What can be done to straighten an orthodontic wire?

Depends on the type.: All depends on the type of wire. Stainless steel wires are easier to straighten. Nickel titanium wires have memory are not as easy to straighten. Certain pliers are designed to do just that. Again, the question is very vague and would require to be more specific.

Go to a orthodontist: Not sure why you would be doing it yourself, but likely anything you attempt to perform your own treatment will backfire. If a wire needs to be adjusted, see your orthodontist.

Not much: Once the wire is kinked, the lattice structure of the metal has been permanently altered and the wire needs to be replaced before the bend moves teeth out of position. So the best way to straighten a bent wire is with a telephone...call your Orthodontic Specialist for repairs...now.