Effect of xylitol varnishes on remineralization of artificial enamel caries lesions in vitro

Objectives: Analyse the effect of varnishes containing xylitol alone or combined with fluoride on the remineralization of artificial enamel caries lesions in vitro. Methods: Bovine enamel specimens were randomly allocated to 7 groups (n = 15/group). Artificial caries lesions were produced by immersion in 30 mL of lactic acid buffer containing 3 mM CaCl2 center dot 2H(2)O, 3 mM KH2PO4, 6 mu M tetraetil metil diphosphanate (pH 5.0) for 6 days. The enamel blocks were treated with the following varnishes: 10% xylitol; 20% xylitol; 10% xylitol plus F (5% NaF); 20% xylitol plus F (5% NaF); Duofluorid (TM) (6% NaF, 2.71% F + 6% CaF2), Duraphat (TM) (5% NaF, positive control) and placebo (no-F/xylitol, negative control). The varnishes were applied in a thin layer and removed after 6 h. The blocks were subjected to pH-cycles (demineralization-2 h/remineralization-22 h during 8 days) and enamel alterations were quantified by surface hardness and transversal microradiography. The percentage of surface hardness recovery (%SHR), the integrated mineral loss and lesion depth were statistically analysed by ANOVA/Tukey's test or Kruskal-Wallis/Dunn's test (p < 0.05). Results: Enamel surface remineralization was significantly increased by Duraphat (TM), 10% xylitol plus F and 20% xylitol plus F formulations, while significant subsurface mineral remineralization could be seen only for enamel treated with Duraphat (TM), Duofluorid (TM) and 20% xylitol formulations. Conclusions: 20% xylitol varnishes seem to be promising alternatives to increase remineralization of artificial caries lesions. Clinical significance: effective vehicles are desirable for caries control. Xylitol varnishes seem to be promising alternatives to increase enamel remineralization in vitro, which should be confirmed by in situ and clinical studies. (C) 2014 Elsevier Ltd. All rights reserved.