Purpose: To evaluate the effectiveness of Vanish XT in preventing white spot lesions (WSLs) when placed around orthodontic brackets. The efficacy of Vanish XT was compared with that of Pro Seal, a commercially available product already proven in preventing demineralization. Materials and Methods: Sixty extracted human canine teeth were divided into three groups (n = 20). The two experimental groups were treated with either Vanish XT or Pro Seal. A third group received no treatment (control). Ethidium bromide with DNA was added to and mixed with the products to produce fluorescence to verify retention of the experimental products. The teeth were submersed in a lactic acid solution for 32 days to create WSLs. All sample teeth were brushed twice daily with a non-fluoride toothpaste to evaluate retention of the experimental products. Photos were taken under fluorescence microscopy and white light at three time intervals. Demineralization was quantified utilizing computer software, and photos were analyzed to obtain values for percent surface area of demineralization and surface color change. Results: Percent surface area of WSL data, both under white light conditions and fluorometric analysis, revealed a significant difference between Pro Seal and Vanish XT when compared with the control group. No significant differences were found between Pro Seal and Vanish XT treated teeth. Fluorescence evaluation revealed that both experimental products were largely removed by 32 days of brushing and acid exposure. Conclusion: Vanish XT is effective in preventing demineralization around orthodontic brackets. Its preventive efficacy is equivalent to that of Pro Seal. Palabras clave: enamel varnish, prevention, resin-modified glass ionomer, white spot lesion