N.G.
My 2yo is the same - I have alot of sympathy. And I admit sometimes he has just cried and screamed though it. But I am trying to brush gently and avoid this as it's not much fun for either of us!
I use baby toothpaste but he just sucks it off and eats it! (I tasted it - it tastes like lollies so no wonder!
He has chosen his own toothbrush with ducks on it. I try different things all the time. Sometimes they work, then he gets sick of it and I have to try something else or we are back at square one. I think that you just have to keep persevering and trying different things without making them anxious about it (i know easier said than done!) because if you don't then it will lead to more pain later.
These are some strategies (that I can remember) that I have tried: letting him have a 'turn' then me doing it. Watching a dvd showing kids singing and brushing their teeth from the dental association (I got it free with coupons out of the newspaper so I think it was a limited thing but i'm sure there'd be other similar ones around - or books). Letting him 'brush' my teeth with my toothbrush after I brush his. Bribes with stickers and praise. Doing it when he is distracted with other things (while watching tv, etc). Letting him play with an extra toothbrush while I brush his teeth. Laying him down (it's easier to get to his teeth this way). Getting him to make funny noises (roar etc) while we brush. Brushing a toy's teeth and praising the toy. I read that getting a timer with a bell can help so long as you stop as soon as it 'dings'? Today I sung (to the tune of row row row your boat) 'brush brush brush your teeth get them really clean open wide show me your pearly whites oh they're really clean' (I got this on the internet today and I'm still searching for more strategies!) Good Luck!