Action of sodium fluoride on phagocytosis by systemic polymorphonuclear leucocytes

Alterations in phagocytosis appear to be important in the onset and development of periodontitis. We investigated new substances that may be of use in the treatment of periodontitis. In a preliminary study, we tested the effect of sodium fluoride on phagocytosis by circulating polymorphonuclear leucocytes (PMNs) in 10 replicate assays using blood from six healthy subjects. Sodium fluoride was tested at concentrations of 1.0 micron to 4.0 microns against Streptococcus oralis, Streptococcus mutans, Streptococcus sobrinus and Streptococcus sanguis. The phagocytic index against all microorganisms increased significantly at all concentrations of sodium fluoride assayed; this effect was dose dependent. Sodium fluoride appeared to stimulate phagocytosis via two mechanisms: an apparent increase in bacterial susceptibility to phagocytosis, and direct stimulation of phagocytosis by PMNs.