In this tutorial we are going to show you how you can add a realistic fang to someone's mouth easily.
Here are our before and after photos
Step 1: Use your polygonal lasso to cut the tooth and paste it on a new layer. You can do this using ctrl+c to copy and ctrl+v to paste it.
Step 2: Now drag your new layer to lenghten the tooth.
Step 3: Use the Edit > Transfrom > Perspective to shape the cut-out piece so it is now looking like a real fang. Also you might want to use the eraser to help you shape the fang.
Step 4: Merge both layer (ctrl+e), and use the Clone Stamp tool to cover the joints and uneven areas and give the tooth more form.
Step 5: You can use the soft paintbrush (capacity around 20) to make sure it really blends in with other teeth.
Here's mine again, I'm sure you can do better than this..