In vitro evaluation of topical fluorides for overdenture abutments

Topical fluorides are effective, yet none have been developed specifically for root or dentin surfaces.

This study evaluated the ability of several commercial topical fluorides to protect overdenture abutments from in vitro acid demineralization.

Twenty extracted teeth from persons aged 50 to 70 years were prepared for overdenture abutments. The teeth were sectioned to provide 40 buccal and lingual halves, covered with nail varnish except for windows on the occlusal and root surfaces, and randomly divided into 4 groups of 10 specimens, which were cycled for 6 hours in acid demineralization, washed, and then held 17 hours in a remineralizing solution for 18 days. Before each cycle, the specimens were treated with either Karigel, Karigel-N, or a NaF solution. The control group was treated with fluoride-free solution.

The depth of the artificial lesions on the root surfaces showed a statistically significant dose response. On the occlusal, there were no differences in lesion depth between the various topical fluorides and the control group. But there was a dose response when the remineralized band was subtracted from the lesion depth. Remineralization bands in the occlusal lesions were not evident in the control group, but were present in the fluoride groups.

This study suggests that higher concentrations of NaF are more protective for overdenture abutments.