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Background: Today usage of titanium implants to replace missing teeth has become a standard treatment. This also means that more individuals are more likely to suffer from peri-implantitis. During the insertion of implants, particles are released in the soft tissue, which might cause inflammation in presence of gram-negative and positive bacteria from the oral cavity.

Aim: To evaluates the effect of some oral bacteria: Porphyromonas gingivalis (Pg), Parvimonas micra (Pm), Prevotella intermedia (Pi) and Fusobacterium nucleatum (Fn) on the Ti- induced cytotoxicity and pro-inflammatory response in cultures of human macrophages.

Materials & Methods: This study involves THP-1 cells exposed to four selected bacteria in two different ratios per target cell (MOI 10 or 25). THP- 1 cells were exposed to the following 10 test-groups; Control (Co), Titanium (Ti), Pg, Pm, Pi and Fn, Pg for 24 h + Ti, Pm + Ti for 24 h or Pg, Pi and Fn for 48 h + Ti the last 24 h.Viability of the exposed macrophage cell line (THP-1 cells) was determined by neutral red uptake staining. Enzyme- Linked Immunosorbent Assay method (ELISA) for quantification of IL-1β secretion.

Results: The Titanium induced IL-1β secretion from the exposed THP-1 cells was substantially enhanced in presence of all the tested periodontitis associated bacteria. Cell viability was not affected in the presence of Ti alone nor together with the different bacteria. In opposite, viability test indicates an enhanced survival to the Ti-induced THP-1 cells in presence of bacteria.

Conclusion: All the anaerobic bacteria used in the present study increased the Ti-induced release of IL-1β from human macrophages without any significant cytotoxic effect.