Effect of topical application of fluoride gel on artificial secondary caries inhibition

Purpose: To evaluate the effect of topical application of fluoride gel on artificial secondary caries around adhesive restorations. Materials and Methods: Two box-shaped cavities were prepared on both buccal and lingual dentin surfaces of bovine roots. Each cavity was restored with either a non fluoride-releasing adhesive, Clearfil SE Bond/a resin composite, Clearfil AP-X (AP-X), or an experimental fluoride-releasing adhesive, ABF/AP-X. Acidulated phosphate fluoride gel (pH 4.2) was topically applied to the restorations and cavity margins for 0 (not applying fluoride at all), 1, 2 and 4 minutes, immediately before immersion in a decalcifying solution (pH 4.5). Longitudinal sections were then cut in half through each restoration. Depths of outer lesion and thickness of inhibition zone around restorations were determined by a confocal laser scanning microscope. The data were analyzed by oneand two-way ANOVA and Fisher’s PLSD test (p<0.05). Results: Inhibition zone was observed only in ABF/AP-X with and without topical application of fluoride gel. Topical applications of fluoride for 2 and 4 minutes significantly decreased the depth of outer lesion in both restoration systems (p<0.05). Conclusion: Inhibition zone formation was observed in ABF, while it was not observed in Clearfil SE Bond. Topical application of acidulated phosphate fluoride gel for over 2 minutes was effective to decrease the depth of the outer lesion in both adhesive systems. (Int Chin J Dent 2003; 3: 53-61.)