Effect of an Orthodontic Nanocement on Enamel Demineraliation Inhibition

The difficulty in removing dental plaque around orthodontic brackets may cause white spot lesions in enamel increasing caries risk. Therefore, the use of fluoride-releasing orthodontic cements is a strategy for reducing mineral loss in orthodontic patients. Besides, cement-containing nanoparticles may sustain release of high levels of fluoride. Objectives: This study aimed to evaluate the anticaries effects of using a fluoride-releasing nanocement and to compare these effects with those presented by other cements. Methods: For this, 120 bovine enamel slabs were randomly allocated in 4 groups of cements: non-fluoridated composite resin (R) fluoride-releasing composite resin (FR), resin modified glass ionomer (RMGI) and nanoparticles fluoride-releasing resin (NFR). Orthodontic brackets were bonded and specimens were suspended in BHI culture broth with 5% sucrose and inoculated with S. mutans UA 159 (5 days) for caries induction. The biofilm formed on enamel was collected and analyzed for fluoride concentration (F). Demineralization on enamel around the brackets was accessed by crossectional microhardness and energy-dispersive X-ray spectroscopy (EDX). Data were analyzed using one-way ANOVA and Tukey Kramer tests (a = 5%). Results: Only specimens from group RMGI presented values of microhardness and F-concentration in biofilme higher than those of non-fluoridated resin group (R) (p<0.01). EDX data did not statistically differ (p> 0.05) for Ca, Pi or F among the groups assessed even after caries model. Conclusions: The addition of fluoride nanoparticles did not provide anticaries effect to the tested orthodontic cement when compared to other materials. Only RMGIC was able of inhibit in vitro demineralization on enamel around orthodontic brackets.