The previous reports of both epidemiological and animal model studies demonstrated that the element molybdenum (Mo) might have some anti-caries effects. We have recently developed a new chemical agent, (NH₄)₂MoO₂F₄, containing both fluoride and molybdenum as anti-caries elements. Animal model studies revealed that the topical application of 10% (NH₄)₂MoO₂F₄ significantly reduced the dental caries in rats.
In this paper, we described the effects of (NH₄)₂MoO₂F₄ on human enamel in vitro. After topical application, the solubility of the enamel by an acid buffer was evaluated by measuring the calcium loss. In addition, the reduction of artificial caries-like lesions was investigated by means of polarizing microscopic analysis, microradiographic examination and electron microprobe analysis. To confirm the effects of this agent, NH₄F and (NH₄)₆Mo₇O₂₄.4H₂O were employed with equal concentration of fluoride or molybdenum at same pH.
Compared with two agents containing fluoride or molybdenum, (NH₄)₂MoO₂F₄was found to be most effective for protecting the enamel surface. However, (NH₄)₆Mo₇O₂₄.₄H₂O also showed a considerable effect.
These results suggest that molybdenum has an anti-caries property and increase the effect of fluoride.