Mel, do you always brush teeth together? I guess a main thing to think about is not to make it a big deal or he'll only get more defiant. We'll have to brainstorm some ways of making it fun... there's lots of little things you can do, I have to head out soon but off the top of my head:

* Make it a race / set an egg timer and see who can brush teeth the best in two minutes
* Make it a game / funny faces in the mirror
* Brush a toy's teeth first
* Buy a new, fun toothbrush
* Try and electric toothbrush, Ris LOVES hers

Can't think right now!!