This is another very easy achievement that you will get within the first 10 minutes of playing this game if you are achievement hunting. Just go to Stunt Mode and choose the first level which asks you to jump a certain amount of feet if I can remember correctly. The second ramp is where the jump actually takes place so just barely hold
. This will make your truck go up the ramp, get stuck a little, and topple over the ramp. This will then unlock the No Teeth! achievement.