Pulled from here.

Okay Step One :gather supplies

1: Party City fang filler beads: 2.99 I could not find these anywhere on the Party City website. Instead, I bought these which has decently fast shipping. There are other options, and you can buy individual tiny packs of the thermal beads. I did not because it was going to take over a month to get them.
2. Pencil
3. Buffer(optional)
4.Nail Clippers
5. Drugstore Kiss 100 artificial nails (You can also get these at Wal-mart. Get the plain, uncolored ones)
6. Thick Nail File from home: free

Step Two: fit nails to teeth

Figure out what you want your teeth to line up like. For buck, using your front two or four teeth. For troll, it depends. The guide in the link is showing Karkat teeth. Line these up in order to keep track of them.

Step Three: draw shape

Take the pencil and fake nail, and while holding the nail to your tooth, draw the shape of tooth you want. Make sure the top of the nail is close to your gum line so they won't be seen when you talk!

Step Four: use the clippers, file, and buffer to get the shape

Using the nailclippers and buffer, cut and sand the nails down to the correct shape.

Step Five: pour in the beads into a cup of hot tap water and microwave for about 45 seconds

Taking about half a packet of thermal beads (about .25-.5 oz? roughly 39 beads if you want to count them out), put them in a cup of hot water and microwave it for about a minute on high. Make sure the beads have gone clear before you proceed.

Step Six: pick beads out of cup WITH A METAL SPOON and place on the back of nails and mold!

Once the beads have cooled down a smidgen, carefully take them, put them on the back of the fake tooth, and press it to your own tooth. Mold the now-gel-like-beads to your tooth and hold it in place til the beads harden. Then, remove the nail.

"NOW HAVE FUN WITH YOUR FANGS/BUCK TEETH/ WHO KNOWS WHAT ELSE!

i still have so many nails left over to last awhile and a nice amount of beads to make maybe one or two more pairs

so i hope this helps for us homestucks on a budget or anyone who wants to make some fangs!"