RESUMEN
INTRODUCTION: The aim of this study was to determine the effect of an orthodontic bonding adhesive containing benzalkonium chloride (BAC) on enamel demineralization. METHODS: Eighteen female Sprague-Dawley rats, aged 8 to 10 weeks, were inoculated with Streptococcus sobrinus for 5 days. The animals were randomly divided into the control, non-BAC, and BAC groups. The 6 animals in each group did not receive any brackets, received brackets on the maxillary left first molars bonded with conventional adhesive, or received brackets on the maxillary left and right first molars bonded with adhesive incorporated with 0.25% and 0.75% BAC (wt/wt), respectively. After 7 weeks, the maxillae were soaked in murexide stain to observe the surface area (mm2) and percentages of enamel demineralization on the palatal, mesial, buccal, and occlusal surfaces of the maxillary molars using color-based image analysis. RESULTS: The non-BAC and BAC groups exhibited greater enamel demineralization compared with the control group. The surface areas and percentages of enamel demineralization in the BAC group were less compared with the non-BAC group. Less enamel demineralization was noted in the animals treated with 0.75% BAC compared with those given 0.25% BAC in all areas; however, these differences were not great enough to attain statistical significance at the 0.05 level. CONCLUSIONS: The addition of BAC to an orthodontic composite has the potential to reduce the amount and percentage of enamel demineralization. In addition to being an antibacterial agent, BAC may also have an anticariogenic effect. Increased sample sizes and testing of more concentrations of BAC are recommended.