Relative Production of IL-1β and TNFα by Mononuclear Cells After Exposure to Dental Implants

Interleukin-1 (also known as osteoclast activating factor, OAF) is a cytokine produced primarily by monocytes and macrophages and is thought to mediate many of the immunologic, metabolic, and endocrine alterations seen with microbial infection, tissue injury, inflammatory disease, and bone loss. Stimuli for IL-1 production include microorganisms, endotoxins (LPS), antigen-antibody complexes, clotting components, and other cytokines. The purpose of this study was to determine whether dental implants stimulated peripheral blood mononuclear cells (PBMCs) to produce IL-1β (OAF) as well as tumor necrosis factor (TNFα). This production may lead to bone loss or failure of an implant. Three duplicates of five different implants were incubated with 2 × 106 PBMCs/ ml in 20% autologous serum; the esterase positive PBMCs amounted to 14.5%. Measured by radioimmunoassay techniques and compared to controls, all of the implants except one caused significant in vitro generation of IL-1β and TNFα. The stimulation of IL1β/TNFα production by these materials suggests that they are not physiologically inert and that the IL-1β (OAF) production may contribute to a less favorable osseoadaptation. OAF has a physiologic (homeostatic) role in maintenance and alteration of osseous structures, but the level at which physiologic becomes pathologic is unknown. Although there were statistical differences between the cellular response to these implants, the clinical significance of the differences remains to be determined. J Periodontol 1992; 63:426-430.