Methods
orthodontic
Thirty individuals aged between 18 and 40 years were equally and randomly allocated into three groups: FOA (fixed orthodontic appliance), BLE (dental bleaching), and FOA + BLE (fixed orthodontic appliance + dental bleaching). The orthodontic appliances and the bleaching procedures were performed in the maxillary premolars and molars. For dental bleaching a 35% hydrogen peroxide was used. The gingival crevicular fluid (GCF) and nitric oxide (NO