In vivo study of slow-release fluoride resin and enamel uptake

The purpose of this study was to investigate in vivo enamel fluoride uptake of a slow-release boron trifluoride BIS-GMA resin material. Study subjects were orthodontic patients with at least one pair of permanent bicuspid teeth indicated for extraction. The material was applied to the buccal surface of the test tooth 1 month prior to extraction; the contralateral tooth served as the control tooth. Following extraction, the resin was removed by soaking in acetone for 36 h and polishing with a sodium bicarbonate slurry. Prior scanning electron microscopic studies have shown that this cleaning procedure effectively removes all residual resin. Enamel fluoride analyses were completed for 12 pairs of teeth from 9 subjects. The mean differences in enamel fluoride concentrations between the treated and control teeth were significantly different from zero at the 0.01 level. At each successive depth, the absolute mean amount of fluoride uptake by the test teeth was fairly constant; however, the proportional mean amount or percent increase in fluoride concentration resulting from treatment became greater in the deeper enamel layers. The data suggest that this material has the potential to provide an effective means of introducing substantial amounts of permanently bound fluoride into surface enamel, even into the deeper layers.