For a realistic costume on Halloween, darkening your teeth creates the total look, whether you want to be a toothless ghoul or bloody-mouthed surgeon. The options for darkening teeth are safe and non-toxic, though they are for make-up purposes and not digesting.
Paint on non-toxic tooth colour. Costume stores frequently sell this type of paint-on colour for teeth, which you remove with alcohol or scrape off later, once finished.
Apply a layer of tooth wax to enhance a dark look. Use a toothpick to shape the wax to your teeth. With a little wax, apply the black colour to one tooth for a blackout, pushing the wax up to the gum. Brown tooth wax also creates a rotted look. Once finished, you scrape off the wax with your nail or a clean toothpick.
Find fake plastic teeth to slip on over your teeth. Teeth moulds are not just for vampire looks anymore. Other teeth moulds now include metallic grill, braces, rotting gums and gap teeth.
Place a blood capsule inside of your mouth, then bite down. The powder inside of the capsule mixes with food colouring to create a bloody or black look for your mouth.