well, I wouldn't recommend what I did (even though it solved the problem permanently), but you can always put some wadding where the offending tooth is, and bite like your life depends on it.

granted, you'll cut through the gum and bleed like a horse with its throat slit, but it'll actually hurt less.

again, not recommended (infection is always a possibility), and I'm only putting it out there if it takes too long or something.