Proinflammatory cytokines in the crevicular fluid of patients with peri-implantitis

The aim of this study was to review the proinflammatory cytokine profiles in the peri-implant crevicular fluid (PICF) of patients with peri-implantitis (PI). Databases were explored from 1994 up to and including July 2010 using various combinations of the following keywords: " cytokine" , " crevicular fluid" , " implant" , " inflammation" , " peri-implantitis" and " periodontitis" The eligibility criteria included: (1) original research articles; (2) clinical and experimental studies; (3) use of control group; (4) reference list of pertinent original and review studies; (5) use of statistical methods; (6) intervention: patients with and without PI; and (7) articles published only in English-language. Fifteen studies (14 case-controls and one case-report) were included. Four studies showed high levels of interleukin (IL)-1 beta (β) in the PICF of implants affected by PI (test) compared to healthy (control) sites. Two studies showed an over-expression of IL-6 and IL-8 in the PICF of implants affected by PI compared to healthy implants. One study showed an increased secretion of IL-6, IL-8 and matrix metalloproteinase-1 by fibroblastic cells cultured from test- compared to control sites. Six studies reported high levels of tumor necrosis factor-alpha (TNF-α) levels in the PICF from test-sites (sites with PI) compared to the control sites. Two studies reported a positive association between polymorphism of IL-1 gene and PI. One study showed a negative association between polymorphism of TNF-α and an increased risk of PI. Raised levels of proinflammatory cytokines are exhibited in the PICF of patients with PI.