Fluoride release from a fluoride-containing amalgam in vivo

Six test subjects using a low fluoride diet collected saliva samples each morning for 1 wk to determine the normal fluoride concentration. During the following 8 wk an acrylic plate, containing amalgam “fillings” corresponding to 6 MOD amalgams in premolars, was worn each night. Saliva samples were collected every morning and analyzed with a fluoride-ion electrode. Normal fluoride values ranged from 1.22 μM to 0.57 μM. The first days after insertion of the plates the fluoride concentration ranged from 91.06 μM to 12.26 μM in the subjects. The following 25—30 days there was an exponential decline of the fluoride concentration in saliva with a half-life of 6 to 7 days. The fluoride level was significantly higher (P < 0.01) than basal levels in all subjects during this period. The following 20–25 days the fluoride level decreased more slowly, approaching the basal level. One subject had a significantly higher fluoride level for all 8 wk. Since the saliva fluoride concentrations registered seem to be sufficient to enhance remineralization, it is concluded that restorations with this material may have a favorable effect not only on secondary caries, but on any initial demineralization in the mouth.