Comparison of Three Topical Fluorides Using Computer Imaging

The purpose of this in vitro study was to evaluate the short and long-term effectiveness of fluoride var-nish and compare it with the two most commonly used topical fluorides, i.e., fluoride gel and foam. A second purpose of the study was to compare the effectiveness of these preparations on primary and permanent teeth. Enamel slabs with a thickness of 500 microns were obtained from caries free primary molars and premolars. They were divided into four groups: control, foam (F), gel (G) and varnish (V). Fluorides were applied to the enamel slabs according to the manufacturer’s instructions and were placed in a 5.1 pH acidic gel for one week. The amount of demineralization from the enamel was mea-sured by calculating the amount of light reflected from these surfaces. This was done by using a Charged Couple Device attached to a high resolution microscope with image processing software, Optima 5.22. The enamel slabs were placed in a freshly prepared acidic gel for a second week without application of fluorides. This was done to mimic a situation where fluoride is eventually brushed away from teeth. Reflective images were recorded under the previously described conditions. A two-way analysis of covariance was used to compare the treatments. The results showed no statistically signifi-cant difference (with Bonferroni correction) in the effectiveness of different fluoride preparations over the short-term (Week I comparison; p-values: F vs. G 0.079, F vs. V 0.030, G vs. V 0.44). However, the long-term protection provided by fluoride varnish was far more than fluoride gel and foam (Week II comparison; p-values: F vs. G 9X10-5 , F vs. V 7X10-8, G vs. V 1X10-4). Fluorides were equally effec-tive for both primary and permanent enamels (p-value 0.24). The results of this study suggest that flu-oride varnish is beneficial for use with white spot lesions, newly erupted permanent teeth and early decalcification in primary dentition.

1. Fluoride foam and gel and varnishes were equally efficacious in the short-term at pre-venting enamel demineralization.

2. In the longer term, fluoride varnish provided more protection against demineralization.

3. There was no difference in the effectiveness of fluorides in preventing demineralization of either primary or permanent enamel.