Abstract
Fluoride is known to have a strongly cariostatic effect, and molybdenum is thought to have a mildly cariostatic effect. (NH4)2MoO2F4, which contains both fluoride and molybdenum, has been shown to prevent dental caries and also to arrest dental caries in rat experiments. In addition, this compound did not discolor the teeth.
The purpose of this study was to investigate the mechanism of the cariostatic effect of (NH4)2MoO2F4 from the viewpoint of effects on the mineral phase of teeth. Namely, the mode of action of (NH4)2MoO2F4 with CO3-apatite, the change of its reaction products with CO3-apatite in the culture medium, and the effects of (NH4)2MoO2F4on the intact enamel were examined. The results were as follows
1) Reaction of (NH4)2MoO2F4 with CO3-apatite produced fluoridated apatite and calcium fluoride. It is considered that molybdenum substituted for the CO3-apatite component in this reaction. The carbonate content in the CO3-apatite decreased and the acid resistance of the CO3-apatite increased.
2) The reaction of (NH4)2MoO2F4 at a high concentration with CO3-apatite produced considerable calcium fluoride. It is suggested that this calcium fluoride and molybdenum detected by pretreatment of (NH4)2MoO2F4were gradually dissolved in the culture medium, and that production of fluoridated apatite and substitution of molybdenum for the apatite component took place.
3) (NH4)2MoO2F4 at high concentrations increased the acid resistance of intact enamel. Both fluoride and molybdenum penetrated into the enamel with treatment of (NH4)2MoO2F4. Calcium fluoride and molybdenum were detected in the surface zone of the enamel.
In summary, these results suggest that (NH4)2MoO2F4 gives cariostatic properties to dental minerals, especially to intact enamel.
