check out the dental forum for more tips. our dd (26 mo) doesn't mind it too much now, but hated it for a long time.
right now dd likes to pretend there are things in her mouth we're brushing out. we'll start out by saying, "i think i see a seal in there," and she grab my arm and say, "i think i see a mama seal in there and a little baby seal". it makes the brushing take a little longer, but she's happy. also, if i have a clean baby washcloth i'll use that to clean the outside of her teeth. she especially doesn't seem to like the brush there. i usually use the brush on the chewing surfaces and the insides (next to the tongue) to avoid bites, although she rarely does that anymore.
check out the dental forum, though, if you have a chance -- here's a great, though long, thread... http://mothering.com/discussions/sho...&threadid=3697