokine profile, leading to reductions in IL-4, -8 TNF-α, and OPG levels and an increased ICTP and TH1/TH2 ratio in peri-implant crevicular fluid.