I have a winter white.  She chews on the bars of her cage, too.  I just reach my hand into the cage and put it against her back.  She'll trust me enough to fall into my hand.  If she seems scared, offer him or her a treat to lure it onto your hand.  This also builds up it's trust in you.  To calm it down, try to play some soft music, Lite Mix 99.9 works for my hamster, maybe yours, too.  You should take him or her to the vet to check it's teeth.  Good luck!

 Try putting your hamster in an aquarium type cage or a cage where your hamster cant get it's mouth through (like the crisis cross wires) You shouldn't let the hamster free. Maybe try getting it a bigger cage so it has more space to run around. You could just take it out to play more. I let my hamsters wander around the yard for a while.