Suppression of Streptococcus mutans in the mouths of humans by a dental prophylaxis and topically-applied iodine.

A prophylaxis followed by three topical applications of an iodine-potassium iodide solution significantly reduced the levels of Streptococcus mutans in fissure and approximal plaques and in saliva. Reductions persisted 20--24 weeks after treatment in salivary and approximal samples. A prophylaxis alone exerted a small and temporary reduction of S. mutans in occlusal fissure plaque, but did not reduce the levels of this organism in approximal plaque or in saliva. A significant relationship existed between the levels of S. mutans in saliva and the proportions of this organism in plaque. The dorsum of the tongue does not appear to constitute a significant reservoir for S. mutans following disinfecting procedures.