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

Shigemitsu Toba, DDS,(a) Patricia N. R. Pereira, DDS, PhD,(b) Toru Nikaido, DDS, PhD,(a) and Junji Tagami, DDS, PhD(a)

(a)Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan, and (b)Department of Operative Dentistry, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA

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 one- and 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.)
Clinical Significance: Application of a fluoride-releasing dentin bonding system and a fluoride gel may be clinically beneficial for root caries prevention.
Key Words: dentin bonding system, fluoride gel, fluoride-release, secondary caries inhibition.