Exchange of fluoride between bovine enamel and the surface-related cells of the oral bacterium Streptococcus mutans.
Standard areas of intact bovine enamel surface were fluoridated with dental F-varnish for 24 h and then cleaned from varnish residues and thoroughly rinsed with distilled water. Sucrose fermentation by a plaque-like layer of Streptococcus mutans cells covering such an enamel surface was accompanied by a rapid but transient accumulation of F of enamel origin by the Strep. mutans cells and by a pH drop in the plaque to pH 4.0. The uptake of F from the surface by the control cells, utilizing their carbohydrate stores and causing a smaller pH-drop, was slow but no release of F back to the cell exterior took place within 18 h. In a second experiment, F- varnished and placebo- varnished bovine enamel granules were used as above, but they were not thoroughly washed after being varnish-treated and cleaned. Both the sucrose-fermenting and the control layer of Strep. mutans rapidly released appreciable but equal amounts of fluoride from the F-treated enamel. The accumulation of F of enamel origin by the Strep. mutans cells with or without sucrose was rapid and of almost the same magnitude. In the model with the sucrose-utilizing Strep. mutans and the F-treated enamel granules, the plaque pH-drop was less and the dissolution of the enamel Ca and P completely prevented compared to the respective changes in the sucrose-utilizing model with placebo-treated enamel granules.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D003743:Dental Enamel / Q000378:metabolism*; D003773:Dental Plaque / Q000378:metabolism; D005285:Fermentation; D005460:Fluorides, Topical; D006863:Hydrogen-Ion Concentration; D010758:Phosphorus / Q000378:metabolism; D012969:Sodium Fluoride / Q000378:metabolism*; D013295:Streptococcus mutans / Q000378:metabolism*; D013395:Sucrose / Q000378:metabolism
D005460:Fluorides, Topical; C023807:sodium fluoride topical preparation; D010758:Phosphorus; D013395:Sucrose; D012969:Sodium Fluoride; D002118:Calcium