Step 1
Open your picture, I used this one:
Choose any selection tool like the Polygonal Lasso Tool
, and make a selection of the fang.
Right click on the photo and choose Layer via copy, you'll get a new layer with only the fang in it.
Step 2
Go to Edit > Transform > Warp.
Strech the fang down to create a vampire tooth.
Return to the background layer, and do the same for the other tooth.
