As the most essential element of a perennial favourite Halloween costume, vampire fangs are widely available in costume, holiday and even grocery stores during the fall. Unfortunately, most vampire fangs are lacking in their ability to stick to the wearer's teeth and look authentic. Improve your vampire costume using an inexpensive custom-fitting technique that works on even the cheapest of dime store fangs.
Melt the craft plastic by pouring the white plastic beads into a mug full of water. Place the mug in the microwave and heat on "high" for one minute at a time, checking the beads after every minute. You'll know they're fully melted when they've changed completely from opaque to clear.
Pull the melted plastic from the cup using a fork; the melted pieces will stick together, though you may need to use the fork to gather them a little. Let the hot plastic cool for about 10 seconds, then carefully take hold of it with your hands (it will still be hot) and start to work with it, kneading it like clay.
Fill the hollow area of the gum/top portion in the vampire teeth with soft plastic, pressing it down into the cavities, then smoothing over the top. Work quickly so that the plastic will still be soft and clear when you finish; if it starts to cool and harden before you're done, use the fork to dunk it back into the hot water and soften it again.
Mould the plastic to fit your teeth. Lick your upper teeth and lips to coat them thoroughly with saliva (this will keep the plastic from sticking) and press the fangs to your teeth, pushing them so that your teeth sink into the soft plastic, making an impression. Leave the plastic in place until it hardens (this takes a couple minutes) then remove (it will come away easily).
Rinse the fangs and let them air dry.
Attach the fangs with denture adhesive. Use a small dot of adhesive on the tips of your own incisors (dry them off, first), then press the fangs into place.