Development of orthodontic brackets with antimicrobial polymeric material

Abstract

Fixed orthodontic appliances play a key role in increasing the incidence of enamel demineralization and the formation of white spots, and may act as possible sources of infection. Nanostructured silver vanadate decorated with AgNPs (AgVO3) has shown good results in the control of microorganisms in the oral cavity. The objective of this study is to evaluate the antimicrobial activity, the ability to stain the external dental structure and the bond strength of brackets made with a new antimicrobial polymeric material to dental structure. The minimum inhibitory concentration (MIC) of AgVO3 will be studied in relation to Streptococcus mutans and Streptococcus sobrinus species. Specimens will be prepared according to the percentage of AgVO3 (0% control, 2.5%, 5% and 10%) in autopolymerizable resin (Pattern Resin LS®, GC) and the inhibition halo zone will be measured. Brackets will be prepared by the incorporation of AgVO3 in the same concentrations. Fifty incisors and 50 premolars, superior and inferior, will be selected through a tooth bank, which will be divided into 5 groups according to the type of treatment received (n = 12): conventional metal brackets and bracket polymer groups (0% control, 2.5%, 5% and 10%). The dental staining will be measured through a spectrophotometer before and after the detachment of the brackets on the vestibular surface of the incisors, which will remain fixed for 6 months and stored in distilled water at 37ºC. For the shear strength test, the 50 premolars will be used. After bonding the brackets, the teeth will have their roots included in a cylindrical PVC shape with dimensions of 2.5 cm in diameter x 2 cm in height, which will be filled with self-curing acrylic resin. The specimens will be submitted to an occlusion-gingival force at a speed of 0.5 mm / min in a universal testing machine. Statistical analysis will be performed by means of parametric or non-parametric tests, depending on the distribution of the data. (AU)