In vitro study of the effect of nanosilver fluoride on shear bond strength of orthodontic brackets and demineralization of enamel

Objective The Purpose of the present study was to evaluate the effects of nanosilver fluoride (NSF) on shear bond strength (SBS) of orthodontic brackets and prevention of enamel demineralization. Materials and methods Seventy-five human premolars divided into three group. Brackets were bonded directly to buccal surface using grengloo (Ormco) light cured orthodontic adhesive following manufacturer's instructions. In group I, no intervention was carried out. In group II, NSF was applied for 2 min before acid etching while in group III, NSF was applied for 2 min after acid etching. All samples were then subjected to pH cycle to simulate cariogenic challenge. SBS and adhesive remnant index score were evaluated for all samples then five teeth from each group were prepared for scanning electron microscopic evaluation. Results The mean SBS values were 9.74 ± 3.03, 10.39 ± 2.77, and 10.71 ± 3.34 for group I, II, and III, respectively. The one-way analysis of variance revealed nonsignificant difference among groups. For adhesive remnant index scores, statistically significant difference was found between groups I and II and groups I and III while there was no statistically significant difference between groups II and III. Scanning electron microscopic observations showed deposition of new fluoroapatite crystals with less enamel demineralization in groups II and III. Conclusion NSF could be effectively used for preventing enamel demineralization around orthodontic brackets without negatively affecting the bond strength. The site of bond failure was changed by NSF application with increased adhesive remaining on tooth surface after debonding.