Tooth decay, cavities, and stains can cause teeth to appear black. Good dental hygiene, professional cleaning, and surgery can treat this.

Cleaning your teeth and gums is even more important when you have braces; plaque can build up around your brackets and under the wire. Make sure you brush twice a day with fluoride toothpaste and ...

Brown spots can form anywhere on the teeth, ... These spots can vary in color from yellowish-brown to black-brown. ... The particles build up with repeated use and can stain the teeth.

However, whether it's safe to use directly on your teeth is up for debate. ... Baking soda may help remove plaque, which is a coating of bacteria build-up on the teeth.