Effect of high-fluoride dentifrice and bracket bonding composite material on enamel demineralization adjacent to orthodontic brackets in vitro

BACKGROUND: There is a lack of information about the association of high-fluoride dentrifrice and fluoride-containing bonding material to prevent enamel white spot lesions development adjacent to brackets. The aim of this in vitro study was to evaluate the effect of high-fluoride dentifrice and fluoride-containing bonding material on enamel demineralization adjacent to orthodontic brackets. MATERIAL AND METHODS: Forty-eight enamel specimens with 7x7x2 mm were obtained from bovine incisors. Orthodontic brackets were bonded with fluoride-containing resin composite (OrthoCem®) or fluoride-free low viscosity resin. The specimens were submitted to an 8-day pH cycling that consisted in the daily immersion of specimens in the demineralizing solution for 4 h and in artificial saliva for 20 h in an incubator at 37° C. The treatments consisted in 5 min-immersion between the cycles of fluoride (F) suspensions containing 275 µg F/mL, 1,250 µg F/mL or distilled water (negative control). The 275 and 1,250 µg F/mL concentrations were used to simulate salivary dilution of 1,100 and 5,000 µg F/g dentifrices during toothbrushing. After the experiment, cross-sectional hardness was performed to analyze the lesion area of the specimens. Tukey post hoc test after two-way ANOVA with p at 5% was used as statistical analysis. RESULTS: The specimens treated with high-fluoride dentifrice showed significantly less demineralization in comparison with the other treatments (p>0.05). There was a significant difference in the cross-sectional hardness values for the specimens bonded with OrthoCem when compared to the low viscosity resin (p>0,05). CONCLUSIONS: The use of high-fluoride dentifrice associated with fluoride-containing bonding material promoted a greater reduction of enamel demineralization adjacent to orthodontic brackets. Key words:Demineralization, dentifrice, fluoride, bonding materials, orthodontic brackets.