Why do i have discolored teeth with braces?

Oral hygiene: Braces do not discolor teeth. Discoloration next to the braces can be caused by foods that cause stains, such as coffee, tea, colas, mustard, saffron, tomato sauce, etc. That discoloration is a surface stain that can be cleaned off. If, however, you let bacteria collect next to the braces they can produce acids that will permanently scar the enamel of the teeth and may require fillings or caps.

You don't: When did you get them placed? Are you brushing and cleaning thoroughly? Are you eating a lot of foods (coffee, tea, wine, tomato sauce, etc) that can stain your teeth normally? The braces should not have anything to do with the appearance of the teeth.

Many reasons: There are so many possible reasons including stains from coffee, tea, smoking; medications like Peridex (chlorhexidine gluconate) rinse; or simply that the dark braces give a reflective cast of darkness to the tooth that is not a permanent change at all. More serious discoloration may be from poor hygiene as described by other doctors here.